KVM: x86: Supplement __cr4_reserved_bits() with X86_FEATURE_PCID check

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>
Message-Id: <20210201142843.108190-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index c5ee0f5ce0f13e236c43cbd4886ef39f3a67c855..0f727b50bd3d2dcabbcf3d661b9b6aefe02e924a 100644 (file)
--- 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;                                \
 })