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2024-10-06KVM: x86: leave kvm.ko out of the build if no vendor module is requestedPaolo Bonzini1-3/+6
kvm.ko is nothing but library code shared by kvm-intel.ko and kvm-amd.ko. It provides no functionality on its own and it is unnecessary unless one of the vendor-specific module is compiled. In particular, /dev/kvm is not created until one of kvm-intel.ko or kvm-amd.ko is loaded. Use CONFIG_KVM to decide if it is built-in or a module, but use the vendor-specific modules for the actual decision on whether to build it. This also fixes a build failure when CONFIG_KVM_INTEL and CONFIG_KVM_AMD are both disabled. The cpu_emergency_register_virt_callback() function is called from kvm.ko, but it is only defined if at least one of CONFIG_KVM_INTEL and CONFIG_KVM_AMD is provided. Fixes: 590b09b1d88e ("KVM: x86: Register "emergency disable" callbacks when virt is enabled") Signed-off-by: Paolo Bonzini <[email protected]>
2024-09-05KVM: Remove HIGH_RES_TIMERS dependencySteven Rostedt1-1/+0
Commit 92b5265d38f6a ("KVM: Depend on HIGH_RES_TIMERS") added a dependency to high resolution timers with the comment: KVM lapic timer and tsc deadline timer based on hrtimer, setting a leftmost node to rb tree and then do hrtimer reprogram. If hrtimer not configured as high resolution, hrtimer_enqueue_reprogram do nothing and then make kvm lapic timer and tsc deadline timer fail. That was back in 2012, where hrtimer_start_range_ns() would do the reprogramming with hrtimer_enqueue_reprogram(). But as that was a nop with high resolution timers disabled, this did not work. But a lot has changed in the last 12 years. For example, commit 49a2a07514a3a ("hrtimer: Kick lowres dynticks targets on timer enqueue") modifies __hrtimer_start_range_ns() to work with low res timers. There's been lots of other changes that make low res work. ChromeOS has tested this before as well, and it hasn't seen any issues with running KVM with high res timers disabled. There could be problems, especially at low HZ, for guests that do not support kvmclock and rely on precise delivery of periodic timers to keep their clock running. This can be the APIC timer (provided by the kernel), the RTC (provided by userspace), or the i8254 (choice of kernel/userspace). These guests are few and far between these days, and in the case of the APIC timer + Intel hosts we can use the preemption timer (which is TSC-based and has better latency _and_ accuracy). In KVM, only x86 is requiring CONFIG_HIGH_RES_TIMERS; perhaps a "depends on HIGH_RES_TIMERS || EXPERT" could be added to virt/kvm, or a pr_warn could be added to kvm_init if HIGH_RES_TIMERS are not enabled. But in general, it seems that there must be other code in the kernel (maybe sound/?) that is relying on having high-enough HZ or hrtimers but that's not documented anywhere. Whenever you disable it you probably need to know what you're doing and what your workload is; so the dependency is not particularly interesting, and we can just remove it. Signed-off-by: Steven Rostedt (Google) <[email protected]> Message-ID: <[email protected]> [Added the last two paragraphs to the commit message. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]>
2024-08-28KVM: SEV: Update KVM_AMD_SEV Kconfig entry and mention SEV-SNPVitaly Kuznetsov1-2/+4
SEV-SNP support is present since commit 1dfe571c12cf ("KVM: SEV: Add initial SEV-SNP support") but Kconfig entry wasn't updated and still mentions SEV and SEV-ES only. Add SEV-SNP there and, while on it, expand 'SEV' in the description as 'Encrypted VMs' is not what 'SEV' stands for. No functional change. Signed-off-by: Vitaly Kuznetsov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
2024-07-26KVM: rename CONFIG_HAVE_KVM_GMEM_* to CONFIG_HAVE_KVM_ARCH_GMEM_*Paolo Bonzini1-2/+2
Add "ARCH" to the symbols; shortly, the "prepare" phase will include both the arch-independent step to clear out contents left in the page by the host, and the arch-dependent step enabled by CONFIG_HAVE_KVM_GMEM_PREPARE. For consistency do the same for CONFIG_HAVE_KVM_GMEM_INVALIDATE as well. Reviewed-by: Michael Roth <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-07-12KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()Paolo Bonzini1-0/+1
Wire KVM_PRE_FAULT_MEMORY ioctl to kvm_mmu_do_page_fault() to populate guest memory. It can be called right after KVM_CREATE_VCPU creates a vCPU, since at that point kvm_mmu_create() and kvm_init_mmu() are called and the vCPU is ready to invoke the KVM page fault handler. The helper function kvm_tdp_map_page() takes care of the logic to process RET_PF_* return values and convert them to success or errno. Signed-off-by: Isaku Yamahata <[email protected]> Message-ID: <9b866a0ae7147f96571c439e75429a03dcb659b6.1712785629.git.isaku.yamahata@intel.com> Signed-off-by: Paolo Bonzini <[email protected]>
2024-06-03Merge branch 'kvm-6.11-sev-snp' into HEADPaolo Bonzini1-0/+3
Pull base x86 KVM support for running SEV-SNP guests from Michael Roth: * add some basic infrastructure and introduces a new KVM_X86_SNP_VM vm_type to handle differences versus the existing KVM_X86_SEV_VM and KVM_X86_SEV_ES_VM types. * implement the KVM API to handle the creation of a cryptographic launch context, encrypt/measure the initial image into guest memory, and finalize it before launching it. * implement handling for various guest-generated events such as page state changes, onlining of additional vCPUs, etc. * implement the gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges as well as cleaning them up prior to returning them to the host for use as normal memory. Because those cleanup hooks supplant certain activities like issuing WBINVDs during KVM MMU invalidations, avoid duplicating that work to avoid unecessary overhead. This merge leaves out support support for attestation guest requests and for loading the signing keys to be used for attestation requests.
