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| author | Sean Christopherson <seanjc@google.com> | 2022-11-28 22:57:34 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2022-12-01 15:31:45 -0800 |
| commit | cd5f3d210095347e9d40a9a1d464f5ee0bb5d7f2 (patch) | |
| tree | 5a7273eac6ffa3bc87cad03b4f94b68e1ee96d23 /tools/testing/selftests/kvm/lib/x86_64/processor.c | |
| parent | 2ceade1d363c934633a1788d0f98fc2332062b92 (diff) | |
| download | linux-cd5f3d210095347e9d40a9a1d464f5ee0bb5d7f2.tar.bz2 | |
KVM: selftests: Disallow "get supported CPUID" before REQ_XCOMP_GUEST_PERM
Disallow using kvm_get_supported_cpuid() and thus caching KVM's supported
CPUID info before enabling XSAVE-managed features that are off-by-default
and must be enabled by ARCH_REQ_XCOMP_GUEST_PERM. Caching the supported
CPUID before all XSAVE features are enabled can result in false negatives
due to testing features that were cached before they were enabled.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221128225735.3291648-4-seanjc@google.com
Diffstat (limited to 'tools/testing/selftests/kvm/lib/x86_64/processor.c')
| -rw-r--r-- | tools/testing/selftests/kvm/lib/x86_64/processor.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index 23067465c035..1d3829e652e6 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -601,21 +601,24 @@ void vcpu_arch_free(struct kvm_vcpu *vcpu) free(vcpu->cpuid); } +/* Do not use kvm_supported_cpuid directly except for validity checks. */ +static void *kvm_supported_cpuid; + const struct kvm_cpuid2 *kvm_get_supported_cpuid(void) { - static struct kvm_cpuid2 *cpuid; int kvm_fd; - if (cpuid) - return cpuid; + if (kvm_supported_cpuid) + return kvm_supported_cpuid; - cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES); + kvm_supported_cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES); kvm_fd = open_kvm_dev_path_or_exit(); - kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, cpuid); + kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, + (struct kvm_cpuid2 *)kvm_supported_cpuid); close(kvm_fd); - return cpuid; + return kvm_supported_cpuid; } static uint32_t __kvm_cpu_has(const struct kvm_cpuid2 *cpuid, @@ -684,6 +687,9 @@ void __vm_xsave_require_permission(int bit, const char *name) .addr = (unsigned long) &bitmask }; + TEST_ASSERT(!kvm_supported_cpuid, + "kvm_get_supported_cpuid() cannot be used before ARCH_REQ_XCOMP_GUEST_PERM"); + kvm_fd = open_kvm_dev_path_or_exit(); rc = __kvm_ioctl(kvm_fd, KVM_GET_DEVICE_ATTR, &attr); close(kvm_fd); |