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Commit b9baba86 authored by Huaitong Han's avatar Huaitong Han Committed by Paolo Bonzini
Browse files

KVM, pkeys: expose CPUID/CR4 to guest 



X86_FEATURE_PKU is referred to as "PKU" in the hardware documentation:
CPUID.7.0.ECX[3]:PKU. X86_FEATURE_OSPKE is software support for pkeys,
enumerated with CPUID.7.0.ECX[4]:OSPKE, and it reflects the setting of
CR4.PKE(bit 22).

This patch disables CPUID:PKU without ept, because pkeys is not yet
implemented for shadow paging.

Signed-off-by: default avatarHuaitong Han <huaitong.han@intel.com>
Reviewed-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent be94f6b7

arch/x86/include/asm/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -84,7 +84,8 @@ 
			  | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE     \

			  | 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_VMXE | X86_CR4_SMAP))

			  | X86_CR4_OSXMMEXCPT | X86_CR4_VMXE | X86_CR4_SMAP \

			  | X86_CR4_PKE))



#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)

arch/x86/kvm/cpuid.c

+21 −2
Original line number Diff line number Diff line
@@ -88,6 +88,16 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu) 
			apic->lapic_timer.timer_mode_mask = 1 << 17;

	}



	best = kvm_find_cpuid_entry(vcpu, 7, 0);

	if (best) {

		/* Update OSPKE bit */

		if (boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) {

			best->ecx &= ~F(OSPKE);

			if (kvm_read_cr4_bits(vcpu, X86_CR4_PKE))

				best->ecx |= F(OSPKE);

		}

	}



	best = kvm_find_cpuid_entry(vcpu, 0xD, 0);

	if (!best) {

		vcpu->arch.guest_supported_xcr0 = 0;
@@ -360,6 +370,9 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 
	const u32 kvm_cpuid_D_1_eax_x86_features =

		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;



	/* cpuid 7.0.ecx*/

	const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | 0 /*OSPKE*/;



	/* all calls to cpuid_count() should be made on the same cpu */

	get_cpu();
@@ -437,10 +450,16 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 
			cpuid_mask(&entry->ebx, CPUID_7_0_EBX);

			// TSC_ADJUST is emulated

			entry->ebx |= F(TSC_ADJUST);

		} else

			entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;

			cpuid_mask(&entry->ecx, CPUID_7_ECX);

			/* PKU is not yet implemented for shadow paging. */

			if (!tdp_enabled)

				entry->ecx &= ~F(PKU);

		} else {

			entry->ebx = 0;

		entry->eax = 0;

			entry->ecx = 0;

		}

		entry->eax = 0;

		entry->edx = 0;

		break;

	}

arch/x86/kvm/cpuid.h

+8 −0
Original line number Diff line number Diff line
@@ -80,6 +80,14 @@ static inline bool guest_cpuid_has_fsgsbase(struct kvm_vcpu *vcpu) 
	return best && (best->ebx & bit(X86_FEATURE_FSGSBASE));

}



static inline bool guest_cpuid_has_pku(struct kvm_vcpu *vcpu)

{

	struct kvm_cpuid_entry2 *best;



	best = kvm_find_cpuid_entry(vcpu, 7, 0);

	return best && (best->ecx & bit(X86_FEATURE_PKU));

}



static inline bool guest_cpuid_has_longmode(struct kvm_vcpu *vcpu)

{

	struct kvm_cpuid_entry2 *best;

arch/x86/kvm/x86.c

+6 −3
Original line number Diff line number Diff line
@@ -723,7 +723,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
{

	unsigned long old_cr4 = kvm_read_cr4(vcpu);

	unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |

				   X86_CR4_SMEP | X86_CR4_SMAP;

				   X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE;



	if (cr4 & CR4_RESERVED_BITS)

		return 1;
@@ -740,6 +740,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
	if (!guest_cpuid_has_fsgsbase(vcpu) && (cr4 & X86_CR4_FSGSBASE))

		return 1;



	if (!guest_cpuid_has_pku(vcpu) && (cr4 & X86_CR4_PKE))

		return 1;



	if (is_long_mode(vcpu)) {

		if (!(cr4 & X86_CR4_PAE))

			return 1;
@@ -765,7 +768,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
	    (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))

		kvm_mmu_reset_context(vcpu);



	if ((cr4 ^ old_cr4) & X86_CR4_OSXSAVE)

	if ((cr4 ^ old_cr4) & (X86_CR4_OSXSAVE | X86_CR4_PKE))

		kvm_update_cpuid(vcpu);



	return 0;
@@ -7128,7 +7131,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, 


	mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4;

	kvm_x86_ops->set_cr4(vcpu, sregs->cr4);

	if (sregs->cr4 & X86_CR4_OSXSAVE)

	if (sregs->cr4 & (X86_CR4_OSXSAVE | X86_CR4_PKE))

		kvm_update_cpuid(vcpu);



	idx = srcu_read_lock(&vcpu->kvm->srcu);