2024-05-23KVM: x86: Force KVM_WERROR if the global WERROR is enabledSean Christopherson1-1/+2
Force KVM_WERROR if the global WERROR is enabled to avoid pestering the user about a Kconfig that will ultimately be ignored. Force KVM_WERROR instead of making it mutually exclusive with WERROR to avoid generating a .config builds KVM with -Werror, but has KVM_WERROR=n. Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-05-23KVM: x86: Disable KVM_INTEL_PROVE_VE by defaultSean Christopherson1-3/+5
Disable KVM's "prove #VE" support by default, as it provides no functional value, and even its sanity checking benefits are relatively limited. I.e. it should be fully opt-in even on debug kernels, especially since EPT Violation #VE suppression appears to be buggy on some CPUs. Opportunistically add a line in the help text to make it abundantly clear that KVM_INTEL_PROVE_VE should never be enabled in a production environment. Suggested-by: Paolo Bonzini <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-05-12KVM: SEV: Implement gmem hook for invalidating private pagesMichael Roth1-0/+1
Implement a platform hook to do the work of restoring the direct map entries of gmem-managed pages and transitioning the corresponding RMP table entries back to the default shared/hypervisor-owned state. Signed-off-by: Michael Roth <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-05-12KVM: SEV: Implement gmem hook for initializing private pagesMichael Roth1-0/+1
This will handle the RMP table updates needed to put a page into a private state before mapping it into an SEV-SNP guest. Reviewed-by: Paolo Bonzini <[email protected]> Signed-off-by: Michael Roth <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-05-12KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=yMichael Roth1-0/+1
SEV-SNP relies on private memory support to run guests, so make sure to enable that support via the CONFIG_KVM_GENERIC_PRIVATE_MEM config option. Signed-off-by: Michael Roth <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2024-04-19KVM: VMX: Introduce test mode related to EPT violation VEIsaku Yamahata1-0/+13
To support TDX, KVM is enhanced to operate with #VE. For TDX, KVM uses the suppress #VE bit in EPT entries selectively, in order to be able to trap non-present conditions. However, #VE isn't used for VMX and it's a bug if it happens. To be defensive and test that VMX case isn't broken introduce an option ept_violation_ve_test and when it's set, BUG the vm. Suggested-by: Paolo Bonzini <[email protected]> Signed-off-by: Isaku Yamahata <[email protected]> Message-Id: <d6db6ba836605c0412e166359ba5c46a63c22f86.1705965635.git.isaku.yamahata@intel.com> Signed-off-by: Paolo Bonzini <[email protected]>
2024-04-04x86/kvm/Kconfig: Have KVM_AMD_SEV select ARCH_HAS_CC_PLATFORMBorislav Petkov (AMD)1-0/+1
The functionality to load SEV-SNP guests by the host will soon rely on cc_platform* helpers because the cpu_feature* API with the early patching is insufficient when SNP support needs to be disabled late. Therefore, pull that functionality in. Fixes: 216d106c7ff7 ("x86/sev: Add SEV-SNP host initialization support") Signed-off-by: Borislav Petkov (AMD) <[email protected]> Reviewed-by: Tom Lendacky <[email protected]> Tested-by: Srikanth Aithal <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2024-03-21Merge tag 'kbuild-v6.9' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Generate a list of built DTB files (arch/*/boot/dts/dtbs-list) - Use more threads when building Debian packages in parallel - Fix warnings shown during the RPM kernel package uninstallation - Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to Makefile - Support GCC's -fmin-function-alignment flag - Fix a null pointer dereference bug in modpost - Add the DTB support to the RPM package - Various fixes and cleanups in Kconfig * tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (67 commits) kconfig: tests: test dependency after shuffling choices kconfig: tests: add a test for randconfig with dependent choices kconfig: tests: support KCONFIG_SEED for the randconfig runner kbuild: rpm-pkg: add dtb files in kernel rpm kconfig: remove unneeded menu_is_visible() call in conf_write_defconfig() kconfig: check prompt for choice while parsing kconfig: lxdialog: remove unused dialog colors kconfig: lxdialog: fix button color for blackbg theme modpost: fix null pointer dereference kbuild: remove GCC's default -Wpacked-bitfield-compat flag kbuild: unexport abs_srctree and abs_objtree kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 kconfig: remove named choice support kconfig: use linked list in get_symbol_str() to iterate over menus kconfig: link menus to a symbol kbuild: fix inconsistent indentation in top Makefile kbuild: Use -fmin-function-alignment when available alpha: merge two entries for CONFIG_ALPHA_GAMMA alpha: merge two entries for CONFIG_ALPHA_EV4 kbuild: change DTC_FLAGS_<basetarget>.o to take the path relative to $(obj) ...
