[v2,0/5] Add support for XSAVES on AMD and unify it with Intel

Message

Aaron Lewis Oct. 11, 2019, 7:40 p.m. UTC

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 IA32_XSS to the emulated_msrs list, in preparation for the day when
the guest IA32_XSS may contain a non-zero value.

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.

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 (5):
  KVM: VMX: Remove unneeded check for X86_FEATURE_XSAVE
  KVM: VMX: Use wrmsr for switching between guest and host IA32_XSS
  kvm: svm: Add support for XSAVES on AMD
  kvm: x86: Add IA32_XSS to the emulated_msrs list
  kvm: tests: Add test to verify MSR_IA32_XSS

 arch/x86/include/asm/kvm_host.h               |  1 +
 arch/x86/kvm/svm.c                            | 19 +++--
 arch/x86/kvm/vmx/vmx.c                        | 46 ++++--------
 arch/x86/kvm/x86.c                            | 46 ++++++++++--
 arch/x86/kvm/x86.h                            |  4 +-
 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       | 70 ++++++++++++++++++
 10 files changed, 210 insertions(+), 57 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/x86_64/xss_msr_test.c