| Message ID | 20241003234337.273364-1-seanjc@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: selftests: AVX support + fixes | expand |
On 10/4/24 01:43, Sean Christopherson wrote: > Enable CR4.OSXSAVE and XCR0.AVX by default when creating selftests vCPUs > in order to play nice with compilers that have been configured to enable > -march=x86-64-v3 by default. > > While it would be easier to force v2 (or earlier), there are enough tests > that want XCR0 configured that it will (hopefully) be a net postive to > enable all XCR0 features by default. > > The only real hiccup is the CR4/CPUID sync test, which disables CR4.OSXSAVE > to verify KVM toggles the associated CPUID bit. And if it calls memset() > while OSXAVE is disabled, kablooie. Fixing that requires a bit of assembly, > but overall I think it's worth carrying a few lines of assembly in order to > gain test coverage for running AVX instructions in guests, and boy are > compilers good at abusing AVX :-) > > Fix a few bugs/warts found along the way. Notably, the CPUID test has an > array out-of-bounds bug that can result in false passes (I only noticed > because it was getting a false pass on gcc). I think this is not -rc/stable material, so for now I'm applying Vitaly's patch, plus patch 1 from this series. Paolo > Sean Christopherson (11): > KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups > KVM: selftests: Precisely mask off dynamic fields in CPUID test > KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID > entries > KVM: selftests: Rework OSXSAVE CR4=>CPUID test to play nice with AVX > insns > KVM: selftests: Configure XCR0 to max supported value by default > KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" > KVM: selftests: Drop manual CR4.OSXSAVE enabling from CR4/CPUID sync > test > KVM: selftests: Drop manual XCR0 configuration from AMX test > KVM: selftests: Drop manual XCR0 configuration from state test > KVM: selftests: Drop manual XCR0 configuration from SEV smoke test > KVM: selftests: Ensure KVM supports AVX for SEV-ES VMSA FPU test > > .../selftests/kvm/include/x86_64/processor.h | 5 ++ > .../selftests/kvm/lib/x86_64/processor.c | 24 +++++++ > tools/testing/selftests/kvm/x86_64/amx_test.c | 23 ++----- > .../testing/selftests/kvm/x86_64/cpuid_test.c | 67 ++++++++++++------- > .../kvm/x86_64/cr4_cpuid_sync_test.c | 53 +++++++++------ > .../selftests/kvm/x86_64/sev_smoke_test.c | 19 ++---- > .../testing/selftests/kvm/x86_64/state_test.c | 5 -- > .../selftests/kvm/x86_64/xcr0_cpuid_test.c | 11 ++- > 8 files changed, 122 insertions(+), 85 deletions(-) > > > base-commit: efbc6bd090f48ccf64f7a8dd5daea775821d57ec
On Thu, 03 Oct 2024 16:43:26 -0700, Sean Christopherson wrote: > Enable CR4.OSXSAVE and XCR0.AVX by default when creating selftests vCPUs > in order to play nice with compilers that have been configured to enable > -march=x86-64-v3 by default. > > While it would be easier to force v2 (or earlier), there are enough tests > that want XCR0 configured that it will (hopefully) be a net postive to > enable all XCR0 features by default. > > [...] Applied to kvm-x86 selftests, minus patch 1 which went into 6.12. At some point in the 6.13 cycle I'll send a revert for the "march" madness. [01/11] KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups (no commit info) [02/11] KVM: selftests: Precisely mask off dynamic fields in CPUID test https://github.com/kvm-x86/linux/commit/c0124e2e74a7 [03/11] KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID entries https://github.com/kvm-x86/linux/commit/01e2827157ef [04/11] KVM: selftests: Rework OSXSAVE CR4=>CPUID test to play nice with AVX insns https://github.com/kvm-x86/linux/commit/cf50f01336d3 [05/11] KVM: selftests: Configure XCR0 to max supported value by default https://github.com/kvm-x86/linux/commit/331b8ddaebc1 [06/11] KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" https://github.com/kvm-x86/linux/commit/d87b459428c0 [07/11] KVM: selftests: Drop manual CR4.OSXSAVE enabling from CR4/CPUID sync test https://github.com/kvm-x86/linux/commit/86502f01b8b9 [08/11] KVM: selftests: Drop manual XCR0 configuration from AMX test https://github.com/kvm-x86/linux/commit/fd7b6d77fa6d [09/11] KVM: selftests: Drop manual XCR0 configuration from state test https://github.com/kvm-x86/linux/commit/818646fea3ea [10/11] KVM: selftests: Drop manual XCR0 configuration from SEV smoke test https://github.com/kvm-x86/linux/commit/ce22d24024ea [11/11] KVM: selftests: Ensure KVM supports AVX for SEV-ES VMSA FPU test https://github.com/kvm-x86/linux/commit/08cc7ab1a6ca -- https://github.com/kvm-x86/linux/tree/next
