On 22/10/19 01:30, Aaron Lewis wrote:
> Unify AMD's and Intel's approach for supporting XSAVES. To do this
> change Intel's approach from using the MSR-load areas to writing
> the guest/host values to IA32_XSS on a VM-enter/VM-exit. Switching to
> this strategy allows for a common approach between both AMD and Intel.
> Additionally, define svm_xsaves_supported() based on AMD's feedback, and add
> vcpu->arch.xsaves_enabled to track whether XSAVES is enabled in the guest.
>
> This change sets up IA32_XSS to be a non-zero value in the future, which
> may happen sooner than later with support for guest CET feature being
> added.
>
> v2 -> v3:
> - Remove guest_xcr0_loaded from kvm_vcpu.
> - Add vcpu->arch.xsaves_enabled.
> - Add staged rollout to load the hardware IA32_XSS MSR with guest/host
> values on VM-entry and VM-exit:
> 1) Introduce vcpu->arch->xsaves_enabled.
> 2) Add svm implementation for switching between guest and host IA32_XSS.
> 3) Add vmx implementation for switching between guest and host IA32_XSS.
> 4) Remove svm and vmx implementation and add it to common code.
>
> v1 -> v2:
> - Add the flag xsaves_enabled to kvm_vcpu_arch to track when XSAVES is
> enabled in the guest, whether or not XSAVES is enumerated in the
> guest CPUID.
> - Remove code that sets the X86_FEATURE_XSAVES bit in the guest CPUID
> which was added in patch "Enumerate XSAVES in guest CPUID when it is
> available to the guest". As a result we no longer need that patch.
> - Added a comment to kvm_set_msr_common to describe how to save/restore
> PT MSRS without using XSAVES/XRSTORS.
> - Added more comments to the "Add support for XSAVES on AMD" patch.
> - Replaced vcpu_set_msr_expect_result() with _vcpu_set_msr() in the
> test library.
>
> Aaron Lewis (9):
> KVM: x86: Introduce vcpu->arch.xsaves_enabled
> KVM: VMX: Fix conditions for guest IA32_XSS support
> KVM: x86: Remove unneeded kvm_vcpu variable, guest_xcr0_loaded
> KVM: SVM: Use wrmsr for switching between guest and host IA32_XSS on AMD
> KVM: VMX: Use wrmsr for switching between guest and host IA32_XSS on Intel
> KVM: x86: Move IA32_XSS-swapping on VM-entry/VM-exit to common x86 code
> kvm: x86: Move IA32_XSS to kvm_{get,set}_msr_common
> kvm: svm: Update svm_xsaves_supported
> kvm: tests: Add test to verify MSR_IA32_XSS
>
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/svm.c | 9 ++-
> arch/x86/kvm/vmx/vmx.c | 41 ++--------
> arch/x86/kvm/x86.c | 52 ++++++++++---
> arch/x86/kvm/x86.h | 4 +-
> include/linux/kvm_host.h | 1 -
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/include/x86_64/processor.h | 7 +-
> .../selftests/kvm/lib/x86_64/processor.c | 72 +++++++++++++++---
> .../selftests/kvm/x86_64/xss_msr_test.c | 76 +++++++++++++++++++
> 11 files changed, 205 insertions(+), 60 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/x86_64/xss_msr_test.c
>
Queued, thanks.
Paolo
