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2021-03-15KVM: nSVM: Trace VM-Enter consistency check failuresSean Christopherson1-14/+19
Use trace_kvm_nested_vmenter_failed() and its macro magic to trace consistency check failures on nested VMRUN. Tracing such failures by running the buggy VMM as a KVM guest is often the only way to get a precise explanation of why VMRUN failed. Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: Add missing checks for reserved bits to svm_set_nested_state()Krish Sadhukhan1-15/+39
The path for SVM_SET_NESTED_STATE needs to have the same checks for the CPU registers, as we have in the VMRUN path for a nested guest. This patch adds those missing checks to svm_set_nested_state(). Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: Krish Sadhukhan <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: only copy L1 non-VMLOAD/VMSAVE data in svm_set_nested_state()Paolo Bonzini1-2/+18
The VMLOAD/VMSAVE data is not taken from userspace, since it will not be restored on VMEXIT (it will be copied from VMCB02 to VMCB01). For clarity, replace the wholesale copy of the VMCB save area with a copy of that state only. Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: do not mark all VMCB02 fields dirty on nested vmexitPaolo Bonzini1-6/+12
Since L1 and L2 now use different VMCBs, most of the fields remain the same in VMCB02 from one L2 run to the next. Since KVM itself is not looking at VMCB12's clean field, for now not much can be optimized. However, in the future we could avoid more copies if the VMCB12's SEG and DT sections are clean. Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: do not mark all VMCB01 fields dirty on nested vmexitPaolo Bonzini1-4/+5
Since L1 and L2 now use different VMCBs, most of the fields remain the same from one L1 run to the next. svm_set_cr0 and other functions called by nested_svm_vmexit already take care of clearing the corresponding clean bits; only the TSC offset is special. Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: do not copy vmcb01->control blindly to vmcb02->controlPaolo Bonzini1-2/+21
Most fields were going to be overwritten by vmcb12 control fields, or do not matter at all because they are filled by the processor on vmexit. Therefore, we need not copy them from vmcb01 to vmcb02 on vmentry. Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: nSVM: rename functions and variables according to vmcbXY nomenclaturePaolo Bonzini1-14/+14
Now that SVM is using a separate vmcb01 and vmcb02 (and also uses the vmcb12 naming) we can give clearer names to functions that write to and read from those VMCBs. Likewise, variables and parameters can be renamed from nested_vmcb to vmcb12. Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: SVM: Use a separate vmcb for the nested L2 guestCathy Avery1-78/+82
svm->vmcb will now point to a separate vmcb for L1 (not nested) or L2 (nested). The main advantages are removing get_host_vmcb and hsave, in favor of concepts that are shared with VMX. We don't need anymore to stash the L1 registers in hsave while L2 runs, but we need to copy the VMLOAD/VMSAVE registers from VMCB01 to VMCB02 and back. This more or less has the same cost, but code-wise nested_svm_vmloadsave can be reused. This patch omits several optimizations that are possible: - for simplicity there is some wholesale copying of vmcb.control areas which can go away. - we should be able to better use the VMCB01 and VMCB02 clean bits. - another possibility is to always use VMCB01 for VMLOAD and VMSAVE, thus avoiding the copy of VMLOAD/VMSAVE registers from VMCB01 to VMCB02 and back. Tested: kvm-unit-tests kvm self tests Loaded fedora nested guest on fedora Signed-off-by: Cathy Avery <[email protected]> Message-Id: <[email protected]> [Fix conflicts; keep VMCB02 G_PAT up to date whenever guest writes the PAT MSR; do not copy CR4 over from VMCB01 as it is not needed anymore; add a few more comments. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]>
2021-03-15KVM: x86: to track if L1 is running L2 VMDongli Zhang1-0/+2
The new per-cpu stat 'nested_run' is introduced in order to track if L1 VM is running or used to run L2 VM. An example of the usage of 'nested_run' is to help the host administrator to easily track if any L1 VM is used to run L2 VM. Suppose there is issue that may happen with nested virtualization, the administrator will be able to easily narrow down and confirm if the issue is due to nested virtualization via 'nested_run'. For example, whether the fix like commit 88dddc11a8d6 ("KVM: nVMX: do not use dangling shadow VMCS after guest reset") is required. Cc: Joe Jin <[email protected]> Signed-off-by: Dongli Zhang <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-22KVM: nSVM: prepare guest save area while is_guest_mode is truePaolo Bonzini1-1/+1
