On 7/20/26 19:19, Chang S. Bae wrote:
> Hi Paolo and Sean,
>
> Here is another iteration for this enabling series.
>
> One topic worth highlighting first is about how to handle userspace
> writes to the APX state through the KVM XSAVE API, following the
> discussion here:
>
> https://lore.kernel.org/CABgObfaocwfLdUBKJYYYEDH8X3n6iEbMsscbaCe_C=8JNnhDBA@mail.gmail.com
>
> So what this revision ended up with is just to keep those copy paths from
> userspace and acknowledge the redundant copy to VCPU cache / guest
> fpstate. Patch3 has more context on that.
>
> Besides that, this revision has several fixes and improvements. Sean
> gave feedbacks. 0-day spotted on an issue. Also, since the preparatory
> patches have been merged into the mainline, finally a review bot could
> provide some feedbacks as well. The major changes are:
>
> 1. VMX Instruction Information Extension
>
> During the time of V4, 0-day reported out an issue with patch7.
> Fixing that also revealed patch4 was missing another function.
>
> With a review bot's feeback, patch7 was also updated to ensure EGPR
> indices for handling debug-register accesses. Also looking at
> associated macros, patch6 was added for further cleanup.
>
> 2. Emulator Register Tracking
>
> The review bot at hand also found a potential shift-out-bounds issue
> in the register tracking. Patch10 was fixed.
>
> 3. APX Feature Exposure
>
> As per Sean's feedback, the APX XCR0 and userspace exposure were
> reworked a bit in patch14-18.
>
> Along with the in-tree KVM x86 selftests, this time I ensured running the
> x86 KVM-unit-test comparing between:
>
> * Baseline - Paolo's `queue` branch
> * This series on non-APX systems, and
> * This series on APX hardware
>
> The full set is also available at:
>
> git://github.com/intel/apx.git apx-kvm_v5
Thanks, will review. Sashiko was a bit drunk when doing its thing, but
please give a read to its comments in case it found something important.
Paolo
>
> Thanks,
> Chang
>
> Relevant Posting
> * V4: https://lore.kernel.org/20260512011502.53072-1-chang.seok.bae@intel.com
> * KVM-unit-test patch: https://lore.kernel.org/20260420212355.507827-1-chang.seok.bae@intel.com
>
> Chang S. Bae (19):
> KVM: x86: Extend VCPU registers for EGPRs
> KVM: VMX: Save guest EGPRs in VCPU cache
> KVM: x86: Support APX state for XSAVE ABI
> KVM: VMX: Refactor VMX instruction information access
> KVM: VMX: Refactor instruction information decoding
> KVM: VMX: Remove unused control-register access defines
> KVM: VMX: Refactor register index retrieval from exit qualification
> KVM: VMX: Support instruction information extension
> KVM: nVMX: Propagate extended instruction information
> KVM: x86: Support EGPR accessing and tracking for emulator
> KVM: x86: Handle EGPR index and REX2-incompatible opcodes
> KVM: x86: Support REX2-prefixed opcode decode
> KVM: x86: Reject EVEX-prefixed instructions
> KVM: x86: Guard valid XCR0.APX settings
> KVM: x86: Add APX in supported XCR0
> KVM: x86: Expose APX foundation feature to userspace
> KVM: x86: Expose APX sub-features to userspace
> KVM: x86: selftests: Add APX state and ABI test
> KVM: x86: selftests: Add APX state handling and XCR0 sanity checks
>
> Sean Christopherson (1):
> KVM: x86: Move KVM_SUPPORTED_{XCR0,XSS} into kvm_x86_vendor_init()
>
> arch/x86/Kconfig.assembler | 5 +
> arch/x86/include/asm/kvm_host.h | 19 ++
> arch/x86/include/asm/kvm_vcpu_regs.h | 50 +++++
> arch/x86/include/asm/vmx.h | 22 +-
> arch/x86/kvm/Kconfig | 4 +
> arch/x86/kvm/cpuid.c | 27 ++-
> arch/x86/kvm/cpuid.h | 2 +
> arch/x86/kvm/emulate.c | 121 +++++++----
> arch/x86/kvm/kvm_emulate.h | 21 +-
> arch/x86/kvm/reverse_cpuid.h | 6 +
> arch/x86/kvm/svm/svm.c | 8 +-
> arch/x86/kvm/vmenter.h | 1 +
> arch/x86/kvm/vmx/nested.c | 75 +++----
> arch/x86/kvm/vmx/nested.h | 2 +-
> arch/x86/kvm/vmx/vmcs12.c | 1 +
> arch/x86/kvm/vmx/vmcs12.h | 3 +-
> arch/x86/kvm/vmx/vmenter.S | 31 ++-
> arch/x86/kvm/vmx/vmx.c | 28 ++-
> arch/x86/kvm/vmx/vmx.h | 77 ++++++-
> arch/x86/kvm/x86.c | 92 +++++++--
> tools/testing/selftests/kvm/Makefile.kvm | 1 +
> .../selftests/kvm/include/x86/processor.h | 120 +++++++++++
> tools/testing/selftests/kvm/x86/apx_test.c | 191 ++++++++++++++++++
> tools/testing/selftests/kvm/x86/state_test.c | 3 +
> .../selftests/kvm/x86/xcr0_cpuid_test.c | 19 ++
> 25 files changed, 801 insertions(+), 128 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/x86/apx_test.c
>
>
> base-commit: a204badd8432f93b7e862e7dac6db0fe3d65f370