[PATCH v2 04/25] KVM: x86: Mark CR4.FRED as not reserved

From: Xin Li
Date: Wed Feb 07 2024 - 13:00:44 EST


The CR4.FRED bit, i.e., CR4[32], is no longer a reserved bit when a guest
enumerates FRED, otherwise it is still a reserved bit.

Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/x86.h | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b5b2d0fde579..0d88873eba63 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -134,7 +134,7 @@
| X86_CR4_OSXSAVE | X86_CR4_SMEP | X86_CR4_FSGSBASE \
| X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_VMXE \
| X86_CR4_SMAP | X86_CR4_PKE | X86_CR4_UMIP \
- | X86_CR4_LAM_SUP))
+ | X86_CR4_LAM_SUP | X86_CR4_FRED))

#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 2f7e19166658..9a52016ebf5a 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -532,6 +532,8 @@ bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type);
__reserved_bits |= X86_CR4_PCIDE; \
if (!__cpu_has(__c, X86_FEATURE_LAM)) \
__reserved_bits |= X86_CR4_LAM_SUP; \
+ if (!__cpu_has(__c, X86_FEATURE_FRED)) \
+ __reserved_bits |= X86_CR4_FRED; \
__reserved_bits; \
})

--
2.43.0