Right now, enter_svm_guest_mode is calling nested_prepare_vmcb_save and nested_prepare_vmcb_control. This results in is_guest_mode being false until the end of nested_prepare_vmcb_control. This is a problem because nested_prepare_vmcb_save can in turn cause changes to the intercepts and these have to be applied to the "host VMCB" (stored in svm->nested.hsave) and then merged with the VMCB12 intercepts into svm->vmcb. In particular, without this change we forget to set the CR0 read and CR0 write intercepts when running a real mode L2 guest with NPT disabled. The guest is therefore able to see the CR0.PG bit that KVM sets to enable "paged real mode". This patch fixes the svm.flat mode_switch test case with npt=0. There are no other problematic calls in nested_prepare_vmcb_save. Moving is_guest_mode to the end is done since commit 06fc7772690d ("KVM: SVM: Activate nested state only when guest state is complete", 2010-04-25). However, back then KVM didn't grab a different VMCB when updating the intercepts, it had already copied/merged L1's stuff to L0's VMCB, and then updated L0's VMCB regardless of is_nested(). Later recalc_intercepts was introduced in commit 384c63684397 ("KVM: SVM: Add function to recalculate intercept masks", 2011-01-12). This introduced the bug, because recalc_intercepts now throws away the intercept manipulations that svm_set_cr0 had done in the meanwhile to svm->vmcb. [1] https://lore.kernel.org/kvm/[email protected]/ Reviewed-by: Sean Christopherson <[email protected]> Tested-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-18KVM: nSVM: fix running nested guests when npt=0Paolo Bonzini1-0/+20
In case of npt=0 on host, nSVM needs the same .inject_page_fault tweak as VMX has, to make sure that shadow mmu faults are injected as vmexits. It is not clear why this is needed at all, but for now keep the same code as VMX and we'll fix it for both. Based on a patch by Maxim Levitsky <[email protected]>. Fixes: 7c86663b68ba ("KVM: nSVM: inject exceptions via svm_check_nested_events") Cc: [email protected] Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-18KVM: nSVM: move nested vmrun tracepoint to enter_svm_guest_modeMaxim Levitsky1-12/+14
This way trace will capture all the nested mode entries (including entries after migration, and from smm) Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-04KVM: x86: SEV: Treat C-bit as legal GPA bit regardless of vCPU modeSean Christopherson1-1/+1
Rename cr3_lm_rsvd_bits to reserved_gpa_bits, and use it for all GPA legality checks. AMD's APM states: If the C-bit is an address bit, this bit is masked from the guest physical address when it is translated through the nested page tables. Thus, any access that can conceivably be run through NPT should ignore the C-bit when checking for validity. For features that KVM emulates in software, e.g. MTRRs, there is no clear direction in the APM for how the C-bit should be handled. For such cases, follow the SME behavior inasmuch as possible, since SEV is is essentially a VM-specific variant of SME. For SME, the APM states: In this case the upper physical address bits are treated as reserved when the feature is enabled except where otherwise indicated. Collecting the various relavant SME snippets in the APM and cross- referencing the omissions with Linux kernel code, this leaves MTTRs and APIC_BASE as the only flows that KVM emulates that should _not_ ignore the C-bit. Note, this means the reserved bit checks in the page tables are technically broken. This will be remedied in a future patch. Although the page table checks are technically broken, in practice, it's all but guaranteed to be irrelevant. NPT is required for SEV, i.e. shadowing page tables isn't needed in the common case. Theoretically, the checks could be in play for nested NPT, but it's extremely unlikely that anyone is running nested VMs on SEV, as doing so would require L1 to expose sensitive data to L0, e.g. the entire VMCB. And if anyone is running nested VMs, L0 can't read the guest's encrypted memory, i.e. L1 would need to put its NPT in shared memory, in which case the C-bit will never be set. Or, L1 could use shadow paging, but again, if L0 needs to read page tables, e.g. to load PDPTRs, the memory can't be encrypted if L1 has any expectation of L0 doing the right thing. Cc: Tom Lendacky <[email protected]> Cc: Brijesh Singh <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-04KVM: nSVM: Use common GPA helper to check for illegal CR3Sean Christopherson1-1/+1
