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KVM: selftests: Check KVM's supported CPUID, not host CPUID, for XFD

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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 <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-39-seanjc@google.com
This commit is contained in:
Sean Christopherson 2022-06-14 20:07:03 +00:00
parent d04019274d
commit 7fbb653e01
2 changed files with 3 additions and 17 deletions
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1
tools/testing/selftests/kvm/include/x86_64/processor.h
View File

@ -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

19
tools/testing/selftests/kvm/lib/x86_64/processor.c
View File

@ -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);
/*