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- Add support for running the kernel in a SEV-SNP guest, over a Secure

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VM Service Module (SVSM).
 
    When running over a SVSM, different services can run at different
    protection levels, apart from the guest OS but still within the
    secure SNP environment.  They can provide services to the guest, like
    a vTPM, for example.
 
    This series adds the required facilities to interface with such a SVSM
    module.
 
  - The usual fixlets, refactoring and cleanups
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Merge tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - Add support for running the kernel in a SEV-SNP guest, over a Secure
   VM Service Module (SVSM).

   When running over a SVSM, different services can run at different
   protection levels, apart from the guest OS but still within the
   secure SNP environment. They can provide services to the guest, like
   a vTPM, for example.

   This series adds the required facilities to interface with such a
   SVSM module.

 - The usual fixlets, refactoring and cleanups

[ And as always: "SEV" is AMD's "Secure Encrypted Virtualization".

  I can't be the only one who gets all the newer x86 TLA's confused,
  can I?
              - Linus ]

* tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly
  x86/sev: Do RMP memory coverage check after max_pfn has been set
  x86/sev: Move SEV compilation units
  virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch
  x86/sev: Allow non-VMPL0 execution when an SVSM is present
  x86/sev: Extend the config-fs attestation support for an SVSM
  x86/sev: Take advantage of configfs visibility support in TSM
  fs/configfs: Add a callback to determine attribute visibility
  sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated
  virt: sev-guest: Choose the VMPCK key based on executing VMPL
  x86/sev: Provide guest VMPL level to userspace
  x86/sev: Provide SVSM discovery support
  x86/sev: Use the SVSM to create a vCPU when not in VMPL0
  x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0
  x86/sev: Use kernel provided SVSM Calling Areas
  x86/sev: Check for the presence of an SVSM in the SNP secrets page
  x86/irqflags: Provide native versions of the local_irq_save()/restore()
This commit is contained in:
Linus Torvalds 2024-07-16 11:12:25 -07:00
commit 408323581b
24 changed files with 1660 additions and 191 deletions
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63
Documentation/ABI/testing/configfs-tsm
View file

@ -31,6 +31,18 @@ Description:
Standardization v2.03 Section 4.1.8.1 MSG_REPORT_REQ.
https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56421.pdf
What: /sys/kernel/config/tsm/report/$name/manifestblob
Date: January, 2024
KernelVersion: v6.10
Contact: linux-coco@lists.linux.dev
Description:
(RO) Optional supplemental data that a TSM may emit, visibility
of this attribute depends on TSM, and may be empty if no
manifest data is available.
See 'service_provider' for information on the format of the
manifest blob.
What: /sys/kernel/config/tsm/report/$name/provider
Date: September, 2023
KernelVersion: v6.7
@ -80,3 +92,54 @@ Contact: linux-coco@lists.linux.dev
Description:
(RO) Indicates the minimum permissible value that can be written
to @privlevel.
What: /sys/kernel/config/tsm/report/$name/service_provider
Date: January, 2024
KernelVersion: v6.10
Contact: linux-coco@lists.linux.dev
Description:
(WO) Attribute is visible if a TSM implementation provider
supports the concept of attestation reports from a service
provider for TVMs, like SEV-SNP running under an SVSM.
Specifying the service provider via this attribute will create
an attestation report as specified by the service provider.
The only currently supported service provider is "svsm".
For the "svsm" service provider, see the Secure VM Service Module
for SEV-SNP Guests v1.00 Section 7. For the doc, search for
"site:amd.com "Secure VM Service Module for SEV-SNP
Guests", docID: 58019"
What: /sys/kernel/config/tsm/report/$name/service_guid
Date: January, 2024
KernelVersion: v6.10
Contact: linux-coco@lists.linux.dev
Description:
(WO) Attribute is visible if a TSM implementation provider
supports the concept of attestation reports from a service
provider for TVMs, like SEV-SNP running under an SVSM.
Specifying an empty/null GUID (00000000-0000-0000-0000-000000)
requests all active services within the service provider be
part of the attestation report. Specifying a GUID request
an attestation report of just the specified service using the
manifest form specified by the service_manifest_version
attribute.
See 'service_provider' for information on the format of the
service guid.
What: /sys/kernel/config/tsm/report/$name/service_manifest_version
Date: January, 2024
KernelVersion: v6.10
Contact: linux-coco@lists.linux.dev
Description:
(WO) Attribute is visible if a TSM implementation provider
supports the concept of attestation reports from a service
provider for TVMs, like SEV-SNP running under an SVSM.
Indicates the service manifest version requested for the
attestation report (default 0). If this field is not set by
the user, the default manifest version of the service (the
service's initial/first manifest version) is returned.
See 'service_provider' for information on the format of the
service manifest version.

12
Documentation/ABI/testing/sysfs-devices-system-cpu
View file

@ -605,6 +605,18 @@ Description: Umwait control
Note that a value of zero means there is no limit.
Low order two bits must be zero.
What: /sys/devices/system/cpu/sev
/sys/devices/system/cpu/sev/vmpl
Date: May 2024
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Secure Encrypted Virtualization (SEV) information
This directory is only present when running as an SEV-SNP guest.
vmpl: Reports the Virtual Machine Privilege Level (VMPL) at which
the SEV-SNP guest is running.
What: /sys/devices/system/cpu/svm
Date: August 2019
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>

29
Documentation/arch/x86/amd-memory-encryption.rst
View file

@ -130,4 +130,31 @@ SNP feature support.
More details in AMD64 APM[1] Vol 2: 15.34.10 SEV_STATUS MSR
[1] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/24593.pdf
Secure VM Service Module (SVSM)
===============================
SNP provides a feature called Virtual Machine Privilege Levels (VMPL) which
defines four privilege levels at which guest software can run. The most
privileged level is 0 and numerically higher numbers have lesser privileges.
More details in the AMD64 APM Vol 2, section "15.35.7 Virtual Machine
Privilege Levels", docID: 24593.
When using that feature, different services can run at different protection
levels, apart from the guest OS but still within the secure SNP environment.
They can provide services to the guest, like a vTPM, for example.
When a guest is not running at VMPL0, it needs to communicate with the software
running at VMPL0 to perform privileged operations or to interact with secure
services. An example fur such a privileged operation is PVALIDATE which is
*required* to be executed at VMPL0.
In this scenario, the software running at VMPL0 is usually called a Secure VM
Service Module (SVSM). Discovery of an SVSM and the API used to communicate
with it is documented in "Secure VM Service Module for SEV-SNP Guests", docID:
58019.
(Latest versions of the above-mentioned documents can be found by using
a search engine like duckduckgo.com and typing in:
site:amd.com "Secure VM Service Module for SEV-SNP Guests", docID: 58019
for example.)

11
Documentation/virt/coco/sev-guest.rst
View file

@ -204,6 +204,17 @@ has taken care to make use of the SEV-SNP CPUID throughout all stages of boot.
Otherwise, guest owner attestation provides no assurance that the kernel wasn't
fed incorrect values at some point during boot.
4. SEV Guest Driver Communication Key
=====================================
Communication between an SEV guest and the SEV firmware in the AMD Secure
Processor (ASP, aka PSP) is protected by a VM Platform Communication Key
(VMPCK). By default, the sev-guest driver uses the VMPCK associated with the
VM Privilege Level (VMPL) at which the guest is running. Should this key be
wiped by the sev-guest driver (see the driver for reasons why a VMPCK can be
wiped), a different key can be used by reloading the sev-guest driver and
specifying the desired key using the vmpck_id module parameter.
Reference
---------

86
arch/x86/boot/compressed/sev.c
View file

@ -127,7 +127,35 @@ static bool fault_in_kernel_space(unsigned long address)
#include "../../lib/insn.c"
/* Include code for early handlers */
#include "../../kernel/sev-shared.c"
#include "../../coco/sev/shared.c"
static struct svsm_ca *svsm_get_caa(void)
{
return boot_svsm_caa;
}
static u64 svsm_get_caa_pa(void)
{
return boot_svsm_caa_pa;
}
static int svsm_perform_call_protocol(struct svsm_call *call)
{
struct ghcb *ghcb;
int ret;
if (boot_ghcb)
ghcb = boot_ghcb;
else
ghcb = NULL;
do {
ret = ghcb ? svsm_perform_ghcb_protocol(ghcb, call)
: svsm_perform_msr_protocol(call);
} while (ret == -EAGAIN);
return ret;
}
bool sev_snp_enabled(void)
{
@ -145,8 +173,8 @@ static void __page_state_change(unsigned long paddr, enum psc_op op)
* If private -> shared then invalidate the page before requesting the
* state change in the RMP table.
*/
if (op == SNP_PAGE_STATE_SHARED && pvalidate(paddr, RMP_PG_SIZE_4K, 0))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
if (op == SNP_PAGE_STATE_SHARED)
pvalidate_4k_page(paddr, paddr, false);
/* Issue VMGEXIT to change the page state in RMP table. */
sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
@ -161,8 +189,8 @@ static void __page_state_change(unsigned long paddr, enum psc_op op)
* Now that page state is changed in the RMP table, validate it so that it is
* consistent with the RMP entry.
*/
if (op == SNP_PAGE_STATE_PRIVATE && pvalidate(paddr, RMP_PG_SIZE_4K, 1))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
if (op == SNP_PAGE_STATE_PRIVATE)
pvalidate_4k_page(paddr, paddr, true);
}
void snp_set_page_private(unsigned long paddr)
@ -255,6 +283,16 @@ void sev_es_shutdown_ghcb(void)
if (!sev_es_check_cpu_features())
error("SEV-ES CPU Features missing.");
/*
* This denotes whether to use the GHCB MSR protocol or the GHCB
* shared page to perform a GHCB request. Since the GHCB page is
* being changed to encrypted, it can't be used to perform GHCB
* requests. Clear the boot_ghcb variable so that the GHCB MSR
* protocol is used to change the GHCB page over to an encrypted
* page.
*/
boot_ghcb = NULL;
/*
* GHCB Page must be flushed from the cache and mapped encrypted again.
* Otherwise the running kernel will see strange cache effects when
@ -462,6 +500,13 @@ static bool early_snp_init(struct boot_params *bp)
*/
setup_cpuid_table(cc_info);
/*
* Record the SVSM Calling Area (CA) address if the guest is not
* running at VMPL0. The CA will be used to communicate with the
* SVSM and request its services.
*/
svsm_setup_ca(cc_info);
/*
* Pass run-time kernel a pointer to CC info via boot_params so EFI
* config table doesn't need to be searched again during early startup
@ -565,22 +610,31 @@ void sev_enable(struct boot_params *bp)
* features.
*/
if (sev_status & MSR_AMD64_SEV_SNP_ENABLED) {
if (!(get_hv_features() & GHCB_HV_FT_SNP))
u64 hv_features;
int ret;
hv_features = get_hv_features();
if (!(hv_features & GHCB_HV_FT_SNP))
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
/*
* Enforce running at VMPL0.
* Enforce running at VMPL0 or with an SVSM.
*
* RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
* higher) privilege level. Here, clear the VMPL1 permission mask of the
* GHCB page. If the guest is not running at VMPL0, this will fail.
*
* If the guest is running at VMPL0, it will succeed. Even if that operation
* modifies permission bits, it is still ok to do so currently because Linux
* SNP guests running at VMPL0 only run at VMPL0, so VMPL1 or higher
* permission mask changes are a don't-care.
* Use RMPADJUST (see the rmpadjust() function for a description of
* what the instruction does) to update the VMPL1 permissions of a
* page. If the guest is running at VMPL0, this will succeed. If the
* guest is running at any other VMPL, this will fail. Linux SNP guests
* only ever run at a single VMPL level so permission mask changes of a
* lesser-privileged VMPL are a don't-care.
*/
if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1))
ret = rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1);
/*
* Running at VMPL0 is not required if an SVSM is present and the hypervisor
* supports the required SVSM GHCB events.
*/
if (ret &&
!(snp_vmpl && (hv_features & GHCB_HV_FT_SNP_MULTI_VMPL)))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
}

