linux-kernel - [PATCH v1 04/23] KVM: x86: Mark CR4.FRED as not reserved

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Date:   Wed,  8 Nov 2023 10:29:44 -0800
From:   Xin Li <xin3.li@...el.com>
To:     kvm@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org,
        linux-kselftest@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com, corbet@....net,
        kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org,
        decui@...rosoft.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, vkuznets@...hat.com, peterz@...radead.org,
        ravi.v.shankar@...el.com
Subject: [PATCH v1 04/23] KVM: x86: Mark CR4.FRED as not reserved

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.

Tested-by: Shan Kang <shan.kang@...el.com>
Signed-off-by: Xin Li <xin3.li@...el.com>
---
 arch/x86/include/asm/kvm_host.h | 3 ++-
 arch/x86/kvm/x86.h              | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d7036982332e..1e5a6d9439f8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -133,7 +133,8 @@
 			  | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_PCIDE \
 			  | 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_SMAP | X86_CR4_PKE | X86_CR4_UMIP \
+			  | 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 5184fde1dc54..60da8cbe6759 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -530,6 +530,8 @@ bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type);
 		__reserved_bits |= X86_CR4_VMXE;        \
 	if (!__cpu_has(__c, X86_FEATURE_PCID))          \
 		__reserved_bits |= X86_CR4_PCIDE;       \
+	if (!__cpu_has(__c, X86_FEATURE_FRED))          \
+		__reserved_bits |= X86_CR4_FRED;        \
 	__reserved_bits;                                \
 })
 
-- 
2.42.0