From 7fbb653e01fdd45b377674a9e77da473d49afd38 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 14 Jun 2022 20:07:03 +0000 Subject: [PATCH] KVM: selftests: Check KVM's supported CPUID, not host CPUID, for XFD Use kvm_cpu_has() to check for XFD supported in vm_xsave_req_perm(), simply checking host CPUID doesn't guarantee KVM supports AMX/XFD. Opportunistically hoist the check above the bit check; if XFD isn't supported, it's far better to get a "not supported at all" message, as opposed to a "feature X isn't supported" message". Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20220614200707.3315957-39-seanjc@google.com --- .../testing/selftests/kvm/include/x86_64/processor.h | 1 + tools/testing/selftests/kvm/lib/x86_64/processor.c | 19 ++----------------- 2 files changed, 3 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index ecf2ace..559840e 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -117,6 +117,7 @@ struct kvm_x86_cpu_feature { #define X86_FEATURE_XTILECFG KVM_X86_CPU_FEATURE(0xD, 0, EAX, 17) #define X86_FEATURE_XTILEDATA KVM_X86_CPU_FEATURE(0xD, 0, EAX, 18) #define X86_FEATURE_XSAVES KVM_X86_CPU_FEATURE(0xD, 1, EAX, 3) +#define X86_FEATURE_XFD KVM_X86_CPU_FEATURE(0xD, 1, EAX, 4) /* * Extended Leafs, a.k.a. AMD defined diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index e2894b5..6cb93bb 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -578,21 +578,6 @@ static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu) vcpu_sregs_set(vcpu, &sregs); } -#define CPUID_XFD_BIT (1 << 4) -static bool is_xfd_supported(void) -{ - int eax, ebx, ecx, edx; - const int leaf = 0xd, subleaf = 0x1; - - __asm__ __volatile__( - "cpuid" - : /* output */ "=a"(eax), "=b"(ebx), - "=c"(ecx), "=d"(edx) - : /* input */ "0"(leaf), "2"(subleaf)); - - return !!(eax & CPUID_XFD_BIT); -} - void vm_xsave_req_perm(int bit) { int kvm_fd; @@ -604,6 +589,8 @@ void vm_xsave_req_perm(int bit) .addr = (unsigned long) &bitmask }; + TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XFD)); + kvm_fd = open_kvm_dev_path_or_exit(); rc = __kvm_ioctl(kvm_fd, KVM_GET_DEVICE_ATTR, &attr); close(kvm_fd); @@ -614,8 +601,6 @@ void vm_xsave_req_perm(int bit) TEST_REQUIRE(bitmask & (1ULL << bit)); - TEST_REQUIRE(is_xfd_supported()); - rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_GUEST_PERM, bit); /* -- 2.7.4