1
arch/x86/coco/Makefile
View file

@ -6,3 +6,4 @@ CFLAGS_core.o += -fno-stack-protector
obj-y += core.o
obj-$(CONFIG_INTEL_TDX_GUEST) += tdx/
obj-$(CONFIG_AMD_MEM_ENCRYPT) += sev/

15
arch/x86/coco/sev/Makefile Normal file
View file

@ -0,0 +1,15 @@
# SPDX-License-Identifier: GPL-2.0
obj-y += core.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_core.o = -pg
endif
KASAN_SANITIZE_core.o := n
KMSAN_SANITIZE_core.o := n
KCOV_INSTRUMENT_core.o := n
# With some compiler versions the generated code results in boot hangs, caused
# by several compilation units. To be safe, disable all instrumentation.
KCSAN_SANITIZE := n

449
arch/x86/kernel/sev.c → arch/x86/coco/sev/core.c
View file

@ -133,16 +133,20 @@ struct ghcb_state {
struct ghcb *ghcb;
};
/* For early boot SVSM communication */
static struct svsm_ca boot_svsm_ca_page __aligned(PAGE_SIZE);
static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa);
static DEFINE_PER_CPU(struct svsm_ca *, svsm_caa);
static DEFINE_PER_CPU(u64, svsm_caa_pa);
struct sev_config {
__u64 debug : 1,
/*
* A flag used by __set_pages_state() that indicates when the
* per-CPU GHCB has been created and registered and thus can be
* used by the BSP instead of the early boot GHCB.
* Indicates when the per-CPU GHCB has been created and registered
* and thus can be used by the BSP instead of the early boot GHCB.
*
* For APs, the per-CPU GHCB is created before they are started
* and registered upon startup, so this flag can be used globally
@ -150,6 +154,15 @@ struct sev_config {
*/
ghcbs_initialized : 1,
/*
* Indicates when the per-CPU SVSM CA is to be used instead of the
* boot SVSM CA.
*
* For APs, the per-CPU SVSM CA is created as part of the AP
* bringup, so this flag can be used globally for the BSP and APs.
*/
use_cas : 1,
__reserved : 62;
};
@ -572,8 +585,61 @@ fault:
return ES_EXCEPTION;
}
static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
{
long error_code = ctxt->fi.error_code;
int trapnr = ctxt->fi.vector;
ctxt->regs->orig_ax = ctxt->fi.error_code;
switch (trapnr) {
case X86_TRAP_GP:
exc_general_protection(ctxt->regs, error_code);
break;
case X86_TRAP_UD:
exc_invalid_op(ctxt->regs);
break;
case X86_TRAP_PF:
write_cr2(ctxt->fi.cr2);
exc_page_fault(ctxt->regs, error_code);
break;
case X86_TRAP_AC:
exc_alignment_check(ctxt->regs, error_code);
break;
default:
pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n");
BUG();
}
}
/* Include code shared with pre-decompression boot stage */
#include "sev-shared.c"
#include "shared.c"
static inline struct svsm_ca *svsm_get_caa(void)
{
/*
* Use rIP-relative references when called early in the boot. If
* ->use_cas is set, then it is late in the boot and no need
* to worry about rIP-relative references.
*/
if (RIP_REL_REF(sev_cfg).use_cas)
return this_cpu_read(svsm_caa);
else
return RIP_REL_REF(boot_svsm_caa);
}
static u64 svsm_get_caa_pa(void)
{
/*
* Use rIP-relative references when called early in the boot. If
* ->use_cas is set, then it is late in the boot and no need
* to worry about rIP-relative references.
*/
if (RIP_REL_REF(sev_cfg).use_cas)
return this_cpu_read(svsm_caa_pa);
else
return RIP_REL_REF(boot_svsm_caa_pa);
}
static noinstr void __sev_put_ghcb(struct ghcb_state *state)
{
@ -600,6 +666,44 @@ static noinstr void __sev_put_ghcb(struct ghcb_state *state)
}
}
static int svsm_perform_call_protocol(struct svsm_call *call)
{
struct ghcb_state state;
unsigned long flags;
struct ghcb *ghcb;
int ret;
/*
* This can be called very early in the boot, use native functions in
* order to avoid paravirt issues.
*/
flags = native_local_irq_save();
/*
* Use rip-relative references when called early in the boot. If
* ghcbs_initialized is set, then it is late in the boot and no need
* to worry about rip-relative references in called functions.
*/
if (RIP_REL_REF(sev_cfg).ghcbs_initialized)
ghcb = __sev_get_ghcb(&state);
else if (RIP_REL_REF(boot_ghcb))
ghcb = RIP_REL_REF(boot_ghcb);
else
ghcb = NULL;
do {
ret = ghcb ? svsm_perform_ghcb_protocol(ghcb, call)
: svsm_perform_msr_protocol(call);
} while (ret == -EAGAIN);
if (RIP_REL_REF(sev_cfg).ghcbs_initialized)
__sev_put_ghcb(&state);
native_local_irq_restore(flags);
return ret;
}
void noinstr __sev_es_nmi_complete(void)
{
struct ghcb_state state;
@ -709,7 +813,6 @@ early_set_pages_state(unsigned long vaddr, unsigned long paddr,
{
unsigned long paddr_end;
u64 val;
int ret;
vaddr = vaddr & PAGE_MASK;
@ -717,12 +820,9 @@ early_set_pages_state(unsigned long vaddr, unsigned long paddr,
paddr_end = paddr + (npages << PAGE_SHIFT);
while (paddr < paddr_end) {
if (op == SNP_PAGE_STATE_SHARED) {
/* Page validation must be rescinded before changing to shared */
ret = pvalidate(vaddr, RMP_PG_SIZE_4K, false);
if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
goto e_term;
}
/* Page validation must be rescinded before changing to shared */
if (op == SNP_PAGE_STATE_SHARED)
pvalidate_4k_page(vaddr, paddr, false);
/*
* Use the MSR protocol because this function can be called before
@ -744,12 +844,9 @@ early_set_pages_state(unsigned long vaddr, unsigned long paddr,
paddr, GHCB_MSR_PSC_RESP_VAL(val)))
goto e_term;
if (op == SNP_PAGE_STATE_PRIVATE) {
/* Page validation must be performed after changing to private */
ret = pvalidate(vaddr, RMP_PG_SIZE_4K, true);
if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
goto e_term;
}
/* Page validation must be performed after changing to private */
if (op == SNP_PAGE_STATE_PRIVATE)
pvalidate_4k_page(vaddr, paddr, true);
vaddr += PAGE_SIZE;
paddr += PAGE_SIZE;
@ -913,22 +1010,49 @@ void snp_accept_memory(phys_addr_t start, phys_addr_t end)
set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE);
}
static int snp_set_vmsa(void *va, bool vmsa)
static int snp_set_vmsa(void *va, void *caa, int apic_id, bool make_vmsa)
{
u64 attrs;
int ret;
/*
* Running at VMPL0 allows the kernel to change the VMSA bit for a page
* using the RMPADJUST instruction. However, for the instruction to
* succeed it must target the permissions of a lesser privileged
* (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST
* instruction in the AMD64 APM Volume 3).
*/
attrs = 1;
if (vmsa)
attrs |= RMPADJUST_VMSA_PAGE_BIT;
if (snp_vmpl) {
struct svsm_call call = {};
unsigned long flags;
return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
local_irq_save(flags);
call.caa = this_cpu_read(svsm_caa);
call.rcx = __pa(va);
if (make_vmsa) {
/* Protocol 0, Call ID 2 */
call.rax = SVSM_CORE_CALL(SVSM_CORE_CREATE_VCPU);
call.rdx = __pa(caa);
call.r8 = apic_id;
} else {
/* Protocol 0, Call ID 3 */
call.rax = SVSM_CORE_CALL(SVSM_CORE_DELETE_VCPU);
}
ret = svsm_perform_call_protocol(&call);
local_irq_restore(flags);
} else {
/*
* If the kernel runs at VMPL0, it can change the VMSA
* bit for a page using the RMPADJUST instruction.
* However, for the instruction to succeed it must
* target the permissions of a lesser privileged (higher
* numbered) VMPL level, so use VMPL1.
*/
u64 attrs = 1;
if (make_vmsa)
attrs |= RMPADJUST_VMSA_PAGE_BIT;
ret = rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
}
return ret;
}
#define __ATTR_BASE (SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK)
@ -962,11 +1086,11 @@ static void *snp_alloc_vmsa_page(int cpu)
return page_address(p + 1);
}
static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa, int apic_id)
{
int err;
err = snp_set_vmsa(vmsa, false);
err = snp_set_vmsa(vmsa, NULL, apic_id, false);
if (err)
pr_err("clear VMSA page failed (%u), leaking page\n", err);
else
@ -977,6 +1101,7 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
{
struct sev_es_save_area *cur_vmsa, *vmsa;
struct ghcb_state state;
struct svsm_ca *caa;
unsigned long flags;
struct ghcb *ghcb;
u8 sipi_vector;
@ -1023,6 +1148,9 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
if (!vmsa)
return -ENOMEM;
/* If an SVSM is present, the SVSM per-CPU CAA will be !NULL */
caa = per_cpu(svsm_caa, cpu);
/* CR4 should maintain the MCE value */
cr4 = native_read_cr4() & X86_CR4_MCE;
@ -1070,11 +1198,11 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
* VMPL level
* SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
*/
vmsa->vmpl = 0;
vmsa->vmpl = snp_vmpl;
vmsa->sev_features = sev_status >> 2;