Replace an open coded check for an invalid CR3 with its equivalent helper. No functional change intended. Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-04KVM: nSVM: Don't strip host's C-bit from guest's CR3 when reading PDPTRsSean Christopherson1-1/+1
Don't clear the SME C-bit when reading a guest PDPTR, as the GPA (CR3) is in the guest domain. Barring a bizarre paravirtual use case, this is likely a benign bug. SME is not emulated by KVM, loading SEV guest PDPTRs is doomed as KVM can't use the correct key to read guest memory, and setting guest MAXPHYADDR higher than the host, i.e. overlapping the C-bit, would cause faults in the guest. Note, for SEV guests, stripping the C-bit is technically aligned with CPU behavior, but for KVM it's the greater of two evils. Because KVM doesn't have access to the guest's encryption key, ignoring the C-bit would at best result in KVM reading garbage. By keeping the C-bit, KVM will fail its read (unless userspace creates a memslot with the C-bit set). The guest will still undoubtedly die, as KVM will use '0' for the PDPTR value, but that's preferable to interpreting encrypted data as a PDPTR. Fixes: d0ec49d4de90 ("kvm/x86/svm: Support Secure Memory Encryption within KVM") Cc: Tom Lendacky <[email protected]> Cc: Brijesh Singh <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-04KVM: X86: Rename DR6_INIT to DR6_ACTIVE_LOWChenyi Qiang1-1/+1
DR6_INIT contains the 1-reserved bits as well as the bit that is cleared to 0 when the condition (e.g. RTM) happens. The value can be used to initialize dr6 and also be the XOR mask between the #DB exit qualification (or payload) and DR6. Concerning that DR6_INIT is used as initial value only once, rename it to DR6_ACTIVE_LOW and apply it in other places, which would make the incoming changes for bus lock debug exception more simple. Signed-off-by: Chenyi Qiang <[email protected]> Message-Id: <[email protected]> [Define DR6_FIXED_1 from DR6_ACTIVE_LOW and DR6_VOLATILE. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]>
2021-02-03KVM: x86: cleanup CR3 reserved bits checksPaolo Bonzini1-10/+3
If not in long mode, the low bits of CR3 are reserved but not enforced to be zero, so remove those checks. If in long mode, however, the MBZ bits extend down to the highest physical address bit of the guest, excluding the encryption bit. Make the checks consistent with the above, and match them between nested_vmcb_checks and KVM_SET_SREGS. Cc: [email protected] Fixes: 761e41693465 ("KVM: nSVM: Check that MBZ bits in CR3 and CR4 are not set on vmrun of nested guests") Fixes: a780a3ea6282 ("KVM: X86: Fix reserved bits check for MOV to CR3") Reviewed-by: Sean Christopherson <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-01-25KVM: x86: allow KVM_REQ_GET_NESTED_STATE_PAGES outside guest mode for VMXPaolo Bonzini1-0/+3
VMX also uses KVM_REQ_GET_NESTED_STATE_PAGES for the Hyper-V eVMCS, which may need to be loaded outside guest mode. Therefore we cannot WARN in that case. However, that part of nested_get_vmcs12_pages is _not_ needed at vmentry time. Split it out of KVM_REQ_GET_NESTED_STATE_PAGES handling, so that both vmentry and migration (and in the latter case, independent of is_guest_mode) do the parts that are needed. Cc: <[email protected]> # 5.10.x: f2c7ef3ba: KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES Cc: <[email protected]> # 5.10.x Signed-off-by: Paolo Bonzini <[email protected]>
2021-01-07KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexitMaxim Levitsky1-0/+3
It is possible to exit the nested guest mode, entered by svm_set_nested_state prior to first vm entry to it (e.g due to pending event) if the nested run was not pending during the migration. In this case we must not switch to the nested msr permission bitmap. Also add a warning to catch similar cases in the future. Fixes: a7d5c7ce41ac1 ("KVM: nSVM: delay MSR permission processing to first nested VM run") Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-01-07KVM: nSVM: mark vmcb as dirty when forcingly leaving the guest modeMaxim Levitsky1-0/+1
We overwrite most of vmcb fields while doing so, so we must mark it as dirty. Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2021-01-07KVM: nSVM: correctly restore nested_run_pending on migrationMaxim Levitsky1-0/+4
The code to store it on the migration exists, but no code was restoring it. One of the side effects of fixing this is that L1->L2 injected events are no longer lost when migration happens with nested run pending. Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-11-27KVM: nSVM: set fixed bits by handPaolo Bonzini1-4/+5