On Thu, Oct 31, 2024, Sean Christopherson wrote: > On Thu, 03 Oct 2024 16:43:26 -0700, Sean Christopherson wrote: > > Enable CR4.OSXSAVE and XCR0.AVX by default when creating selftests vCPUs > > in order to play nice with compilers that have been configured to enable > > -march=x86-64-v3 by default. > > > > While it would be easier to force v2 (or earlier), there are enough tests > > that want XCR0 configured that it will (hopefully) be a net postive to > > enable all XCR0 features by default. > > > > [...] > > Applied to kvm-x86 selftests, minus patch 1 which went into 6.12. At some point > in the 6.13 cycle I'll send a revert for the "march" madness. > > [01/11] KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups > (no commit info) > [02/11] KVM: selftests: Precisely mask off dynamic fields in CPUID test > https://github.com/kvm-x86/linux/commit/c0124e2e74a7 > [03/11] KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID entries > https://github.com/kvm-x86/linux/commit/01e2827157ef > [04/11] KVM: selftests: Rework OSXSAVE CR4=>CPUID test to play nice with AVX insns > https://github.com/kvm-x86/linux/commit/cf50f01336d3 > [05/11] KVM: selftests: Configure XCR0 to max supported value by default > https://github.com/kvm-x86/linux/commit/331b8ddaebc1 > [06/11] KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" > https://github.com/kvm-x86/linux/commit/d87b459428c0 > [07/11] KVM: selftests: Drop manual CR4.OSXSAVE enabling from CR4/CPUID sync test > https://github.com/kvm-x86/linux/commit/86502f01b8b9 > [08/11] KVM: selftests: Drop manual XCR0 configuration from AMX test > https://github.com/kvm-x86/linux/commit/fd7b6d77fa6d > [09/11] KVM: selftests: Drop manual XCR0 configuration from state test > https://github.com/kvm-x86/linux/commit/818646fea3ea > [10/11] KVM: selftests: Drop manual XCR0 configuration from SEV smoke test > https://github.com/kvm-x86/linux/commit/ce22d24024ea > [11/11] KVM: selftests: Ensure KVM supports AVX for SEV-ES VMSA FPU test > https://github.com/kvm-x86/linux/commit/08cc7ab1a6ca And because I mucked up the mmu_stress_test/vcpu_get_reg() series and had to yank it out, the hashes for this series got changed: [02/11] KVM: selftests: Precisely mask off dynamic fields in CPUID test https://github.com/kvm-x86/linux/commit/f2c5aa31670d [03/11] KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID entries https://github.com/kvm-x86/linux/commit/164cea33bfed [04/11] KVM: selftests: Rework OSXSAVE CR4=>CPUID test to play nice with AVX insns https://github.com/kvm-x86/linux/commit/2b9a126a2986 [05/11] KVM: selftests: Configure XCR0 to max supported value by default https://github.com/kvm-x86/linux/commit/8b14c4d85d03 [06/11] KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" https://github.com/kvm-x86/linux/commit/8ae01bf64caa [07/11] KVM: selftests: Drop manual CR4.OSXSAVE enabling from CR4/CPUID sync test https://github.com/kvm-x86/linux/commit/3678c7f6114f [08/11] KVM: selftests: Drop manual XCR0 configuration from AMX test https://github.com/kvm-x86/linux/commit/d87331890a38 [09/11] KVM: selftests: Drop manual XCR0 configuration from state test https://github.com/kvm-x86/linux/commit/28439090ece6 [10/11] KVM: selftests: Drop manual XCR0 configuration from SEV smoke test https://github.com/kvm-x86/linux/commit/3c4c128d02ed [11/11] KVM: selftests: Ensure KVM supports AVX for SEV-ES VMSA FPU test https://github.com/kvm-x86/linux/commit/89f8869835e4
Enable CR4.OSXSAVE and XCR0.AVX by default when creating selftests vCPUs in order to play nice with compilers that have been configured to enable -march=x86-64-v3 by default. While it would be easier to force v2 (or earlier), there are enough tests that want XCR0 configured that it will (hopefully) be a net postive to enable all XCR0 features by default. The only real hiccup is the CR4/CPUID sync test, which disables CR4.OSXSAVE to verify KVM toggles the associated CPUID bit. And if it calls memset() while OSXAVE is disabled, kablooie. Fixing that requires a bit of assembly, but overall I think it's worth carrying a few lines of assembly in order to gain test coverage for running AVX instructions in guests, and boy are compilers good at abusing AVX :-) Fix a few bugs/warts found along the way. Notably, the CPUID test has an array out-of-bounds bug that can result in false passes (I only noticed because it was getting a false pass on gcc). Sean Christopherson (11): KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups KVM: selftests: Precisely mask off dynamic fields in CPUID test KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID entries KVM: selftests: Rework OSXSAVE CR4=>CPUID test to play nice with AVX insns KVM: selftests: Configure XCR0 to max supported value by default KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" KVM: selftests: Drop manual CR4.OSXSAVE enabling from CR4/CPUID sync test KVM: selftests: Drop manual XCR0 configuration from AMX test KVM: selftests: Drop manual XCR0 configuration from state test KVM: selftests: Drop manual XCR0 configuration from SEV smoke test KVM: selftests: Ensure KVM supports AVX for SEV-ES VMSA FPU test .../selftests/kvm/include/x86_64/processor.h | 5 ++ .../selftests/kvm/lib/x86_64/processor.c | 24 +++++++ tools/testing/selftests/kvm/x86_64/amx_test.c | 23 ++----- .../testing/selftests/kvm/x86_64/cpuid_test.c | 67 ++++++++++++------- .../kvm/x86_64/cr4_cpuid_sync_test.c | 53 +++++++++------ .../selftests/kvm/x86_64/sev_smoke_test.c | 19 ++---- .../testing/selftests/kvm/x86_64/state_test.c | 5 -- .../selftests/kvm/x86_64/xcr0_cpuid_test.c | 11 ++- 8 files changed, 122 insertions(+), 85 deletions(-) base-commit: efbc6bd090f48ccf64f7a8dd5daea775821d57ec