/* Switch the page over to a VMSA page now that it is initialized */
ret = snp_set_vmsa(vmsa, true);
ret = snp_set_vmsa(vmsa, caa, apic_id, true);
if (ret) {
pr_err("set VMSA page failed (%u)\n", ret);
free_page((unsigned long)vmsa);
@ -1090,7 +1218,10 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
vc_ghcb_invalidate(ghcb);
ghcb_set_rax(ghcb, vmsa->sev_features);
ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION);
ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE);
ghcb_set_sw_exit_info_1(ghcb,
((u64)apic_id << 32) |
((u64)snp_vmpl << 16) |
SVM_VMGEXIT_AP_CREATE);
ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa));
sev_es_wr_ghcb_msr(__pa(ghcb));
@ -1108,13 +1239,13 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
/* Perform cleanup if there was an error */
if (ret) {
snp_cleanup_vmsa(vmsa);
snp_cleanup_vmsa(vmsa, apic_id);
vmsa = NULL;
}
/* Free up any previous VMSA page */
if (cur_vmsa)
snp_cleanup_vmsa(cur_vmsa);
snp_cleanup_vmsa(cur_vmsa, apic_id);
/* Record the current VMSA page */
per_cpu(sev_vmsa, cpu) = vmsa;
@ -1209,6 +1340,17 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
/* Is it a WRMSR? */
exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
if (regs->cx == MSR_SVSM_CAA) {
/* Writes to the SVSM CAA msr are ignored */
if (exit_info_1)
return ES_OK;
regs->ax = lower_32_bits(this_cpu_read(svsm_caa_pa));
regs->dx = upper_32_bits(this_cpu_read(svsm_caa_pa));
return ES_OK;
}
ghcb_set_rcx(ghcb, regs->cx);
if (exit_info_1) {
ghcb_set_rax(ghcb, regs->ax);
@ -1346,6 +1488,18 @@ static void __init alloc_runtime_data(int cpu)
panic("Can't allocate SEV-ES runtime data");
per_cpu(runtime_data, cpu) = data;
if (snp_vmpl) {
struct svsm_ca *caa;
/* Allocate the SVSM CA page if an SVSM is present */
caa = memblock_alloc(sizeof(*caa), PAGE_SIZE);
if (!caa)
panic("Can't allocate SVSM CA page\n");
per_cpu(svsm_caa, cpu) = caa;
per_cpu(svsm_caa_pa, cpu) = __pa(caa);
}
}
static void __init init_ghcb(int cpu)
@ -1395,6 +1549,32 @@ void __init sev_es_init_vc_handling(void)
init_ghcb(cpu);
}
/* If running under an SVSM, switch to the per-cpu CA */
if (snp_vmpl) {
struct svsm_call call = {};
unsigned long flags;
int ret;
local_irq_save(flags);
/*
* SVSM_CORE_REMAP_CA call:
* RAX = 0 (Protocol=0, CallID=0)
* RCX = New CA GPA
*/
call.caa = svsm_get_caa();
call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA);
call.rcx = this_cpu_read(svsm_caa_pa);
ret = svsm_perform_call_protocol(&call);
if (ret)
panic("Can't remap the SVSM CA, ret=%d, rax_out=0x%llx\n",
ret, call.rax_out);
sev_cfg.use_cas = true;
local_irq_restore(flags);
}
sev_es_setup_play_dead();
/* Secondary CPUs use the runtime #VC handler */
@ -1819,33 +1999,6 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
return result;
}
static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
{
long error_code = ctxt->fi.error_code;
int trapnr = ctxt->fi.vector;
ctxt->regs->orig_ax = ctxt->fi.error_code;
switch (trapnr) {
case X86_TRAP_GP:
exc_general_protection(ctxt->regs, error_code);
break;
case X86_TRAP_UD:
exc_invalid_op(ctxt->regs);
break;
case X86_TRAP_PF:
write_cr2(ctxt->fi.cr2);
exc_page_fault(ctxt->regs, error_code);
break;
case X86_TRAP_AC:
exc_alignment_check(ctxt->regs, error_code);
break;
default:
pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n");
BUG();
}
}
static __always_inline bool is_vc2_stack(unsigned long sp)
{
return (sp >= __this_cpu_ist_bottom_va(VC2) && sp < __this_cpu_ist_top_va(VC2));
@ -2095,6 +2248,47 @@ found_cc_info:
return cc_info;
}
static __head void svsm_setup(struct cc_blob_sev_info *cc_info)
{
struct svsm_call call = {};
int ret;
u64 pa;
/*
* Record the SVSM Calling Area address (CAA) if the guest is not
* running at VMPL0. The CA will be used to communicate with the
* SVSM to perform the SVSM services.
*/
if (!svsm_setup_ca(cc_info))
return;
/*
* It is very early in the boot and the kernel is running identity
* mapped but without having adjusted the pagetables to where the
* kernel was loaded (physbase), so the get the CA address using
* RIP-relative addressing.
*/
pa = (u64)&RIP_REL_REF(boot_svsm_ca_page);
/*
* Switch over to the boot SVSM CA while the current CA is still
* addressable. There is no GHCB at this point so use the MSR protocol.
*
* SVSM_CORE_REMAP_CA call:
* RAX = 0 (Protocol=0, CallID=0)
* RCX = New CA GPA
*/
call.caa = svsm_get_caa();
call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA);
call.rcx = pa;
ret = svsm_perform_call_protocol(&call);
if (ret)
panic("Can't remap the SVSM CA, ret=%d, rax_out=0x%llx\n", ret, call.rax_out);
RIP_REL_REF(boot_svsm_caa) = (struct svsm_ca *)pa;
RIP_REL_REF(boot_svsm_caa_pa) = pa;
}
bool __head snp_init(struct boot_params *bp)
{
struct cc_blob_sev_info *cc_info;
@ -2108,6 +2302,8 @@ bool __head snp_init(struct boot_params *bp)
setup_cpuid_table(cc_info);
svsm_setup(cc_info);
/*
* The CC blob will be used later to access the secrets page. Cache
* it here like the boot kernel does.
@ -2156,23 +2352,27 @@ static void dump_cpuid_table(void)
* expected, but that initialization happens too early in boot to print any
* sort of indicator, and there's not really any other good place to do it,
* so do it here.
*
* If running as an SNP guest, report the current VM privilege level (VMPL).
*/
static int __init report_cpuid_table(void)
static int __init report_snp_info(void)
{
const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
if (!cpuid_table->count)
return 0;
if (cpuid_table->count) {
pr_info("Using SNP CPUID table, %d entries present.\n",
cpuid_table->count);
pr_info("Using SNP CPUID table, %d entries present.\n",
cpuid_table->count);
if (sev_cfg.debug)
dump_cpuid_table();
}
if (sev_cfg.debug)
dump_cpuid_table();
if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
pr_info("SNP running at VMPL%u.\n", snp_vmpl);
return 0;
}
arch_initcall(report_cpuid_table);
arch_initcall(report_snp_info);
static int __init init_sev_config(char *str)
{
@ -2191,6 +2391,56 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
static void update_attest_input(struct svsm_call *call, struct svsm_attest_call *input)
{
/* If (new) lengths have been returned, propagate them up */
if (call->rcx_out != call->rcx)
input->manifest_buf.len = call->rcx_out;
if (call->rdx_out != call->rdx)
input->certificates_buf.len = call->rdx_out;
if (call->r8_out != call->r8)
input->report_buf.len = call->r8_out;
}
int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call,
struct svsm_attest_call *input)
{
struct svsm_attest_call *ac;
unsigned long flags;
u64 attest_call_pa;
int ret;
if (!snp_vmpl)
return -EINVAL;
local_irq_save(flags);
call->caa = svsm_get_caa();
ac = (struct svsm_attest_call *)call->caa->svsm_buffer;
attest_call_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer);
*ac = *input;
/*
* Set input registers for the request and set RDX and R8 to known
* values in order to detect length values being returned in them.
*/
call->rax = call_id;
call->rcx = attest_call_pa;
call->rdx = -1;
call->r8 = -1;
ret = svsm_perform_call_protocol(call);
update_attest_input(call, input);
local_irq_restore(flags);
return ret;
}
EXPORT_SYMBOL_GPL(snp_issue_svsm_attest_req);
int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
{
struct ghcb_state state;
@ -2299,3 +2549,58 @@ void sev_show_status(void)
}
pr_cont("\n");
}
void __init snp_update_svsm_ca(void)
{
if (!snp_vmpl)
return;
/* Update the CAA to a proper kernel address */
boot_svsm_caa = &boot_svsm_ca_page;
}
#ifdef CONFIG_SYSFS
static ssize_t vmpl_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", snp_vmpl);
}
static struct kobj_attribute vmpl_attr = __ATTR_RO(vmpl);
static struct attribute *vmpl_attrs[] = {
&vmpl_attr.attr,
NULL
};
static struct attribute_group sev_attr_group = {
.attrs = vmpl_attrs,
};
static int __init sev_sysfs_init(void)
{
struct kobject *sev_kobj;
struct device *dev_root;
int ret;
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
dev_root = bus_get_dev_root(&cpu_subsys);
if (!dev_root)
return -ENODEV;
sev_kobj = kobject_create_and_add("sev", &dev_root->kobj);
put_device(dev_root);
if (!sev_kobj)
return -ENOMEM;
ret = sysfs_create_group(sev_kobj, &sev_attr_group);
if (ret)
kobject_put(sev_kobj);
return ret;
}
arch_initcall(sev_sysfs_init);
#endif // CONFIG_SYSFS