SVM generally ignores fixed-1 bits. Set them manually so that we do not end up by mistake without those bits set in struct kvm_vcpu; it is part of userspace API that KVM always returns value with the bits set. Signed-off-by: Paolo Bonzini <[email protected]>
2020-11-15KVM: x86: Return bool instead of int for CR4 and SREGS validity checksSean Christopherson1-1/+1
Rework the common CR4 and SREGS checks to return a bool instead of an int, i.e. true/false instead of 0/-EINVAL, and add "is" to the name to clarify the polarity of the return value (which is effectively inverted by this change). No functional changed intended. Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-10-21KVM: nSVM: implement on demand allocation of the nested stateMaxim Levitsky1-0/+42
This way we don't waste memory on VMs which don't use nesting virtualization even when the host enabled it for them. Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: nSVM: delay MSR permission processing to first nested VM runPaolo Bonzini1-3/+18
Allow userspace to set up the memory map after KVM_SET_NESTED_STATE; to do so, move the call to nested_svm_vmrun_msrpm inside the KVM_REQ_GET_NESTED_STATE_PAGES handler (which is currently not used by nSVM). This is similar to what VMX does already. Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: nSVM: CR3 MBZ bits are only 63:52Krish Sadhukhan1-1/+1
Commit 761e4169346553c180bbd4a383aedd72f905bc9a created a wrong mask for the CR3 MBZ bits. According to APM vol 2, only the upper 12 bits are MBZ. Fixes: 761e41693465 ("KVM: nSVM: Check that MBZ bits in CR3 and CR4 are not set on vmrun of nested guests", 2020-07-08) Signed-off-by: Krish Sadhukhan <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Add new intercept word in vmcb_control_areaBabu Moger1-1/+2
The new intercept bits have been added in vmcb control area to support few more interceptions. Here are the some of them. - INTERCEPT_INVLPGB, - INTERCEPT_INVLPGB_ILLEGAL, - INTERCEPT_INVPCID, - INTERCEPT_MCOMMIT, - INTERCEPT_TLBSYNC, Add a new intercept word in vmcb_control_area to support these instructions. Also update kvm_nested_vmrun trace function to support the new addition. AMD documentation for these instructions is available at "AMD64 Architecture Programmer’s Manual Volume 2: System Programming, Pub. 24593 Rev. 3.34(or later)" The documentation can be obtained at the links below: Link: https://www.amd.com/system/files/TechDocs/24593.pdf Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985251547.11252.16994139329949066945.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Modify 64 bit intercept field to two 32 bit vectorsBabu Moger1-15/+10
Convert all the intercepts to one array of 32 bit vectors in vmcb_control_area. This makes it easy for future intercept vector additions. Also update trace functions. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985250813.11252.5736581193881040525.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Modify intercept_exceptions to generic interceptsBabu Moger1-6/+4
Modify intercept_exceptions to generic intercepts in vmcb_control_area. Use the generic vmcb_set_intercept, vmcb_clr_intercept and vmcb_is_intercept to set/clear/test the intercept_exceptions bits. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985250037.11252.1361972528657052410.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Change intercept_dr to generic interceptsBabu Moger1-5/+1
Modify intercept_dr to generic intercepts in vmcb_control_area. Use the generic vmcb_set_intercept, vmcb_clr_intercept and vmcb_is_intercept to set/clear/test the intercept_dr bits. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985249255.11252.10000868032136333355.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Change intercept_cr to generic interceptsBabu Moger1-9/+5
Change intercept_cr to generic intercepts in vmcb_control_area. Use the new vmcb_set_intercept, vmcb_clr_intercept and vmcb_is_intercept where applicable. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985248506.11252.9081085950784508671.stgit@bmoger-ubuntu> [Change constant names. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: SVM: Introduce vmcb_(set_intercept/clr_intercept/_is_intercept)Babu Moger1-0/+12
This is in preparation for the future intercept vector additions. Add new functions vmcb_set_intercept, vmcb_clr_intercept and vmcb_is_intercept using kernel APIs __set_bit, __clear_bit and test_bit espectively. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985247876.11252.16039238014239824460.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: nSVM: Remove unused fieldBabu Moger1-2/+0