2024-03-09Merge tag 'kvm-x86-guest_memfd_fixes-6.8' of ↵Paolo Bonzini1-3/+4
https://github.com/kvm-x86/linux into HEAD KVM GUEST_MEMFD fixes for 6.8: - Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY to avoid creating ABI that KVM can't sanely support. - Update documentation for KVM_SW_PROTECTED_VM to make it abundantly clear that such VMs are purely a development and testing vehicle, and come with zero guarantees. - Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term plan is to support confidential VMs with deterministic private memory (SNP and TDX) only in the TDP MMU. - Fix a bug in a GUEST_MEMFD negative test that resulted in false passes when verifying that KVM_MEM_GUEST_MEMFD memslots can't be dirty logged.
2024-02-22KVM: x86: Update KVM_SW_PROTECTED_VM docs to make it clear they're a WIPSean Christopherson1-3/+4
Rewrite the help message for KVM_SW_PROTECTED_VM to make it clear that software-protected VMs are a development and testing vehicle for guest_memfd(), and that attempting to use KVM_SW_PROTECTED_VM for anything remotely resembling a "real" VM will fail. E.g. any memory accesses from KVM will incorrectly access shared memory, nested TDP is wildly broken, and so on and so forth. Update KVM's API documentation with similar warnings to discourage anyone from attempting to run anything but selftests with KVM_X86_SW_PROTECTED_VM. Fixes: 89ea60c2c7b5 ("KVM: x86: Add support for "protected VMs" that can utilize private memory") Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
2024-02-20treewide: replace or remove redundant def_bool in Kconfig filesMasahiro Yamada1-1/+1
'def_bool X' is a shorthand for 'bool' plus 'default X'. 'def_bool' is redundant where 'bool' is already present, so 'def_bool X' can be replaced with 'default X', or removed if X is 'n'. Signed-off-by: Masahiro Yamada <[email protected]>
2024-02-08Merge branch 'kvm-kconfig'Paolo Bonzini1-3/+0
Cleanups to Kconfig definitions for KVM * replace HAVE_KVM with an architecture-dependent symbol, when CONFIG_KVM may or may not be available depending on CPU capabilities (MIPS) * replace HAVE_KVM with IS_ENABLED(CONFIG_KVM) for host-side code that is not part of the KVM module, so that it is completely compiled out * factor common "select" statements in common code instead of requiring each architecture to specify it
2024-02-08treewide: remove CONFIG_HAVE_KVMPaolo Bonzini1-2/+0
It has no users anymore. Signed-off-by: Paolo Bonzini <[email protected]>
2024-02-08kvm: move "select IRQ_BYPASS_MANAGER" to common codePaolo Bonzini1-1/+0
CONFIG_IRQ_BYPASS_MANAGER is a dependency of the common code included by CONFIG_HAVE_KVM_IRQ_BYPASS. There is no advantage in adding the corresponding "select" directive to each architecture. Signed-off-by: Paolo Bonzini <[email protected]>
2024-02-08kvm: replace __KVM_HAVE_READONLY_MEM with Kconfig symbolPaolo Bonzini1-0/+1
KVM uses __KVM_HAVE_* symbols in the architecture-dependent uapi/asm/kvm.h to mask unused definitions in include/uapi/linux/kvm.h. __KVM_HAVE_READONLY_MEM however was nothing but a misguided attempt to define KVM_CAP_READONLY_MEM only on architectures where KVM_CHECK_EXTENSION(KVM_CAP_READONLY_MEM) could possibly return nonzero. This however does not make sense, and it prevented userspace from supporting this architecture-independent feature without recompilation. Therefore, these days __KVM_HAVE_READONLY_MEM does not mask anything and is only used in virt/kvm/kvm_main.c. Userspace does not need to test it and there should be no need for it to exist. Remove it and replace it with a Kconfig symbol within Linux source code. Signed-off-by: Paolo Bonzini <[email protected]>
2024-01-08Merge tag 'kvm-x86-misc-6.8' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini1-7/+7
KVM x86 misc changes for 6.8: - Turn off KVM_WERROR by default for all configs so that it's not inadvertantly enabled by non-KVM developers, which can be problematic for subsystems that require no regressions for W=1 builds. - Advertise all of the host-supported CPUID bits that enumerate IA32_SPEC_CTRL "features". - Don't force a masterclock update when a vCPU synchronizes to the current TSC generation, as updating the masterclock can cause kvmclock's time to "jump" unexpectedly, e.g. when userspace hotplugs a pre-created vCPU. - Use RIP-relative address to read kvm_rebooting in the VM-Enter fault paths, partly as a super minor optimization, but mostly to make KVM play nice with position independent executable builds.