464
arch/x86/kernel/sev-shared.c → arch/x86/coco/sev/shared.c
View file

@ -21,8 +21,30 @@
#define WARN(condition, format...) (!!(condition))
#define sev_printk(fmt, ...)
#define sev_printk_rtl(fmt, ...)
#undef vc_forward_exception
#define vc_forward_exception(c) panic("SNP: Hypervisor requested exception\n")
#endif
/*
* SVSM related information:
* When running under an SVSM, the VMPL that Linux is executing at must be
* non-zero. The VMPL is therefore used to indicate the presence of an SVSM.
*
* During boot, the page tables are set up as identity mapped and later
* changed to use kernel virtual addresses. Maintain separate virtual and
* physical addresses for the CAA to allow SVSM functions to be used during
* early boot, both with identity mapped virtual addresses and proper kernel
* virtual addresses.
*/
u8 snp_vmpl __ro_after_init;
EXPORT_SYMBOL_GPL(snp_vmpl);
static struct svsm_ca *boot_svsm_caa __ro_after_init;
static u64 boot_svsm_caa_pa __ro_after_init;
static struct svsm_ca *svsm_get_caa(void);
static u64 svsm_get_caa_pa(void);
static int svsm_perform_call_protocol(struct svsm_call *call);
/* I/O parameters for CPUID-related helpers */
struct cpuid_leaf {
u32 fn;
@ -229,6 +251,126 @@ static enum es_result verify_exception_info(struct ghcb *ghcb, struct es_em_ctxt
return ES_VMM_ERROR;
}
static inline int svsm_process_result_codes(struct svsm_call *call)
{
switch (call->rax_out) {
case SVSM_SUCCESS:
return 0;
case SVSM_ERR_INCOMPLETE:
case SVSM_ERR_BUSY:
return -EAGAIN;
default:
return -EINVAL;
}
}
/*
* Issue a VMGEXIT to call the SVSM:
* - Load the SVSM register state (RAX, RCX, RDX, R8 and R9)
* - Set the CA call pending field to 1
* - Issue VMGEXIT
* - Save the SVSM return register state (RAX, RCX, RDX, R8 and R9)
* - Perform atomic exchange of the CA call pending field
*
* - See the "Secure VM Service Module for SEV-SNP Guests" specification for
* details on the calling convention.
* - The calling convention loosely follows the Microsoft X64 calling
* convention by putting arguments in RCX, RDX, R8 and R9.
* - RAX specifies the SVSM protocol/callid as input and the return code
* as output.
*/
static __always_inline void svsm_issue_call(struct svsm_call *call, u8 *pending)
{
register unsigned long rax asm("rax") = call->rax;
register unsigned long rcx asm("rcx") = call->rcx;
register unsigned long rdx asm("rdx") = call->rdx;
register unsigned long r8 asm("r8") = call->r8;
register unsigned long r9 asm("r9") = call->r9;
call->caa->call_pending = 1;
asm volatile("rep; vmmcall\n\t"
: "+r" (rax), "+r" (rcx), "+r" (rdx), "+r" (r8), "+r" (r9)
: : "memory");
*pending = xchg(&call->caa->call_pending, *pending);
call->rax_out = rax;
call->rcx_out = rcx;
call->rdx_out = rdx;
call->r8_out = r8;
call->r9_out = r9;
}
static int svsm_perform_msr_protocol(struct svsm_call *call)
{
u8 pending = 0;
u64 val, resp;
/*
* When using the MSR protocol, be sure to save and restore
* the current MSR value.
*/
val = sev_es_rd_ghcb_msr();
sev_es_wr_ghcb_msr(GHCB_MSR_VMPL_REQ_LEVEL(0));
svsm_issue_call(call, &pending);
resp = sev_es_rd_ghcb_msr();
sev_es_wr_ghcb_msr(val);
if (pending)
return -EINVAL;
if (GHCB_RESP_CODE(resp) != GHCB_MSR_VMPL_RESP)
return -EINVAL;
if (GHCB_MSR_VMPL_RESP_VAL(resp))
return -EINVAL;
return svsm_process_result_codes(call);
}
static int svsm_perform_ghcb_protocol(struct ghcb *ghcb, struct svsm_call *call)
{
struct es_em_ctxt ctxt;
u8 pending = 0;
vc_ghcb_invalidate(ghcb);
/*
* Fill in protocol and format specifiers. This can be called very early
* in the boot, so use rip-relative references as needed.
*/
ghcb->protocol_version = RIP_REL_REF(ghcb_version);
ghcb->ghcb_usage = GHCB_DEFAULT_USAGE;
ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_SNP_RUN_VMPL);
ghcb_set_sw_exit_info_1(ghcb, 0);
ghcb_set_sw_exit_info_2(ghcb, 0);
sev_es_wr_ghcb_msr(__pa(ghcb));
svsm_issue_call(call, &pending);
if (pending)
return -EINVAL;
switch (verify_exception_info(ghcb, &ctxt)) {
case ES_OK:
break;
case ES_EXCEPTION:
vc_forward_exception(&ctxt);
fallthrough;
default:
return -EINVAL;
}
return svsm_process_result_codes(call);
}
static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
struct es_em_ctxt *ctxt,
u64 exit_code, u64 exit_info_1,
@ -1079,40 +1221,270 @@ static void __head setup_cpuid_table(const struct cc_blob_sev_info *cc_info)
}
}
static void pvalidate_pages(struct snp_psc_desc *desc)
static inline void __pval_terminate(u64 pfn, bool action, unsigned int page_size,
int ret, u64 svsm_ret)
{
WARN(1, "PVALIDATE failure: pfn: 0x%llx, action: %u, size: %u, ret: %d, svsm_ret: 0x%llx\n",
pfn, action, page_size, ret, svsm_ret);
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
}
static void svsm_pval_terminate(struct svsm_pvalidate_call *pc, int ret, u64 svsm_ret)
{
unsigned int page_size;
bool action;
u64 pfn;
pfn = pc->entry[pc->cur_index].pfn;
action = pc->entry[pc->cur_index].action;
page_size = pc->entry[pc->cur_index].page_size;
__pval_terminate(pfn, action, page_size, ret, svsm_ret);
}
static void svsm_pval_4k_page(unsigned long paddr, bool validate)
{
struct svsm_pvalidate_call *pc;
struct svsm_call call = {};
unsigned long flags;
u64 pc_pa;
int ret;
/*
* This can be called very early in the boot, use native functions in
* order to avoid paravirt issues.
*/
flags = native_local_irq_save();
call.caa = svsm_get_caa();
pc = (struct svsm_pvalidate_call *)call.caa->svsm_buffer;
pc_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer);
pc->num_entries = 1;
pc->cur_index = 0;
pc->entry[0].page_size = RMP_PG_SIZE_4K;
pc->entry[0].action = validate;
pc->entry[0].ignore_cf = 0;
pc->entry[0].pfn = paddr >> PAGE_SHIFT;
/* Protocol 0, Call ID 1 */
call.rax = SVSM_CORE_CALL(SVSM_CORE_PVALIDATE);
call.rcx = pc_pa;
ret = svsm_perform_call_protocol(&call);
if (ret)
svsm_pval_terminate(pc, ret, call.rax_out);
native_local_irq_restore(flags);
}
static void pvalidate_4k_page(unsigned long vaddr, unsigned long paddr, bool validate)
{
int ret;
/*
* This can be called very early during boot, so use rIP-relative
* references as needed.
*/
if (RIP_REL_REF(snp_vmpl)) {
svsm_pval_4k_page(paddr, validate);
} else {
ret = pvalidate(vaddr, RMP_PG_SIZE_4K, validate);
if (ret)
__pval_terminate(PHYS_PFN(paddr), validate, RMP_PG_SIZE_4K, ret, 0);
}
}
static void pval_pages(struct snp_psc_desc *desc)
{
struct psc_entry *e;
unsigned long vaddr;
unsigned int size;
unsigned int i;
bool validate;
u64 pfn;
int rc;
for (i = 0; i <= desc->hdr.end_entry; i++) {
e = &desc->entries[i];
vaddr = (unsigned long)pfn_to_kaddr(e->gfn);
pfn = e->gfn;
vaddr = (unsigned long)pfn_to_kaddr(pfn);
size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
validate = e->operation == SNP_PAGE_STATE_PRIVATE;
rc = pvalidate(vaddr, size, validate);
if (!rc)
continue;
if (rc == PVALIDATE_FAIL_SIZEMISMATCH && size == RMP_PG_SIZE_2M) {
unsigned long vaddr_end = vaddr + PMD_SIZE;
for (; vaddr < vaddr_end; vaddr += PAGE_SIZE) {
for (; vaddr < vaddr_end; vaddr += PAGE_SIZE, pfn++) {
rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate);
if (rc)
break;
__pval_terminate(pfn, validate, RMP_PG_SIZE_4K, rc, 0);
}
}
if (rc) {
WARN(1, "Failed to validate address 0x%lx ret %d", vaddr, rc);
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
} else {
__pval_terminate(pfn, validate, size, rc, 0);
}
}
}
static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
struct svsm_pvalidate_call *pc)
{
struct svsm_pvalidate_entry *pe;
/* Nothing in the CA yet */
pc->num_entries = 0;
pc->cur_index = 0;
pe = &pc->entry[0];
while (pfn < pfn_end) {
pe->page_size = RMP_PG_SIZE_4K;
pe->action = action;
pe->ignore_cf = 0;
pe->pfn = pfn;
pe++;
pfn++;
pc->num_entries++;
if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT)
break;
}
return pfn;
}
static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int desc_entry,
struct svsm_pvalidate_call *pc)
{
struct svsm_pvalidate_entry *pe;
struct psc_entry *e;
/* Nothing in the CA yet */
pc->num_entries = 0;
pc->cur_index = 0;
pe = &pc->entry[0];
e = &desc->entries[desc_entry];
while (desc_entry <= desc->hdr.end_entry) {
pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
pe->action = e->operation == SNP_PAGE_STATE_PRIVATE;
pe->ignore_cf = 0;
pe->pfn = e->gfn;
pe++;
e++;
desc_entry++;
pc->num_entries++;
if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT)
break;
}
return desc_entry;
}
static void svsm_pval_pages(struct snp_psc_desc *desc)
{
struct svsm_pvalidate_entry pv_4k[VMGEXIT_PSC_MAX_ENTRY];
unsigned int i, pv_4k_count = 0;
struct svsm_pvalidate_call *pc;
struct svsm_call call = {};
unsigned long flags;
bool action;
u64 pc_pa;
int ret;
/*
* This can be called very early in the boot, use native functions in
* order to avoid paravirt issues.
*/
flags = native_local_irq_save();
/*
* The SVSM calling area (CA) can support processing 510 entries at a
* time. Loop through the Page State Change descriptor until the CA is
* full or the last entry in the descriptor is reached, at which time
* the SVSM is invoked. This repeats until all entries in the descriptor
* are processed.
*/
call.caa = svsm_get_caa();
pc = (struct svsm_pvalidate_call *)call.caa->svsm_buffer;
pc_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer);
/* Protocol 0, Call ID 1 */
call.rax = SVSM_CORE_CALL(SVSM_CORE_PVALIDATE);
call.rcx = pc_pa;
for (i = 0; i <= desc->hdr.end_entry;) {
i = svsm_build_ca_from_psc_desc(desc, i, pc);
do {
ret = svsm_perform_call_protocol(&call);
if (!ret)
continue;
/*
* Check if the entry failed because of an RMP mismatch (a
* PVALIDATE at 2M was requested, but the page is mapped in
* the RMP as 4K).
*/
if (call.rax_out == SVSM_PVALIDATE_FAIL_SIZEMISMATCH &&
pc->entry[pc->cur_index].page_size == RMP_PG_SIZE_2M) {
/* Save this entry for post-processing at 4K */
pv_4k[pv_4k_count++] = pc->entry[pc->cur_index];
/* Skip to the next one unless at the end of the list */
pc->cur_index++;
if (pc->cur_index < pc->num_entries)
ret = -EAGAIN;
else
ret = 0;
}
} while (ret == -EAGAIN);
if (ret)
svsm_pval_terminate(pc, ret, call.rax_out);
}
/* Process any entries that failed to be validated at 2M and validate them at 4K */
for (i = 0; i < pv_4k_count; i++) {
u64 pfn, pfn_end;
action = pv_4k[i].action;
pfn = pv_4k[i].pfn;
pfn_end = pfn + 512;
while (pfn < pfn_end) {
pfn = svsm_build_ca_from_pfn_range(pfn, pfn_end, action, pc);
ret = svsm_perform_call_protocol(&call);
if (ret)
svsm_pval_terminate(pc, ret, call.rax_out);
}
}
native_local_irq_restore(flags);
}
static void pvalidate_pages(struct snp_psc_desc *desc)
{
if (snp_vmpl)
svsm_pval_pages(desc);
else
pval_pages(desc);
}
static int vmgexit_psc(struct ghcb *ghcb, struct snp_psc_desc *desc)
{
int cur_entry, end_entry, ret = 0;
@ -1269,3 +1641,77 @@ static enum es_result vc_check_opcode_bytes(struct es_em_ctxt *ctxt,
return ES_UNSUPPORTED;
}
/*
* Maintain the GPA of the SVSM Calling Area (CA) in order to utilize the SVSM
* services needed when not running in VMPL0.
*/
static bool __head svsm_setup_ca(const struct cc_blob_sev_info *cc_info)
{
struct snp_secrets_page *secrets_page;
struct snp_cpuid_table *cpuid_table;
unsigned int i;
u64 caa;
BUILD_BUG_ON(sizeof(*secrets_page) != PAGE_SIZE);
/*
* Check if running at VMPL0.
*
* Use RMPADJUST (see the rmpadjust() function for a description of what
* the instruction does) to update the VMPL1 permissions of a page. If
* the guest is running at VMPL0, this will succeed and implies there is
* no SVSM. If the guest is running at any other VMPL, this will fail.
* Linux SNP guests only ever run at a single VMPL level so permission mask
* changes of a lesser-privileged VMPL are a don't-care.
*
* Use a rip-relative reference to obtain the proper address, since this
* routine is running identity mapped when called, both by the decompressor
* code and the early kernel code.
*/
if (!rmpadjust((unsigned long)&RIP_REL_REF(boot_ghcb_page), RMP_PG_SIZE_4K, 1))
return false;
/*
* Not running at VMPL0, ensure everything has been properly supplied
* for running under an SVSM.
*/
if (!cc_info || !cc_info->secrets_phys || cc_info->secrets_len != PAGE_SIZE)
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECRETS_PAGE);
secrets_page = (struct snp_secrets_page *)cc_info->secrets_phys;
if (!secrets_page->svsm_size)
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NO_SVSM);
if (!secrets_page->svsm_guest_vmpl)
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_VMPL0);
RIP_REL_REF(snp_vmpl) = secrets_page->svsm_guest_vmpl;
caa = secrets_page->svsm_caa;
/*
* An open-coded PAGE_ALIGNED() in order to avoid including
* kernel-proper headers into the decompressor.
*/
if (caa & (PAGE_SIZE - 1))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CAA);
/*
* The CA is identity mapped when this routine is called, both by the
* decompressor code and the early kernel code.
*/
RIP_REL_REF(boot_svsm_caa) = (struct svsm_ca *)caa;
RIP_REL_REF(boot_svsm_caa_pa) = caa;
/* Advertise the SVSM presence via CPUID. */
cpuid_table = (struct snp_cpuid_table *)snp_cpuid_get_table();
for (i = 0; i < cpuid_table->count; i++) {
struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
if (fn->eax_in == 0x8000001f)
fn->eax |= BIT(28);
}
return true;
}