host_intercept_exceptions is not used anywhere. Clean it up. Signed-off-by: Babu Moger <[email protected]> Reviewed-by: Jim Mattson <[email protected]> Message-Id: <159985252277.11252.8819848322175521354.stgit@bmoger-ubuntu> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: nSVM: rename nested vmcb to vmcb12Maxim Levitsky1-113/+111
This is to be more consistient with VMX, and to support upcoming addition of vmcb02 Hopefully no functional changes. Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-28KVM: nSVM: Avoid freeing uninitialized pointers in svm_set_nested_state()Vitaly Kuznetsov1-5/+3
The save and ctl pointers are passed uninitialized to kfree() when svm_set_nested_state() follows the 'goto out_set_gif' path. While the issue could've been fixed by initializing these on-stack varialbles to NULL, it seems preferable to eliminate 'out_set_gif' label completely as it is not actually a failure path and duplicating a single svm_set_gif() call doesn't look too bad. [ bp: Drop obscure Addresses-Coverity: tag. ] Fixes: 6ccbd29ade0d ("KVM: SVM: nested: Don't allocate VMCB structures on stack") Reported-by: Dan Carpenter <[email protected]> Reported-by: Joerg Roedel <[email protected]> Reported-by: Colin King <[email protected]> Signed-off-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Reviewed-by: Sean Christopherson <[email protected]> Acked-by: Joerg Roedel <[email protected]> Tested-by: Tom Lendacky <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-22Merge branch 'x86-seves-for-paolo' of ↵Paolo Bonzini1-14/+33
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into HEAD
2020-09-12SVM: nSVM: setup nested msr permission bitmap on nested state loadMaxim Levitsky1-0/+3
This code was missing and was forcing the L2 run with L1's msr permission bitmap Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-12SVM: nSVM: correctly restore GIF on vmexit from nesting after migrationMaxim Levitsky1-1/+3
Currently code in svm_set_nested_state copies the current vmcb control area to L1 control area (hsave->control), under assumption that it mostly reflects the defaults that kvm choose, and later qemu overrides these defaults with L2 state using standard KVM interfaces, like KVM_SET_REGS. However nested GIF (which is AMD specific thing) is by default is true, and it is copied to hsave area as such. This alone is not a big deal since on VMexit, GIF is always set to false, regardless of what it was on VM entry. However in nested_svm_vmexit we were first were setting GIF to false, but then we overwrite the control fields with value from the hsave area. (including the nested GIF field itself if GIF virtualization is enabled). Now on normal vm entry this is not a problem, since GIF is usually false prior to normal vm entry, and this is the value that copied to hsave, and then restored, but this is not always the case when the nested state is loaded as explained above. To fix this issue, move svm_set_gif after we restore the L1 control state in nested_svm_vmexit, so that even with wrong GIF in the saved L1 control area, we still clear GIF as the spec says. Signed-off-by: Maxim Levitsky <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-09-07KVM: SVM: nested: Don't allocate VMCB structures on stackJoerg Roedel1-14/+33
Do not allocate a vmcb_control_area and a vmcb_save_area on the stack, as these structures will become larger with future extenstions of SVM and thus the svm_set_nested_state() function will become a too large stack frame. Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-07-30KVM: nSVM: Correctly set the shadow NPT root level in its MMU roleSean Christopherson1-1/+0
Move the initialization of shadow NPT MMU's shadow_root_level into kvm_init_shadow_npt_mmu() and explicitly set the level in the shadow NPT MMU's role to be the TDP level. This ensures the role and MMU levels are synchronized and also initialized before __kvm_mmu_new_pgd(), which consumes the level when attempting a fast PGD switch. Cc: Vitaly Kuznetsov <[email protected]> Fixes: 9fa72119b24db ("kvm: x86: Introduce kvm_mmu_calc_root_page_role()") Fixes: a506fdd223426 ("KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest switch") Signed-off-by: Sean Christopherson <[email protected]> Message-Id: <[email protected]> Reviewed-by: Vitaly Kuznetsov <[email protected]> Tested-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: remove nonsensical EXITINFO1 adjustment on nested NPFPaolo Bonzini1-7/+0