2024-01-08Merge tag 'kvm-x86-hyperv-6.8' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini1-0/+14
KVM x86 Hyper-V changes for 6.8: - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on CONFIG_HYPERV as a minor optimization, and to self-document the code. - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV "emulation" at build time.
2024-01-08KVM: x86: add missing "depends on KVM"Paolo Bonzini1-1/+1
Support for KVM software-protected VMs should not be configurable, if KVM is not available at all. Fixes: 89ea60c2c7b5 ("KVM: x86: Add support for "protected VMs" that can utilize private memory") Signed-off-by: Paolo Bonzini <[email protected]>
2024-01-08KVM: introduce CONFIG_KVM_COMMONPaolo Bonzini1-2/+1
CONFIG_HAVE_KVM is currently used by some architectures to either enabled the KVM config proper, or to enable host-side code that is not part of the KVM module. However, CONFIG_KVM's "select" statement in virt/kvm/Kconfig corresponds to a third meaning, namely to enable common Kconfigs required by all architectures that support KVM. These three meanings can be replaced respectively by an architecture-specific Kconfig, by IS_ENABLED(CONFIG_KVM), or by a new Kconfig symbol that is in turn selected by the architecture-specific "config KVM". Start by introducing such a new Kconfig symbol, CONFIG_KVM_COMMON. Unlike CONFIG_HAVE_KVM, it is selected by CONFIG_KVM, not by architecture code, and it brings in all dependencies of common KVM code. In particular, INTERVAL_TREE was missing in loongarch and riscv, so that is another thing that is fixed. Fixes: 8132d887a702 ("KVM: remove CONFIG_HAVE_KVM_EVENTFD", 2023-12-08) Reported-by: Randy Dunlap <[email protected]> Closes: https://lore.kernel.org/all/[email protected]/ Reviewed-by: Andrew Jones <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2023-12-08KVM: remove CONFIG_HAVE_KVM_IRQFDPaolo Bonzini1-1/+0
All platforms with a kernel irqchip have support for irqfd. Unify the two configuration items so that userspace can expect to use irqfd to inject interrupts into the irqchip. Signed-off-by: Paolo Bonzini <[email protected]>
2023-12-08KVM: remove CONFIG_HAVE_KVM_EVENTFDPaolo Bonzini1-1/+0
virt/kvm/eventfd.c is compiled unconditionally, meaning that the ioeventfds member of struct kvm is accessed unconditionally. CONFIG_HAVE_KVM_EVENTFD therefore must be defined for KVM common code to compile successfully, remove it. Signed-off-by: Paolo Bonzini <[email protected]>
2023-12-07KVM: x86: Make Hyper-V emulation optionalVitaly Kuznetsov1-0/+14
Hyper-V emulation in KVM is a fairly big chunk and in some cases it may be desirable to not compile it in to reduce module sizes as well as the attack surface. Introduce CONFIG_KVM_HYPERV option to make it possible. Note, there's room for further nVMX/nSVM code optimizations when !CONFIG_KVM_HYPERV, this will be done in follow-up patches. Reorganize Makefile a bit so all CONFIG_HYPERV and CONFIG_KVM_HYPERV files are grouped together. Signed-off-by: Vitaly Kuznetsov <[email protected]> Reviewed-by: Maxim Levitsky <[email protected]> Tested-by: Jeremi Piotrowski <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
2023-11-30KVM: x86: Turn off KVM_WERROR by default for all configsSean Christopherson1-7/+7
Don't enable KVM_WERROR by default for x86-64 builds as KVM's one-off -Werror enabling is *mostly* superseded by the kernel-wide WERROR, and enabling KVM_WERROR by default can cause problems for developers working on other subsystems. E.g. subsystems that have a "zero W=1 regressions" rule can inadvertently build KVM with -Werror and W=1, and end up with build failures that are completely uninteresting to the developer (W=1 is prone to false positives, especially on older compilers). Keep KVM_WERROR as there are combinations where enabling WERROR isn't feasible, e.g. the default FRAME_WARN=1024 on i386 builds generates a non-zero number of warnings and thus errors, and there are far too many warnings throughout the kernel to enable WERROR with W=1 (building KVM with -Werror is desirable (with a sane compiler) as W=1 does generate useful warnings). Opportunistically drop the dependency on !COMPILE_TEST as it's completely meaningless (it was copied from i195's -Werror Kconfig), as the kernel's WERROR is explicitly *enabled* for COMPILE_TEST=y kernel's, i.e. enabling -Werror is obviosly not dependent on COMPILE_TEST=n. Reported-by: Jakub Kicinski <[email protected]> Link: https://lore.kernel.org/all/[email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
2023-11-14KVM: x86: Add support for "protected VMs" that can utilize private memorySean Christopherson1-0/+12
Add a new x86 VM type, KVM_X86_SW_PROTECTED_VM, to serve as a development and testing vehicle for Confidential (CoCo) VMs, and potentially to even become a "real" product in the distant future, e.g. a la pKVM. The private memory support in KVM x86 is aimed at AMD's SEV-SNP and Intel's TDX, but those technologies are extremely complex (understatement), difficult to debug, don't support running as nested guests, and require hardware that's isn't universally accessible. I.e. relying SEV-SNP or TDX for maintaining guest private memory isn't a realistic option. At the very least, KVM_X86_SW_PROTECTED_VM will enable a variety of selftests for guest_memfd and private memory support without requiring unique hardware. Signed-off-by: Sean Christopherson <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Message-Id: <[email protected]> Reviewed-by: Fuad Tabba <[email protected]> Tested-by: Fuad Tabba <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2023-11-13KVM: Convert KVM_ARCH_WANT_MMU_NOTIFIER to CONFIG_KVM_GENERIC_MMU_NOTIFIERSean Christopherson1-1/+1