1
arch/x86/include/asm/cpufeatures.h
View file

@ -446,6 +446,7 @@
#define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* Virtual TSC_AUX */
#define X86_FEATURE_SME_COHERENT (19*32+10) /* AMD hardware-enforced cache coherency */
#define X86_FEATURE_DEBUG_SWAP (19*32+14) /* "debug_swap" AMD SEV-ES full debug state swap support */
#define X86_FEATURE_SVSM (19*32+28) /* "svsm" SVSM present */
/* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word 20 */
#define X86_FEATURE_NO_NESTED_DATA_BP (20*32+ 0) /* No Nested Data Breakpoints */

20
arch/x86/include/asm/irqflags.h
View file

@ -54,6 +54,26 @@ static __always_inline void native_halt(void)
asm volatile("hlt": : :"memory");
}
static __always_inline int native_irqs_disabled_flags(unsigned long flags)
{
return !(flags & X86_EFLAGS_IF);
}
static __always_inline unsigned long native_local_irq_save(void)
{
unsigned long flags = native_save_fl();
native_irq_disable();
return flags;
}
static __always_inline void native_local_irq_restore(unsigned long flags)
{
if (!native_irqs_disabled_flags(flags))
native_irq_enable();
}
#endif
#ifdef CONFIG_PARAVIRT_XXL

2
arch/x86/include/asm/msr-index.h
View file

@ -660,6 +660,8 @@
#define MSR_AMD64_RMP_BASE 0xc0010132
#define MSR_AMD64_RMP_END 0xc0010133
#define MSR_SVSM_CAA 0xc001f000
/* AMD Collaborative Processor Performance Control MSRs */
#define MSR_AMD_CPPC_CAP1 0xc00102b0
#define MSR_AMD_CPPC_ENABLE 0xc00102b1

18
arch/x86/include/asm/sev-common.h
View file

@ -98,6 +98,19 @@ enum psc_op {
/* GHCBData[63:32] */ \
(((u64)(val) & GENMASK_ULL(63, 32)) >> 32)
/* GHCB Run at VMPL Request/Response */
#define GHCB_MSR_VMPL_REQ 0x016
#define GHCB_MSR_VMPL_REQ_LEVEL(v) \
/* GHCBData[39:32] */ \
(((u64)(v) & GENMASK_ULL(7, 0) << 32) | \
/* GHCBDdata[11:0] */ \
GHCB_MSR_VMPL_REQ)
#define GHCB_MSR_VMPL_RESP 0x017
#define GHCB_MSR_VMPL_RESP_VAL(v) \
/* GHCBData[63:32] */ \
(((u64)(v) & GENMASK_ULL(63, 32)) >> 32)
/* GHCB Hypervisor Feature Request/Response */
#define GHCB_MSR_HV_FT_REQ 0x080
#define GHCB_MSR_HV_FT_RESP 0x081
@ -109,6 +122,7 @@ enum psc_op {
#define GHCB_HV_FT_SNP BIT_ULL(0)
#define GHCB_HV_FT_SNP_AP_CREATION BIT_ULL(1)
#define GHCB_HV_FT_SNP_MULTI_VMPL BIT_ULL(5)
/*
* SNP Page State Change NAE event
@ -163,6 +177,10 @@ struct snp_psc_desc {
#define GHCB_TERM_NOT_VMPL0 3 /* SNP guest is not running at VMPL-0 */
#define GHCB_TERM_CPUID 4 /* CPUID-validation failure */
#define GHCB_TERM_CPUID_HV 5 /* CPUID failure during hypervisor fallback */
#define GHCB_TERM_SECRETS_PAGE 6 /* Secrets page failure */
#define GHCB_TERM_NO_SVSM 7 /* SVSM is not advertised in the secrets page */
#define GHCB_TERM_SVSM_VMPL0 8 /* SVSM is present but has set VMPL to 0 */
#define GHCB_TERM_SVSM_CAA 9 /* SVSM is present but CAA is not page aligned */
#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)

135
arch/x86/include/asm/sev.h
View file

@ -152,10 +152,119 @@ struct snp_secrets_page {
u8 vmpck2[VMPCK_KEY_LEN];
u8 vmpck3[VMPCK_KEY_LEN];
struct secrets_os_area os_area;
u8 rsvd3[3840];
u8 vmsa_tweak_bitmap[64];
/* SVSM fields */
u64 svsm_base;
u64 svsm_size;
u64 svsm_caa;
u32 svsm_max_version;
u8 svsm_guest_vmpl;
u8 rsvd3[3];
/* Remainder of page */
u8 rsvd4[3744];
} __packed;
/*
* The SVSM Calling Area (CA) related structures.
*/
struct svsm_ca {
u8 call_pending;
u8 mem_available;
u8 rsvd1[6];
u8 svsm_buffer[PAGE_SIZE - 8];
};
#define SVSM_SUCCESS 0
#define SVSM_ERR_INCOMPLETE 0x80000000
#define SVSM_ERR_UNSUPPORTED_PROTOCOL 0x80000001
#define SVSM_ERR_UNSUPPORTED_CALL 0x80000002
#define SVSM_ERR_INVALID_ADDRESS 0x80000003
#define SVSM_ERR_INVALID_FORMAT 0x80000004
#define SVSM_ERR_INVALID_PARAMETER 0x80000005
#define SVSM_ERR_INVALID_REQUEST 0x80000006
#define SVSM_ERR_BUSY 0x80000007
#define SVSM_PVALIDATE_FAIL_SIZEMISMATCH 0x80001006
/*
* The SVSM PVALIDATE related structures
*/
struct svsm_pvalidate_entry {
u64 page_size : 2,
action : 1,
ignore_cf : 1,
rsvd : 8,
pfn : 52;
};
struct svsm_pvalidate_call {
u16 num_entries;
u16 cur_index;
u8 rsvd1[4];
struct svsm_pvalidate_entry entry[];
};
#define SVSM_PVALIDATE_MAX_COUNT ((sizeof_field(struct svsm_ca, svsm_buffer) - \
offsetof(struct svsm_pvalidate_call, entry)) / \
sizeof(struct svsm_pvalidate_entry))
/*
* The SVSM Attestation related structures
*/
struct svsm_loc_entry {
u64 pa;
u32 len;
u8 rsvd[4];
};
struct svsm_attest_call {
struct svsm_loc_entry report_buf;
struct svsm_loc_entry nonce;
struct svsm_loc_entry manifest_buf;
struct svsm_loc_entry certificates_buf;
/* For attesting a single service */
u8 service_guid[16];
u32 service_manifest_ver;
u8 rsvd[4];
};
/*
* SVSM protocol structure
*/
struct svsm_call {
struct svsm_ca *caa;
u64 rax;
u64 rcx;
u64 rdx;
u64 r8;
u64 r9;
u64 rax_out;
u64 rcx_out;
u64 rdx_out;
u64 r8_out;
u64 r9_out;
};
#define SVSM_CORE_CALL(x) ((0ULL << 32) | (x))
#define SVSM_CORE_REMAP_CA 0
#define SVSM_CORE_PVALIDATE 1
#define SVSM_CORE_CREATE_VCPU 2
#define SVSM_CORE_DELETE_VCPU 3
#define SVSM_ATTEST_CALL(x) ((1ULL << 32) | (x))
#define SVSM_ATTEST_SERVICES 0
#define SVSM_ATTEST_SINGLE_SERVICE 1
#ifdef CONFIG_AMD_MEM_ENCRYPT
extern u8 snp_vmpl;
extern void __sev_es_ist_enter(struct pt_regs *regs);
extern void __sev_es_ist_exit(void);
static __always_inline void sev_es_ist_enter(struct pt_regs *regs)
@ -181,6 +290,14 @@ static __always_inline void sev_es_nmi_complete(void)
extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd);
extern void sev_enable(struct boot_params *bp);
/*
* RMPADJUST modifies the RMP permissions of a page of a lesser-
* privileged (numerically higher) VMPL.
*
* If the guest is running at a higher-privilege than the privilege
* level the instruction is targeting, the instruction will succeed,
* otherwise, it will fail.
*/
static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs)
{
int rc;
@ -225,11 +342,16 @@ bool snp_init(struct boot_params *bp);
void __noreturn snp_abort(void);
void snp_dmi_setup(void);
int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, struct svsm_attest_call *input);
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
void sev_show_status(void);
#else
void snp_update_svsm_ca(void);
#else /* !CONFIG_AMD_MEM_ENCRYPT */
#define snp_vmpl 0
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; }
@ -253,12 +375,17 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in
{
return -ENOTTY;
}
static inline int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, struct svsm_attest_call *input)
{
return -ENOTTY;
}
static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
static inline void sev_show_status(void) { }
#endif
static inline void snp_update_svsm_ca(void) { }
#endif /* CONFIG_AMD_MEM_ENCRYPT */
#ifdef CONFIG_KVM_AMD_SEV
bool snp_probe_rmptable_info(void);

