On 01/02/21 15:28, Vitaly Kuznetsov wrote:
Commit 7a873e455567 ("KVM: selftests: Verify supported CR4 bits can be set
before KVM_SET_CPUID2") reveals that KVM allows to set X86_CR4_PCIDE even
when PCID support is missing:
==== Test Assertion Failure ====
x86_64/set_sregs_test.c:41: rc
pid=6956 tid=6956 - Invalid argument
1 0x000000000040177d: test_cr4_feature_bit at set_sregs_test.c:41
2 0x00000000004014fc: main at set_sregs_test.c:119
3 0x00007f2d9346d041: ?? ??:0
4 0x000000000040164d: _start at ??:?
KVM allowed unsupported CR4 bit (0x20000)
Add X86_FEATURE_PCID feature check to __cr4_reserved_bits() to make
kvm_is_valid_cr4() fail.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
arch/x86/kvm/x86.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index c5ee0f5ce0f1..0f727b50bd3d 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -425,6 +425,8 @@ bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type);
__reserved_bits |= X86_CR4_UMIP; \
if (!__cpu_has(__c, X86_FEATURE_VMX)) \
__reserved_bits |= X86_CR4_VMXE; \
+ if (!__cpu_has(__c, X86_FEATURE_PCID)) \
+ __reserved_bits |= X86_CR4_PCIDE; \
__reserved_bits; \
})
Queued, thanks.
Paolo
