| Message ID | 20210201142843.108190-1-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Supplement __cr4_reserved_bits() with X86_FEATURE_PCID check | expand |
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@redhat.com> > --- > 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
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; \ })
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@redhat.com> --- arch/x86/kvm/x86.h | 2 ++ 1 file changed, 2 insertions(+)