Convert KVM_ARCH_WANT_MMU_NOTIFIER into a Kconfig and select it where appropriate to effectively maintain existing behavior. Using a proper Kconfig will simplify building more functionality on top of KVM's mmu_notifier infrastructure. Add a forward declaration of kvm_gfn_range to kvm_types.h so that including arch/powerpc/include/asm/kvm_ppc.h's with CONFIG_KVM=n doesn't generate warnings due to kvm_gfn_range being undeclared. PPC defines hooks for PR vs. HV without guarding them via #ifdeffery, e.g. bool (*unmap_gfn_range)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*test_age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*set_spte_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); Alternatively, PPC could forward declare kvm_gfn_range, but there's no good reason not to define it in common KVM. Acked-by: Anup Patel <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Reviewed-by: Fuad Tabba <[email protected]> Tested-by: Fuad Tabba <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2023-09-28KVM: x86: Add CONFIG_KVM_MAX_NR_VCPUS to allow up to 4096 vCPUsKyle Meyer1-0/+11
Add a Kconfig entry to set the maximum number of vCPUs per KVM guest and set the default value to 4096 when MAXSMP is enabled, as there are use cases that want to create more than the currently allowed 1024 vCPUs and are more than happy to eat the memory overhead. The Hyper-V TLFS doesn't allow more than 64 sparse banks, i.e. allows a maximum of 4096 virtual CPUs. Cap KVM's maximum number of virtual CPUs to 4096 to avoid exceeding Hyper-V's limit as KVM support for Hyper-V is unconditional, and alternatives like dynamically disabling Hyper-V enlightenments that rely on sparse banks would require non-trivial code changes. Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: Kyle Meyer <[email protected]> Link: https://lore.kernel.org/r/[email protected] [sean: massage changelog with --verbose, document #ifdef mess] Signed-off-by: Sean Christopherson <[email protected]>
2023-08-31KVM: x86/mmu: Replace MMU_DEBUG with proper KVM_PROVE_MMU KconfigSean Christopherson1-0/+13
Replace MMU_DEBUG, which requires manually modifying KVM to enable the macro, with a proper Kconfig, KVM_PROVE_MMU. Now that pgprintk() and rmap_printk() are gone, i.e. the macro guards only KVM_MMU_WARN_ON() and won't flood the kernel logs, enabling the option for debug kernels is both desirable and feasible. Reviewed-by: Philippe Mathieu-Daudé <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2023-08-03KVM: SVM: Make KVM_AMD depend on CPU_SUP_AMD or CPU_SUP_HYGONSean Christopherson1-1/+1
Make building KVM SVM support depend on support for AMD or Hygon. KVM already effectively restricts SVM support to AMD and Hygon by virtue of the vendor string checks in cpu_has_svm(), and KVM VMX supports depends on one of its three known vendors (Intel, Centaur, or Zhaoxin). Add the CPU_SUP_HYGON clause even though CPU_SUP_HYGON selects CPU_SUP_AMD to document that KVM SVM support isn't just for AMD CPUs, and to prevent breakage should Hygon support ever become a standalone thing. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
2023-04-05kvm: Remove "select SRCU"Paul E. McKenney1-1/+0
Now that the SRCU Kconfig option is unconditionally selected, there is no longer any point in selecting it. Therefore, remove the "select SRCU" Kconfig statements from the various KVM Kconfig files. Acked-by: Sean Christopherson <[email protected]> (x86) Signed-off-by: Paul E. McKenney <[email protected]> Cc: Huacai Chen <[email protected]> Cc: Aleksandar Markovic <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Christophe Leroy <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: <[email protected]> Acked-by: Marc Zyngier <[email protected]> (arm64) Acked-by: Michael Ellerman <[email protected]> (powerpc) Acked-by: Anup Patel <[email protected]> (riscv) Acked-by: Heiko Carstens <[email protected]> (s390) Reviewed-by: John Ogness <[email protected]> Signed-off-by: Joel Fernandes (Google) <[email protected]>
2022-12-29KVM: Opt out of generic hardware enabling on s390 and PPCSean Christopherson1-0/+1
Allow architectures to opt out of the generic hardware enabling logic, and opt out on both s390 and PPC, which don't need to manually enable virtualization as it's always on (when available). In addition to letting s390 and PPC drop a bit of dead code, this will hopefully also allow ARM to clean up its related code, e.g. ARM has its own per-CPU flag to track which CPUs have enable hardware due to the need to keep hardware enabled indefinitely when pKVM is enabled. Signed-off-by: Sean Christopherson <[email protected]> Acked-by: Anup Patel <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2022-11-09KVM: allow compiling out SMM supportPaolo Bonzini1-0/+11