1
arch/x86/include/uapi/asm/svm.h
View file

@ -115,6 +115,7 @@
#define SVM_VMGEXIT_AP_CREATE_ON_INIT 0
#define SVM_VMGEXIT_AP_CREATE 1
#define SVM_VMGEXIT_AP_DESTROY 2
#define SVM_VMGEXIT_SNP_RUN_VMPL 0x80000018
#define SVM_VMGEXIT_HV_FEATURES 0x8000fffd
#define SVM_VMGEXIT_TERM_REQUEST 0x8000fffe
#define SVM_VMGEXIT_TERM_REASON(reason_set, reason_code) \

6
arch/x86/kernel/Makefile
View file

@ -17,7 +17,6 @@ CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_early_printk.o = -pg
CFLAGS_REMOVE_head64.o = -pg
CFLAGS_REMOVE_head32.o = -pg
CFLAGS_REMOVE_sev.o = -pg
CFLAGS_REMOVE_rethook.o = -pg
endif
@ -26,19 +25,16 @@ KASAN_SANITIZE_dumpstack.o := n
KASAN_SANITIZE_dumpstack_$(BITS).o := n
KASAN_SANITIZE_stacktrace.o := n
KASAN_SANITIZE_paravirt.o := n
KASAN_SANITIZE_sev.o := n
# With some compiler versions the generated code results in boot hangs, caused
# by several compilation units. To be safe, disable all instrumentation.
KCSAN_SANITIZE := n
KMSAN_SANITIZE_head$(BITS).o := n
KMSAN_SANITIZE_nmi.o := n
KMSAN_SANITIZE_sev.o := n
# If instrumentation of the following files is enabled, boot hangs during
# first second.
KCOV_INSTRUMENT_head$(BITS).o := n
KCOV_INSTRUMENT_sev.o := n
CFLAGS_irq.o := -I $(src)/../include/asm/trace
@ -142,8 +138,6 @@ obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o
obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += sev.o
obj-$(CONFIG_CFI_CLANG) += cfi.o
obj-$(CONFIG_CALL_THUNKS) += callthunks.o

8
arch/x86/mm/mem_encrypt_amd.c
View file

@ -2,7 +2,7 @@
/*
* AMD Memory Encryption Support
*
* Copyright (C) 2016 Advanced Micro Devices, Inc.
* Copyright (C) 2016-2024 Advanced Micro Devices, Inc.
*
* Author: Tom Lendacky <thomas.lendacky@amd.com>
*/
@ -510,6 +510,12 @@ void __init sme_early_init(void)
*/
x86_init.resources.dmi_setup = snp_dmi_setup;
}
/*
* Switch the SVSM CA mapping (if active) from identity mapped to
* kernel mapped.
*/
snp_update_svsm_ca();
}
void __init mem_encrypt_free_decrypted_mem(void)

44
arch/x86/virt/svm/sev.c
View file

@ -120,7 +120,7 @@ static __init void snp_enable(void *arg)
bool snp_probe_rmptable_info(void)
{
u64 max_rmp_pfn, calc_rmp_sz, rmp_sz, rmp_base, rmp_end;
u64 rmp_sz, rmp_base, rmp_end;
rdmsrl(MSR_AMD64_RMP_BASE, rmp_base);
rdmsrl(MSR_AMD64_RMP_END, rmp_end);
@ -137,28 +137,11 @@ bool snp_probe_rmptable_info(void)
rmp_sz = rmp_end - rmp_base + 1;
/*
* Calculate the amount the memory that must be reserved by the BIOS to
* address the whole RAM, including the bookkeeping area. The RMP itself
* must also be covered.
*/
max_rmp_pfn = max_pfn;
if (PHYS_PFN(rmp_end) > max_pfn)
max_rmp_pfn = PHYS_PFN(rmp_end);
calc_rmp_sz = (max_rmp_pfn << 4) + RMPTABLE_CPU_BOOKKEEPING_SZ;
if (calc_rmp_sz > rmp_sz) {
pr_err("Memory reserved for the RMP table does not cover full system RAM (expected 0x%llx got 0x%llx)\n",
calc_rmp_sz, rmp_sz);
return false;
}
probed_rmp_base = rmp_base;
probed_rmp_size = rmp_sz;
pr_info("RMP table physical range [0x%016llx - 0x%016llx]\n",
probed_rmp_base, probed_rmp_base + probed_rmp_size - 1);
rmp_base, rmp_end);
return true;
}
@ -206,9 +189,8 @@ void __init snp_fixup_e820_tables(void)
*/
static int __init snp_rmptable_init(void)
{
u64 max_rmp_pfn, calc_rmp_sz, rmptable_size, rmp_end, val;
void *rmptable_start;
u64 rmptable_size;
u64 val;
if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return 0;
@ -219,10 +201,28 @@ static int __init snp_rmptable_init(void)
if (!probed_rmp_size)
goto nosnp;
rmp_end = probed_rmp_base + probed_rmp_size - 1;
/*
* Calculate the amount the memory that must be reserved by the BIOS to
* address the whole RAM, including the bookkeeping area. The RMP itself
* must also be covered.
*/
max_rmp_pfn = max_pfn;
if (PFN_UP(rmp_end) > max_pfn)
max_rmp_pfn = PFN_UP(rmp_end);
calc_rmp_sz = (max_rmp_pfn << 4) + RMPTABLE_CPU_BOOKKEEPING_SZ;
if (calc_rmp_sz > probed_rmp_size) {
pr_err("Memory reserved for the RMP table does not cover full system RAM (expected 0x%llx got 0x%llx)\n",
calc_rmp_sz, probed_rmp_size);
goto nosnp;
}
rmptable_start = memremap(probed_rmp_base, probed_rmp_size, MEMREMAP_WB);
if (!rmptable_start) {
pr_err("Failed to map RMP table\n");
return 1;
goto nosnp;
}
/*

