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KVM: VMX: Only reset MMU when necessary

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Only modifying some bits of CR0/CR4 needs paging mode switch.

Modify EFER.NXE bit would result in reserved bit updates.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Sheng Yang 2010-05-12 16:40:42 +08:00 committed by Avi Kivity
parent 62ad07551a
commit aad827034e
1 changed files with 14 additions and 2 deletions
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16
arch/x86/kvm/x86.c
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@ -416,6 +416,10 @@ out:
static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{ {
unsigned long old_cr0 = kvm_read_cr0(vcpu);
unsigned long update_bits = X86_CR0_PG | X86_CR0_WP |
X86_CR0_CD | X86_CR0_NW;
cr0 |= X86_CR0_ET; cr0 |= X86_CR0_ET;
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
@ -449,7 +453,8 @@ static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
kvm_x86_ops->set_cr0(vcpu, cr0); kvm_x86_ops->set_cr0(vcpu, cr0);
kvm_mmu_reset_context(vcpu); if ((cr0 ^ old_cr0) & update_bits)
kvm_mmu_reset_context(vcpu);
return 0; return 0;
} }
@ -487,7 +492,8 @@ int __kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
kvm_x86_ops->set_cr4(vcpu, cr4); kvm_x86_ops->set_cr4(vcpu, cr4);
kvm_mmu_reset_context(vcpu); if ((cr4 ^ old_cr4) & pdptr_bits)
kvm_mmu_reset_context(vcpu);
return 0; return 0;
} }
@ -693,6 +699,8 @@ static u32 emulated_msrs[] = {
static int set_efer(struct kvm_vcpu *vcpu, u64 efer) static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
{ {
u64 old_efer = vcpu->arch.efer;
if (efer & efer_reserved_bits) if (efer & efer_reserved_bits)
return 1; return 1;
@ -724,6 +732,10 @@ static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
vcpu->arch.mmu.base_role.nxe = (efer & EFER_NX) && !tdp_enabled; vcpu->arch.mmu.base_role.nxe = (efer & EFER_NX) && !tdp_enabled;
kvm_mmu_reset_context(vcpu); kvm_mmu_reset_context(vcpu);
/* Update reserved bits */
if ((efer ^ old_efer) & EFER_NX)
kvm_mmu_reset_context(vcpu);
return 0; return 0;
} }