Some users of KVM implement the UEFI variable store through a paravirtual device that does not require the "SMM lockbox" component of edk2; allow them to compile out system management mode, which is not a full implementation especially in how it interacts with nested virtualization. Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> Reviewed-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2022-09-29KVM: x86: Select CONFIG_HAVE_KVM_DIRTY_RING_ACQ_RELMarc Zyngier1-0/+1
Since x86 is TSO (give or take), allow it to advertise the new ACQ_REL version of the dirty ring capability. No other change is required for it. Signed-off-by: Marc Zyngier <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Reviewed-by: Peter Xu <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-09-29KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config optionMarc Zyngier1-1/+1
In order to differenciate between architectures that require no extra synchronisation when accessing the dirty ring and those who do, add a new capability (KVM_CAP_DIRTY_LOG_RING_ACQ_REL) that identify the latter sort. TSO architectures can obviously advertise both, while relaxed architectures must only advertise the ACQ_REL version. This requires some configuration symbol rejigging, with HAVE_KVM_DIRTY_RING being only indirectly selected by two top-level config symbols: - HAVE_KVM_DIRTY_RING_TSO for strongly ordered architectures (x86) - HAVE_KVM_DIRTY_RING_ACQ_REL for weakly ordered architectures (arm64) Suggested-by: Paolo Bonzini <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Reviewed-by: Peter Xu <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-02-18KVM: x86/mmu: Remove MMU auditingSean Christopherson1-7/+0
Remove mmu_audit.c and all its collateral, the auditing code has suffered severe bitrot, ironically partly due to shadow paging being more stable and thus not benefiting as much from auditing, but mostly due to TDP supplanting shadow paging for non-nested guests and shadowing of nested TDP not heavily stressing the logic that is being audited. Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2022-01-16Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+3
Pull kvm updates from Paolo Bonzini: "RISCV: - Use common KVM implementation of MMU memory caches - SBI v0.2 support for Guest - Initial KVM selftests support - Fix to avoid spurious virtual interrupts after clearing hideleg CSR - Update email address for Anup and Atish ARM: - Simplification of the 'vcpu first run' by integrating it into KVM's 'pid change' flow - Refactoring of the FP and SVE state tracking, also leading to a simpler state and less shared data between EL1 and EL2 in the nVHE case - Tidy up the header file usage for the nvhe hyp object - New HYP unsharing mechanism, finally allowing pages to be unmapped from the Stage-1 EL2 page-tables - Various pKVM cleanups around refcounting and sharing - A couple of vgic fixes for bugs that would trigger once the vcpu xarray rework is merged, but not sooner - Add minimal support for ARMv8.7's PMU extension - Rework kvm_pgtable initialisation ahead of the NV work - New selftest for IRQ injection - Teach selftests about the lack of default IPA space and page sizes - Expand sysreg selftest to deal with Pointer Authentication - The usual bunch of cleanups and doc update s390: - fix sigp sense/start/stop/inconsistency - cleanups x86: - Clean up some function prototypes more - improved gfn_to_pfn_cache with proper invalidation, used by Xen emulation - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery - completely remove potential TOC/TOU races in nested SVM consistency checks - update some PMCs on emulated instructions - Intel AMX support (joint work between Thomas and Intel) - large MMU cleanups - module parameter to disable PMU virtualization - cleanup register cache - first part of halt handling cleanups - Hyper-V enlightened MSR bitmap support for nested hypervisors Generic: - clean up Makefiles - introduce CONFIG_HAVE_KVM_DIRTY_RING - optimize memslot lookup using a tree - optimize vCPU array usage by converting to xarray" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (268 commits) x86/fpu: Fix inline prefix warnings selftest: kvm: Add amx selftest selftest: kvm: Move struct kvm_x86_state to header selftest: kvm: Reorder vcpu_load_state steps for AMX kvm: x86: Disable interception for IA32_XFD on demand x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() kvm: selftests: Add support for KVM_CAP_XSAVE2 kvm: x86: Add support for getting/setting expanded xstate buffer x86/fpu: Add uabi_size to guest_fpu kvm: x86: Add CPUID support for Intel AMX kvm: x86: Add XCR0 support for Intel AMX kvm: x86: Disable RDMSR interception of IA32_XFD_ERR kvm: x86: Emulate IA32_XFD_ERR for guest kvm: x86: Intercept #NM for saving IA32_XFD_ERR x86/fpu: Prepare xfd_err in struct fpu_guest kvm: x86: Add emulation for IA32_XFD x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation kvm: x86: Enable dynamic xfeatures at KVM_SET_CPUID2 x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM x86/fpu: Add guest support to xfd_enable_feature() ...