211
drivers/virt/coco/sev-guest/sev-guest.c
View file

@ -2,7 +2,7 @@
/*
* AMD Secure Encrypted Virtualization (SEV) guest driver interface
*
* Copyright (C) 2021 Advanced Micro Devices, Inc.
* Copyright (C) 2021-2024 Advanced Micro Devices, Inc.
*
* Author: Brijesh Singh <brijesh.singh@amd.com>
*/
@ -23,6 +23,7 @@
#include <linux/sockptr.h>
#include <linux/cleanup.h>
#include <linux/uuid.h>
#include <linux/configfs.h>
#include <uapi/linux/sev-guest.h>
#include <uapi/linux/psp-sev.h>
@ -38,6 +39,8 @@
#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
#define SNP_REQ_RETRY_DELAY (2*HZ)
#define SVSM_MAX_RETRIES 3
struct snp_guest_crypto {
struct crypto_aead *tfm;
u8 *iv, *authtag;
@ -70,8 +73,15 @@ struct snp_guest_dev {
u8 *vmpck;
};
static u32 vmpck_id;
module_param(vmpck_id, uint, 0444);
/*
* The VMPCK ID represents the key used by the SNP guest to communicate with the
* SEV firmware in the AMD Secure Processor (ASP, aka PSP). By default, the key
* used will be the key associated with the VMPL at which the guest is running.
* Should the default key be wiped (see snp_disable_vmpck()), this parameter
* allows for using one of the remaining VMPCKs.
*/
static int vmpck_id = -1;
module_param(vmpck_id, int, 0444);
MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
/* Mutex to serialize the shared buffer access and command handling. */
@ -783,6 +793,143 @@ struct snp_msg_cert_entry {
u32 length;
};
static int sev_svsm_report_new(struct tsm_report *report, void *data)
{
unsigned int rep_len, man_len, certs_len;
struct tsm_desc *desc = &report->desc;
struct svsm_attest_call ac = {};
unsigned int retry_count;
void *rep, *man, *certs;
struct svsm_call call;
unsigned int size;
bool try_again;
void *buffer;
u64 call_id;
int ret;
/*
* Allocate pages for the request:
* - Report blob (4K)
* - Manifest blob (4K)
* - Certificate blob (16K)
*
* Above addresses must be 4K aligned
*/
rep_len = SZ_4K;
man_len = SZ_4K;
certs_len = SEV_FW_BLOB_MAX_SIZE;
guard(mutex)(&snp_cmd_mutex);
if (guid_is_null(&desc->service_guid)) {
call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SERVICES);
} else {
export_guid(ac.service_guid, &desc->service_guid);
ac.service_manifest_ver = desc->service_manifest_version;
call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SINGLE_SERVICE);
}
retry_count = 0;
retry:
memset(&call, 0, sizeof(call));
size = rep_len + man_len + certs_len;
buffer = alloc_pages_exact(size, __GFP_ZERO);
if (!buffer)
return -ENOMEM;
rep = buffer;
ac.report_buf.pa = __pa(rep);
ac.report_buf.len = rep_len;
man = rep + rep_len;
ac.manifest_buf.pa = __pa(man);
ac.manifest_buf.len = man_len;
certs = man + man_len;
ac.certificates_buf.pa = __pa(certs);
ac.certificates_buf.len = certs_len;
ac.nonce.pa = __pa(desc->inblob);
ac.nonce.len = desc->inblob_len;
ret = snp_issue_svsm_attest_req(call_id, &call, &ac);
if (ret) {
free_pages_exact(buffer, size);
switch (call.rax_out) {
case SVSM_ERR_INVALID_PARAMETER:
try_again = false;
if (ac.report_buf.len > rep_len) {
rep_len = PAGE_ALIGN(ac.report_buf.len);
try_again = true;
}
if (ac.manifest_buf.len > man_len) {
man_len = PAGE_ALIGN(ac.manifest_buf.len);
try_again = true;
}
if (ac.certificates_buf.len > certs_len) {
certs_len = PAGE_ALIGN(ac.certificates_buf.len);
try_again = true;
}
/* If one of the buffers wasn't large enough, retry the request */
if (try_again && retry_count < SVSM_MAX_RETRIES) {
retry_count++;
goto retry;
}
return -EINVAL;
default:
pr_err_ratelimited("SVSM attestation request failed (%d / 0x%llx)\n",
ret, call.rax_out);
return -EINVAL;
}
}
/*
* Allocate all the blob memory buffers at once so that the cleanup is
* done for errors that occur after the first allocation (i.e. before
* using no_free_ptr()).
*/
rep_len = ac.report_buf.len;
void *rbuf __free(kvfree) = kvzalloc(rep_len, GFP_KERNEL);
man_len = ac.manifest_buf.len;
void *mbuf __free(kvfree) = kvzalloc(man_len, GFP_KERNEL);
certs_len = ac.certificates_buf.len;
void *cbuf __free(kvfree) = certs_len ? kvzalloc(certs_len, GFP_KERNEL) : NULL;
if (!rbuf || !mbuf || (certs_len && !cbuf)) {
free_pages_exact(buffer, size);
return -ENOMEM;
}
memcpy(rbuf, rep, rep_len);
report->outblob = no_free_ptr(rbuf);
report->outblob_len = rep_len;
memcpy(mbuf, man, man_len);
report->manifestblob = no_free_ptr(mbuf);
report->manifestblob_len = man_len;
if (certs_len) {
memcpy(cbuf, certs, certs_len);
report->auxblob = no_free_ptr(cbuf);
report->auxblob_len = certs_len;
}
free_pages_exact(buffer, size);
return 0;
}
static int sev_report_new(struct tsm_report *report, void *data)
{
struct snp_msg_cert_entry *cert_table;
@ -797,6 +944,13 @@ static int sev_report_new(struct tsm_report *report, void *data)
if (desc->inblob_len != SNP_REPORT_USER_DATA_SIZE)
return -EINVAL;
if (desc->service_provider) {
if (strcmp(desc->service_provider, "svsm"))
return -EINVAL;
return sev_svsm_report_new(report, data);
}
void *buf __free(kvfree) = kvzalloc(size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@ -885,9 +1039,42 @@ static int sev_report_new(struct tsm_report *report, void *data)
return 0;
}
static const struct tsm_ops sev_tsm_ops = {
static bool sev_report_attr_visible(int n)
{
switch (n) {
case TSM_REPORT_GENERATION:
case TSM_REPORT_PROVIDER:
case TSM_REPORT_PRIVLEVEL:
case TSM_REPORT_PRIVLEVEL_FLOOR:
return true;
case TSM_REPORT_SERVICE_PROVIDER:
case TSM_REPORT_SERVICE_GUID:
case TSM_REPORT_SERVICE_MANIFEST_VER:
return snp_vmpl;
}
return false;
}
static bool sev_report_bin_attr_visible(int n)
{
switch (n) {
case TSM_REPORT_INBLOB:
case TSM_REPORT_OUTBLOB:
case TSM_REPORT_AUXBLOB:
return true;
case TSM_REPORT_MANIFESTBLOB:
return snp_vmpl;
}
return false;
}
static struct tsm_ops sev_tsm_ops = {
.name = KBUILD_MODNAME,
.report_new = sev_report_new,
.report_attr_visible = sev_report_attr_visible,
.report_bin_attr_visible = sev_report_bin_attr_visible,
};
static void unregister_sev_tsm(void *data)
@ -923,6 +1110,10 @@ static int __init sev_guest_probe(struct platform_device *pdev)
if (!snp_dev)
goto e_unmap;
/* Adjust the default VMPCK key based on the executing VMPL level */
if (vmpck_id == -1)
vmpck_id = snp_vmpl;
ret = -EINVAL;
snp_dev->vmpck = get_vmpck(vmpck_id, secrets, &snp_dev->os_area_msg_seqno);
if (!snp_dev->vmpck) {
@ -968,7 +1159,10 @@ static int __init sev_guest_probe(struct platform_device *pdev)
snp_dev->input.resp_gpa = __pa(snp_dev->response);
snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type);
/* Set the privlevel_floor attribute based on the vmpck_id */
sev_tsm_ops.privlevel_floor = vmpck_id;
ret = tsm_register(&sev_tsm_ops, snp_dev);
if (ret)
goto e_free_cert_data;
@ -1009,8 +1203,13 @@ static void __exit sev_guest_remove(struct platform_device *pdev)
* This driver is meant to be a common SEV guest interface driver and to
* support any SEV guest API. As such, even though it has been introduced
* with the SEV-SNP support, it is named "sev-guest".
*
* sev_guest_remove() lives in .exit.text. For drivers registered via
* module_platform_driver_probe() this is ok because they cannot get unbound
* at runtime. So mark the driver struct with __refdata to prevent modpost
* triggering a section mismatch warning.
*/
static struct platform_driver sev_guest_driver = {
static struct platform_driver sev_guest_driver __refdata = {
.remove_new = __exit_p(sev_guest_remove),
.driver = {
.name = "sev-guest",

26
drivers/virt/coco/tdx-guest/tdx-guest.c
View file

@ -249,6 +249,28 @@ done:
return ret;
}
static bool tdx_report_attr_visible(int n)
{
switch (n) {
case TSM_REPORT_GENERATION:
case TSM_REPORT_PROVIDER:
return true;
}
return false;
}
static bool tdx_report_bin_attr_visible(int n)
{
switch (n) {
case TSM_REPORT_INBLOB:
case TSM_REPORT_OUTBLOB:
return true;
}
return false;
}
static long tdx_guest_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@ -281,6 +303,8 @@ MODULE_DEVICE_TABLE(x86cpu, tdx_guest_ids);
static const struct tsm_ops tdx_tsm_ops = {
.name = KBUILD_MODNAME,
.report_new = tdx_report_new,
.report_attr_visible = tdx_report_attr_visible,
.report_bin_attr_visible = tdx_report_bin_attr_visible,
};
static int __init tdx_guest_init(void)
@ -301,7 +325,7 @@ static int __init tdx_guest_init(void)
goto free_misc;
}
ret = tsm_register(&tdx_tsm_ops, NULL, NULL);
ret = tsm_register(&tdx_tsm_ops, NULL);
if (ret)
goto free_quote;