The "if" that drops the present bit from the page structure fauls makes no sense. It was added by yours truly in order to be bug-compatible with pre-existing code and in order to make the tests pass; however, the tests are wrong. The behavior after this patch matches bare metal. Reported-by: Nadav Amit <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: use nested_svm_load_cr3() on guest->host switchVitaly Kuznetsov1-10/+7
Make nSVM code resemble nVMX where nested_vmx_load_cr3() is used on both guest->host and host->guest transitions. Also, we can now eliminate unconditional kvm_mmu_reset_context() and speed things up. Note, nVMX has two different paths: load_vmcs12_host_state() and nested_vmx_restore_host_state() and the later is used to restore from 'partial' switch to L2, it always uses kvm_mmu_reset_context(). nSVM doesn't have this yet. Also, nested_svm_vmexit()'s return value is almost always ignored nowadays. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: implement nested_svm_load_cr3() and use it for host->guest switchVitaly Kuznetsov1-9/+29
Undesired triple fault gets injected to L1 guest on SVM when L2 is launched with certain CR3 values. #TF is raised by mmu_check_root() check in fast_pgd_switch() and the root cause is that when kvm_set_cr3() is called from nested_prepare_vmcb_save() with NPT enabled CR3 points to a nGPA so we can't check it with kvm_is_visible_gfn(). Using generic kvm_set_cr3() when switching to nested guest is not a great idea as we'll have to distinguish between 'real' CR3s and 'nested' CR3s to e.g. not call kvm_mmu_new_pgd() with nGPA. Following nVMX implement nested-specific nested_svm_load_cr3() doing the job. To support the change, nested_svm_load_cr3() needs to be re-ordered with nested_svm_init_mmu_context(). Note: the current implementation is sub-optimal as we always do TLB flush/MMU sync but this is still an improvement as we at least stop doing kvm_mmu_reset_context(). Fixes: 7c390d350f8b ("kvm: x86: Add fast CR3 switch code path") Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: move kvm_set_cr3() after nested_svm_uninit_mmu_context()Vitaly Kuznetsov1-6/+8
kvm_mmu_new_pgd() refers to arch.mmu and at this point it still references arch.guest_mmu while arch.root_mmu is expected. Note, the change is effectively a nop: when !npt_enabled, nested_svm_uninit_mmu_context() does nothing (as we don't do nested_svm_init_mmu_context()) and with npt_enabled we don't do kvm_set_cr3(). However, it will matter when we move the call to kvm_mmu_new_pgd into nested_svm_load_cr3(). No functional change intended. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: introduce nested_svm_load_cr3()/nested_npt_enabled()Vitaly Kuznetsov1-2/+19
As a preparatory change for implementing nSVM-specific PGD switch (following nVMX' nested_vmx_load_cr3()), introduce nested_svm_load_cr3() instead of relying on kvm_set_cr3(). No functional change intended. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: prepare to handle errors from enter_svm_guest_mode()Vitaly Kuznetsov1-10/+16
Some operations in enter_svm_guest_mode() may fail, e.g. currently we suppress kvm_set_cr3() return value. Prepare the code to proparate errors. No functional change intended. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: reset nested_run_pending upon nested_svm_vmrun_msrpm() failureVitaly Kuznetsov1-0/+2
WARN_ON_ONCE(svm->nested.nested_run_pending) in nested_svm_vmexit() will fire if nested_run_pending remains '1' but it doesn't really need to, we are already failing and not going to run nested guest. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-10KVM: nSVM: split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu()Vitaly Kuznetsov1-1/+2
As a preparatory change for moving kvm_mmu_new_pgd() from nested_prepare_vmcb_save() to nested_svm_init_mmu_context() split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu(). This also makes the code look more like nVMX (kvm_init_shadow_ept_mmu()). No functional change intended. Signed-off-by: Vitaly Kuznetsov <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-08KVM: nSVM: Check that MBZ bits in CR3 and CR4 are not set on vmrun of nested ↵Krish Sadhukhan1-2/+24
guests According to section "Canonicalization and Consistency Checks" in APM vol. 2 the following guest state is illegal: "Any MBZ bit of CR3 is set." "Any MBZ bit of CR4 is set." Suggeted-by: Paolo Bonzini <[email protected]> Signed-off-by: Krish Sadhukhan <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
2020-07-08KVM: SVM: Add svm_ prefix to set/clr/is_intercept()Joerg Roedel1-1/+1
Make clear the symbols belong to the SVM code when they are built-in. No functional changes. Signed-off-by: Joerg Roedel <[email protected]> Message-Id: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
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