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
--
2.23.0.866.gb869b98d4c-goog