177
drivers/virt/coco/tsm.c
View file

@ -14,7 +14,6 @@
static struct tsm_provider {
const struct tsm_ops *ops;
const struct config_item_type *type;
void *data;
} provider;
static DECLARE_RWSEM(tsm_rwsem);
@ -35,7 +34,7 @@ static DECLARE_RWSEM(tsm_rwsem);
* The attestation report format is TSM provider specific, when / if a standard
* materializes that can be published instead of the vendor layout. Until then
* the 'provider' attribute indicates the format of 'outblob', and optionally
* 'auxblob'.
* 'auxblob' and 'manifestblob'.
*/
struct tsm_report_state {
@ -48,6 +47,7 @@ struct tsm_report_state {
enum tsm_data_select {
TSM_REPORT,
TSM_CERTS,
TSM_MANIFEST,
};
static struct tsm_report *to_tsm_report(struct config_item *cfg)
@ -119,6 +119,74 @@ static ssize_t tsm_report_privlevel_floor_show(struct config_item *cfg,
}
CONFIGFS_ATTR_RO(tsm_report_, privlevel_floor);
static ssize_t tsm_report_service_provider_store(struct config_item *cfg,
const char *buf, size_t len)
{
struct tsm_report *report = to_tsm_report(cfg);
size_t sp_len;
char *sp;
int rc;
guard(rwsem_write)(&tsm_rwsem);
rc = try_advance_write_generation(report);
if (rc)
return rc;
sp_len = (buf[len - 1] != '\n') ? len : len - 1;
sp = kstrndup(buf, sp_len, GFP_KERNEL);
if (!sp)
return -ENOMEM;
kfree(report->desc.service_provider);
report->desc.service_provider = sp;
return len;
}
CONFIGFS_ATTR_WO(tsm_report_, service_provider);
static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
const char *buf, size_t len)
{
struct tsm_report *report = to_tsm_report(cfg);
int rc;
guard(rwsem_write)(&tsm_rwsem);
rc = try_advance_write_generation(report);
if (rc)
return rc;
report->desc.service_guid = guid_null;
rc = guid_parse(buf, &report->desc.service_guid);
if (rc)
return rc;
return len;
}
CONFIGFS_ATTR_WO(tsm_report_, service_guid);
static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg,
const char *buf, size_t len)
{
struct tsm_report *report = to_tsm_report(cfg);
unsigned int val;
int rc;
rc = kstrtouint(buf, 0, &val);
if (rc)
return rc;
guard(rwsem_write)(&tsm_rwsem);
rc = try_advance_write_generation(report);
if (rc)
return rc;
report->desc.service_manifest_version = val;
return len;
}
CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version);
static ssize_t tsm_report_inblob_write(struct config_item *cfg,
const void *buf, size_t count)
{
@ -163,6 +231,9 @@ static ssize_t __read_report(struct tsm_report *report, void *buf, size_t count,
if (select == TSM_REPORT) {
out = report->outblob;
len = report->outblob_len;
} else if (select == TSM_MANIFEST) {
out = report->manifestblob;
len = report->manifestblob_len;
} else {
out = report->auxblob;
len = report->auxblob_len;
@ -188,7 +259,7 @@ static ssize_t read_cached_report(struct tsm_report *report, void *buf,
/*
* A given TSM backend always fills in ->outblob regardless of
* whether the report includes an auxblob or not.
* whether the report includes an auxblob/manifestblob or not.
*/
if (!report->outblob ||
state->read_generation != state->write_generation)
@ -224,8 +295,10 @@ static ssize_t tsm_report_read(struct tsm_report *report, void *buf,
kvfree(report->outblob);
kvfree(report->auxblob);
kvfree(report->manifestblob);
report->outblob = NULL;
report->auxblob = NULL;
report->manifestblob = NULL;
rc = ops->report_new(report, provider.data);
if (rc < 0)
return rc;
@ -252,34 +325,31 @@ static ssize_t tsm_report_auxblob_read(struct config_item *cfg, void *buf,
}
CONFIGFS_BIN_ATTR_RO(tsm_report_, auxblob, NULL, TSM_OUTBLOB_MAX);
#define TSM_DEFAULT_ATTRS() \
&tsm_report_attr_generation, \
&tsm_report_attr_provider
static ssize_t tsm_report_manifestblob_read(struct config_item *cfg, void *buf,
size_t count)
{
struct tsm_report *report = to_tsm_report(cfg);
return tsm_report_read(report, buf, count, TSM_MANIFEST);
}
CONFIGFS_BIN_ATTR_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX);
static struct configfs_attribute *tsm_report_attrs[] = {
TSM_DEFAULT_ATTRS(),
[TSM_REPORT_GENERATION] = &tsm_report_attr_generation,
[TSM_REPORT_PROVIDER] = &tsm_report_attr_provider,
[TSM_REPORT_PRIVLEVEL] = &tsm_report_attr_privlevel,
[TSM_REPORT_PRIVLEVEL_FLOOR] = &tsm_report_attr_privlevel_floor,
[TSM_REPORT_SERVICE_PROVIDER] = &tsm_report_attr_service_provider,
[TSM_REPORT_SERVICE_GUID] = &tsm_report_attr_service_guid,
[TSM_REPORT_SERVICE_MANIFEST_VER] = &tsm_report_attr_service_manifest_version,
NULL,
};
static struct configfs_attribute *tsm_report_extra_attrs[] = {
TSM_DEFAULT_ATTRS(),
&tsm_report_attr_privlevel,
&tsm_report_attr_privlevel_floor,
NULL,
};
#define TSM_DEFAULT_BIN_ATTRS() \
&tsm_report_attr_inblob, \
&tsm_report_attr_outblob
static struct configfs_bin_attribute *tsm_report_bin_attrs[] = {
TSM_DEFAULT_BIN_ATTRS(),
NULL,
};
static struct configfs_bin_attribute *tsm_report_bin_extra_attrs[] = {
TSM_DEFAULT_BIN_ATTRS(),
&tsm_report_attr_auxblob,
[TSM_REPORT_INBLOB] = &tsm_report_attr_inblob,
[TSM_REPORT_OUTBLOB] = &tsm_report_attr_outblob,
[TSM_REPORT_AUXBLOB] = &tsm_report_attr_auxblob,
[TSM_REPORT_MANIFESTBLOB] = &tsm_report_attr_manifestblob,
NULL,
};
@ -288,8 +358,10 @@ static void tsm_report_item_release(struct config_item *cfg)
struct tsm_report *report = to_tsm_report(cfg);
struct tsm_report_state *state = to_state(report);
kvfree(report->manifestblob);
kvfree(report->auxblob);
kvfree(report->outblob);
kfree(report->desc.service_provider);
kfree(state);
}
@ -297,21 +369,44 @@ static struct configfs_item_operations tsm_report_item_ops = {
.release = tsm_report_item_release,
};
const struct config_item_type tsm_report_default_type = {
static bool tsm_report_is_visible(struct config_item *item,
struct configfs_attribute *attr, int n)
{
guard(rwsem_read)(&tsm_rwsem);
if (!provider.ops)
return false;
if (!provider.ops->report_attr_visible)
return true;
return provider.ops->report_attr_visible(n);
}
static bool tsm_report_is_bin_visible(struct config_item *item,
struct configfs_bin_attribute *attr, int n)
{
guard(rwsem_read)(&tsm_rwsem);
if (!provider.ops)
return false;
if (!provider.ops->report_bin_attr_visible)
return true;
return provider.ops->report_bin_attr_visible(n);
}
static struct configfs_group_operations tsm_report_attr_group_ops = {
.is_visible = tsm_report_is_visible,
.is_bin_visible = tsm_report_is_bin_visible,
};
static const struct config_item_type tsm_report_type = {
.ct_owner = THIS_MODULE,
.ct_bin_attrs = tsm_report_bin_attrs,
.ct_attrs = tsm_report_attrs,
.ct_item_ops = &tsm_report_item_ops,
.ct_group_ops = &tsm_report_attr_group_ops,
};
EXPORT_SYMBOL_GPL(tsm_report_default_type);
const struct config_item_type tsm_report_extra_type = {
.ct_owner = THIS_MODULE,
.ct_bin_attrs = tsm_report_bin_extra_attrs,
.ct_attrs = tsm_report_extra_attrs,
.ct_item_ops = &tsm_report_item_ops,
};
EXPORT_SYMBOL_GPL(tsm_report_extra_type);
static struct config_item *tsm_report_make_item(struct config_group *group,
const char *name)
@ -326,7 +421,7 @@ static struct config_item *tsm_report_make_item(struct config_group *group,
if (!state)
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&state->cfg, name, provider.type);
config_item_init_type_name(&state->cfg, name, &tsm_report_type);
return &state->cfg;
}
@ -353,16 +448,10 @@ static struct configfs_subsystem tsm_configfs = {
.su_mutex = __MUTEX_INITIALIZER(tsm_configfs.su_mutex),
};
int tsm_register(const struct tsm_ops *ops, void *priv,
const struct config_item_type *type)
int tsm_register(const struct tsm_ops *ops, void *priv)
{
const struct tsm_ops *conflict;
if (!type)
type = &tsm_report_default_type;
if (!(type == &tsm_report_default_type || type == &tsm_report_extra_type))
return -EINVAL;
guard(rwsem_write)(&tsm_rwsem);
conflict = provider.ops;
if (conflict) {
@ -372,7 +461,6 @@ int tsm_register(const struct tsm_ops *ops, void *priv,
provider.ops = ops;
provider.data = priv;
provider.type = type;
return 0;
}
EXPORT_SYMBOL_GPL(tsm_register);
@ -384,7 +472,6 @@ int tsm_unregister(const struct tsm_ops *ops)
return -EBUSY;
provider.ops = NULL;
provider.data = NULL;
provider.type = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(tsm_unregister);

10
fs/configfs/dir.c
View file

@ -580,6 +580,7 @@ static void detach_attrs(struct config_item * item)
static int populate_attrs(struct config_item *item)
{
const struct config_item_type *t = item->ci_type;
struct configfs_group_operations *ops;
struct configfs_attribute *attr;
struct configfs_bin_attribute *bin_attr;
int error = 0;
@ -587,14 +588,23 @@ static int populate_attrs(struct config_item *item)
if (!t)
return -EINVAL;
ops = t->ct_group_ops;
if (t->ct_attrs) {
for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
if (ops && ops->is_visible && !ops->is_visible(item, attr, i))
continue;
if ((error = configfs_create_file(item, attr)))
break;
}
}
if (t->ct_bin_attrs) {
for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) {
if (ops && ops->is_bin_visible && !ops->is_bin_visible(item, bin_attr, i))
continue;
error = configfs_create_bin_file(item, bin_attr);
if (error)
break;

3
include/linux/configfs.h
View file

@ -216,6 +216,9 @@ struct configfs_group_operations {
struct config_group *(*make_group)(struct config_group *group, const char *name);
void (*disconnect_notify)(struct config_group *group, struct config_item *item);
void (*drop_item)(struct config_group *group, struct config_item *item);
bool (*is_visible)(struct config_item *item, struct configfs_attribute *attr, int n);
bool (*is_bin_visible)(struct config_item *item, struct configfs_bin_attribute *attr,
int n);
};
struct configfs_subsystem {

59
include/linux/tsm.h
View file

@ -4,6 +4,7 @@
#include <linux/sizes.h>
#include <linux/types.h>
#include <linux/uuid.h>
#define TSM_INBLOB_MAX 64
#define TSM_OUTBLOB_MAX SZ_32K
@ -19,11 +20,17 @@
* @privlevel: optional privilege level to associate with @outblob
* @inblob_len: sizeof @inblob
* @inblob: arbitrary input data
* @service_provider: optional name of where to obtain the tsm report blob
* @service_guid: optional service-provider service guid to attest
* @service_manifest_version: optional service-provider service manifest version requested
*/
struct tsm_desc {
unsigned int privlevel;
size_t inblob_len;
u8 inblob[TSM_INBLOB_MAX];
char *service_provider;
guid_t service_guid;
unsigned int service_manifest_version;
};
/**
@ -33,6 +40,8 @@ struct tsm_desc {
* @outblob: generated evidence to provider to the attestation agent
* @auxblob_len: sizeof(@auxblob)
* @auxblob: (optional) auxiliary data to the report (e.g. certificate data)
* @manifestblob_len: sizeof(@manifestblob)
* @manifestblob: (optional) manifest data associated with the report
*/
struct tsm_report {
struct tsm_desc desc;
@ -40,6 +49,42 @@ struct tsm_report {
u8 *outblob;
size_t auxblob_len;
u8 *auxblob;
size_t manifestblob_len;
u8 *manifestblob;
};
/**
* enum tsm_attr_index - index used to reference report attributes
* @TSM_REPORT_GENERATION: index of the report generation number attribute
* @TSM_REPORT_PROVIDER: index of the provider name attribute
* @TSM_REPORT_PRIVLEVEL: index of the desired privilege level attribute
* @TSM_REPORT_PRIVLEVEL_FLOOR: index of the minimum allowed privileg level attribute
* @TSM_REPORT_SERVICE_PROVIDER: index of the service provider identifier attribute
* @TSM_REPORT_SERVICE_GUID: index of the service GUID attribute
* @TSM_REPORT_SERVICE_MANIFEST_VER: index of the service manifest version attribute
*/
enum tsm_attr_index {
TSM_REPORT_GENERATION,
TSM_REPORT_PROVIDER,
TSM_REPORT_PRIVLEVEL,
TSM_REPORT_PRIVLEVEL_FLOOR,
TSM_REPORT_SERVICE_PROVIDER,
TSM_REPORT_SERVICE_GUID,
TSM_REPORT_SERVICE_MANIFEST_VER,
};
/**
* enum tsm_bin_attr_index - index used to reference binary report attributes
* @TSM_REPORT_INBLOB: index of the binary report input attribute
* @TSM_REPORT_OUTBLOB: index of the binary report output attribute
* @TSM_REPORT_AUXBLOB: index of the binary auxiliary data attribute
* @TSM_REPORT_MANIFESTBLOB: index of the binary manifest data attribute
*/
enum tsm_bin_attr_index {
TSM_REPORT_INBLOB,
TSM_REPORT_OUTBLOB,
TSM_REPORT_AUXBLOB,
TSM_REPORT_MANIFESTBLOB,
};
/**
@ -48,22 +93,20 @@ struct tsm_report {
* @privlevel_floor: convey base privlevel for nested scenarios
* @report_new: Populate @report with the report blob and auxblob
* (optional), return 0 on successful population, or -errno otherwise
* @report_attr_visible: show or hide a report attribute entry
* @report_bin_attr_visible: show or hide a report binary attribute entry
*
* Implementation specific ops, only one is expected to be registered at
* a time i.e. only one of "sev-guest", "tdx-guest", etc.
*/
struct tsm_ops {
const char *name;
const unsigned int privlevel_floor;
unsigned int privlevel_floor;
int (*report_new)(struct tsm_report *report, void *data);
bool (*report_attr_visible)(int n);
bool (*report_bin_attr_visible)(int n);
};
extern const struct config_item_type tsm_report_default_type;
/* publish @privlevel, @privlevel_floor, and @auxblob attributes */
extern const struct config_item_type tsm_report_extra_type;
int tsm_register(const struct tsm_ops *ops, void *priv,
const struct config_item_type *type);
int tsm_register(const struct tsm_ops *ops, void *priv);
int tsm_unregister(const struct tsm_ops *ops);
#endif /* __TSM_H */