2022-01-07KVM: Reinstate gfn_to_pfn_cache with invalidation supportDavid Woodhouse1-0/+1
This can be used in two modes. There is an atomic mode where the cached mapping is accessed while holding the rwlock, and a mode where the physical address is used by a vCPU in guest mode. For the latter case, an invalidation will wake the vCPU with the new KVM_REQ_GPC_INVALIDATE, and the architecture will need to refresh any caches it still needs to access before entering guest mode again. Only one vCPU can be targeted by the wake requests; it's simple enough to make it wake all vCPUs or even a mask but I don't see a use case for that additional complexity right now. Invalidation happens from the invalidate_range_start MMU notifier, which needs to be able to sleep in order to wake the vCPU and wait for it. This means that revalidation potentially needs to "wait" for the MMU operation to complete and the invalidate_range_end notifier to be invoked. Like the vCPU when it takes a page fault in that period, we just spin — fixing that in a future patch by implementing an actual *wait* may be another part of shaving this particularly hirsute yak. As noted in the comments in the function itself, the only case where the invalidate_range_start notifier is expected to be called *without* being able to sleep is when the OOM reaper is killing the process. In that case, we expect the vCPU threads already to have exited, and thus there will be nothing to wake, and no reason to wait. So we clear the KVM_REQUEST_WAIT bit and send the request anyway, then complain loudly if there actually *was* anything to wake up. Signed-off-by: David Woodhouse <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-12-09KVM: Introduce CONFIG_HAVE_KVM_DIRTY_RINGDavid Woodhouse1-0/+1
I'd like to make the build include dirty_ring.c based on whether the arch wants it or not. That's a whole lot simpler if there's a config symbol instead of doing it implicitly on KVM_DIRTY_LOG_PAGE_OFFSET being set to something non-zero. Signed-off-by: David Woodhouse <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-12-08KVM: Use interval tree to do fast hva lookup in memslotsMaciej S. Szmigiero1-0/+1
The current memslots implementation only allows quick binary search by gfn, quick lookup by hva is not possible - the implementation has to do a linear scan of the whole memslots array, even though the operation being performed might apply just to a single memslot. This significantly hurts performance of per-hva operations with higher memslot counts. Since hva ranges can overlap between memslots an interval tree is needed for tracking them. [sean: handle interval tree updates in kvm_replace_memslot()] Signed-off-by: Maciej S. Szmigiero <[email protected]> Message-Id: <d66b9974becaa9839be9c4e1a5de97b177b4ac20.1638817640.git.maciej.szmigiero@oracle.com>
2021-11-17perf: Force architectures to opt-in to guest callbacksSean Christopherson1-0/+1
Introduce GUEST_PERF_EVENTS and require architectures to select it to allow registering and using guest callbacks in perf. This will hopefully make it more difficult for new architectures to add useless "support" for guest callbacks, e.g. via copy+paste. Stubbing out the helpers has the happy bonus of avoiding a load of perf_guest_cbs when GUEST_PERF_EVENTS=n on arm64/x86. Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2021-10-01KVM: x86: add config for non-kvm users of page trackingDavid Stevens1-0/+3
Add a config option that allows kvm to determine whether or not there are any external users of page tracking. Signed-off-by: David Stevens <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-06-28Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+1
Pull kvm updates from Paolo Bonzini: "This covers all architectures (except MIPS) so I don't expect any other feature pull requests this merge window. ARM: - Add MTE support in guests, complete with tag save/restore interface - Reduce the impact of CMOs by moving them in the page-table code - Allow device block mappings at stage-2 - Reduce the footprint of the vmemmap in protected mode - Support the vGIC on dumb systems such as the Apple M1 - Add selftest infrastructure to support multiple configuration and apply that to PMU/non-PMU setups - Add selftests for the debug architecture - The usual crop of PMU fixes PPC: - Support for the H_RPT_INVALIDATE hypercall - Conversion of Book3S entry/exit to C - Bug fixes S390: - new HW facilities for guests - make inline assembly more robust with KASAN and co x86: - Allow userspace to handle emulation errors (unknown instructions) - Lazy allocation of the rmap (host physical -> guest physical address) - Support for virtualizing TSC scaling on VMX machines - Optimizations to avoid shattering huge pages at the beginning of live migration - Support for initializing the PDPTRs without loading them from memory - Many TLB flushing cleanups - Refuse to load if two-stage paging is available but NX is not (this has been a requirement in practice for over a year) - A large series that separates the MMU mode (WP/SMAP/SMEP etc.) from CR0/CR4/EFER, using the MMU mode everywhere once it is computed from the CPU registers - Use PM notifier to notify the guest about host suspend