On Tue, Dec 27, 2022 at 10:38 AM Aaron Lewis <aaronlewis@xxxxxxxxxx> wrote: > > When running a SPR guest without AMX enabled Can you clarify what "without AMX enabled" means? Do you mean that userspace hasn't opted in to AMX via arch_prctl()? > CPUID.(EAX=0DH,ECX=0):EAX.XTILE_CFG[bit-17] will be set and > CPUID.(EAX=0DH,ECX=0):EAX.XTILE_DATA[bit-18] will be clear. While this > is architecturally correct it can be a little awkward for userspace > or a guest when using them. Instead of leaving the CPUID leaf in a > half baked state, either clear them both or leave them both set. > > Additionally, add testing to verify the CPUID isn't in such a state. > > Aaron Lewis (3): > KVM: x86: Clear XTILE_CFG if XTILE_DATA is clear > KVM: selftests: Hoist XGETBV and XSETBV to make them more accessible > KVM: selftests: Add XCR0 Test > > arch/x86/kvm/cpuid.c | 4 + > tools/testing/selftests/kvm/Makefile | 1 + > .../selftests/kvm/include/x86_64/processor.h | 19 +++ > tools/testing/selftests/kvm/x86_64/amx_test.c | 24 +--- > .../selftests/kvm/x86_64/xcr0_cpuid_test.c | 134 ++++++++++++++++++ > 5 files changed, 161 insertions(+), 21 deletions(-) > create mode 100644 tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c > > -- > 2.39.0.314.g84b9a713c41-goog >
