Commit 345599f9 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Add macro to ensure reserved cr4 bits checks stay in sync 



Add a helper macro to generate the set of reserved cr4 bits for both
host and guest to ensure that adding a check on guest capabilities is
also added for host capabilities, and vice versa.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 96be4e06

arch/x86/kvm/x86.c

+25 −40
Original line number Diff line number Diff line
@@ -881,31 +881,34 @@ int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr) 
}

EXPORT_SYMBOL_GPL(kvm_set_xcr);



#define __cr4_reserved_bits(__cpu_has, __c)		\

({							\

	u64 __reserved_bits = CR4_RESERVED_BITS;	\

							\

	if (!__cpu_has(__c, X86_FEATURE_XSAVE))		\

		__reserved_bits |= X86_CR4_OSXSAVE;	\

	if (!__cpu_has(__c, X86_FEATURE_SMEP))		\

		__reserved_bits |= X86_CR4_SMEP;	\

	if (!__cpu_has(__c, X86_FEATURE_SMAP))		\

		__reserved_bits |= X86_CR4_SMAP;	\

	if (!__cpu_has(__c, X86_FEATURE_FSGSBASE))	\

		__reserved_bits |= X86_CR4_FSGSBASE;	\

	if (!__cpu_has(__c, X86_FEATURE_PKU))		\

		__reserved_bits |= X86_CR4_PKE;		\

	if (!__cpu_has(__c, X86_FEATURE_LA57))		\

		__reserved_bits |= X86_CR4_LA57;	\

	__reserved_bits;				\

})



static u64 kvm_host_cr4_reserved_bits(struct cpuinfo_x86 *c)

{

	u64 reserved_bits = CR4_RESERVED_BITS;



	if (!cpu_has(c, X86_FEATURE_XSAVE))

		reserved_bits |= X86_CR4_OSXSAVE;



	if (!cpu_has(c, X86_FEATURE_SMEP))

		reserved_bits |= X86_CR4_SMEP;



	if (!cpu_has(c, X86_FEATURE_SMAP))

		reserved_bits |= X86_CR4_SMAP;



	if (!cpu_has(c, X86_FEATURE_FSGSBASE))

		reserved_bits |= X86_CR4_FSGSBASE;

	u64 reserved_bits = __cr4_reserved_bits(cpu_has, c);



	if (!cpu_has(c, X86_FEATURE_PKU))

		reserved_bits |= X86_CR4_PKE;

	if (cpuid_ecx(0x7) & bit(X86_FEATURE_LA57))

		reserved_bits &= ~X86_CR4_LA57;



	if (!cpu_has(c, X86_FEATURE_LA57) &&

	    !(cpuid_ecx(0x7) & bit(X86_FEATURE_LA57)))

		reserved_bits |= X86_CR4_LA57;



	if (!cpu_has(c, X86_FEATURE_UMIP) && !kvm_x86_ops->umip_emulated())

		reserved_bits |= X86_CR4_UMIP;

	if (kvm_x86_ops->umip_emulated())

		reserved_bits &= ~X86_CR4_UMIP;



	return reserved_bits;

}
@@ -915,25 +918,7 @@ static int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
	if (cr4 & cr4_reserved_bits)

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && (cr4 & X86_CR4_OSXSAVE))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_SMEP) && (cr4 & X86_CR4_SMEP))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_SMAP) && (cr4 & X86_CR4_SMAP))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_FSGSBASE) && (cr4 & X86_CR4_FSGSBASE))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_PKU) && (cr4 & X86_CR4_PKE))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_LA57) && (cr4 & X86_CR4_LA57))

		return -EINVAL;



	if (!guest_cpuid_has(vcpu, X86_FEATURE_UMIP) && (cr4 & X86_CR4_UMIP))

	if (cr4 & __cr4_reserved_bits(guest_cpuid_has, vcpu))

		return -EINVAL;



	return 0;

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