or hibernate - Support for passing arguments to Hyper-V hypercalls using XMM registers - Support for Hyper-V TLB flush hypercalls and enlightened MSR bitmap on AMD processors - Hide Hyper-V hypercalls that are not included in the guest CPUID - Fixes for live migration of virtual machines that use the Hyper-V "enlightened VMCS" optimization of nested virtualization - Bugfixes (not many) Generic: - Support for retrieving statistics without debugfs - Cleanups for the KVM selftests API" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (314 commits) KVM: x86: rename apic_access_page_done to apic_access_memslot_enabled kvm: x86: disable the narrow guest module parameter on unload selftests: kvm: Allows userspace to handle emulation errors. kvm: x86: Allow userspace to handle emulation errors KVM: x86/mmu: Let guest use GBPAGES if supported in hardware and TDP is on KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Get CR0.WP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT KVM: x86/mmu: Optimize and clean up so called "last nonleaf level" logic KVM: x86: Enhance comments for MMU roles and nested transition trickiness KVM: x86/mmu: WARN on any reserved SPTE value when making a valid SPTE KVM: x86/mmu: Add helpers to do full reserved SPTE checks w/ generic MMU KVM: x86/mmu: Use MMU's role to determine PTTYPE KVM: x86/mmu: Collapse 32-bit PAE and 64-bit statements for helpers KVM: x86/mmu: Add a helper to calculate root from role_regs KVM: x86/mmu: Add helper to update paging metadata KVM: x86/mmu: Don't update nested guest's paging bitmasks if CR0.PG=0 KVM: x86/mmu: Consolidate reset_rsvds_bits_mask() calls KVM: x86/mmu: Use MMU role_regs to get LA57, and drop vCPU LA57 helper KVM: x86/mmu: Get nested MMU's root level from the MMU's role ...
2021-06-17kvm: x86: implement KVM PM-notifierSergey Senozhatsky1-0/+1
Implement PM hibernation/suspend prepare notifiers so that KVM can reliably set PVCLOCK_GUEST_STOPPED on VCPUs and properly suspend VMs. Signed-off-by: Sergey Senozhatsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-05-12kvm: Select SCHED_INFO instead of TASK_DELAY_ACCTPeter Zijlstra1-4/+1
AFAICT KVM only relies on SCHED_INFO. Nothing uses the p->delays data that belongs to TASK_DELAY_ACCT. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Reviewed-by: Ingo Molnar <[email protected]> Acked-by: Paolo Bonzini <[email protected]> Acked-by: Marc Zyngier <[email protected]> Acked-by: Balbir Singh <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2021-04-06x86/sgx: Introduce virtual EPC for use by KVM guestsSean Christopherson1-0/+12
Add a misc device /dev/sgx_vepc to allow userspace to allocate "raw" Enclave Page Cache (EPC) without an associated enclave. The intended and only known use case for raw EPC allocation is to expose EPC to a KVM guest, hence the 'vepc' moniker, virt.{c,h} files and X86_SGX_KVM Kconfig. The SGX driver uses the misc device /dev/sgx_enclave to support userspace in creating an enclave. Each file descriptor returned from opening /dev/sgx_enclave represents an enclave. Unlike the SGX driver, KVM doesn't control how the guest uses the EPC, therefore EPC allocated to a KVM guest is not associated with an enclave, and /dev/sgx_enclave is not suitable for allocating EPC for a KVM guest. Having separate device nodes for the SGX driver and KVM virtual EPC also allows separate permission control for running host SGX enclaves and KVM SGX guests. To use /dev/sgx_vepc to allocate a virtual EPC instance with particular size, the hypervisor opens /dev/sgx_vepc, and uses mmap() with the intended size to get an address range of virtual EPC. Then it may use the address range to create one KVM memory slot as virtual EPC for a guest. Implement the "raw" EPC allocation in the x86 core-SGX subsystem via /dev/sgx_vepc rather than in KVM. Doing so has two major advantages: - Does not require changes to KVM's uAPI, e.g. EPC gets handled as just another memory backend for guests. - EPC management is wholly contained in the SGX subsystem, e.g. SGX does not have to export any symbols, changes to reclaim flows don't need to be routed through KVM, SGX's dirty laundry doesn't have to get aired out for the world to see, and so on and so forth. The virtual EPC pages allocated to guests are currently not reclaimable. Reclaiming an EPC page used by enclave requires a special reclaim mechanism separate from normal page reclaim, and that mechanism is not supported for virutal EPC pages. Due to the complications of handling reclaim conflicts between guest and host, reclaiming virtual EPC pages is significantly more complex than basic support for SGX virtualization. [ bp: - Massage commit message and comments - use cpu_feature_enabled() - vertically align struct members init - massage Virtual EPC clarification text - move Kconfig prompt to Virtualization ] Signed-off-by: Sean Christopherson <[email protected]> Co-developed-by: Kai Huang <[email protected]> Signed-off-by: Kai Huang <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Acked-by: Dave Hansen <[email protected]> Acked-by: Jarkko Sakkinen <[email protected]> Link: https://lkml.kernel.org/r/0c38ced8c8e5a69872db4d6a1c0dabd01e07cad7.1616136308.git.kai.huang@intel.com