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| author | Sheng Yang <sheng@linux.intel.com> | 2010-05-12 16:40:42 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-08-01 10:35:45 +0300 |
| commit | aad827034e419fa8c5ec39e6455266f0b942d856 (patch) | |
| tree | c49cbdc633b0146c9af9fdf5036dfdb09a008d97 | |
| parent | 62ad07551a2ace89e35604d1c55fdae1dd3359a8 (diff) | |
| download | lwn-aad827034e419fa8c5ec39e6455266f0b942d856.tar.gz lwn-aad827034e419fa8c5ec39e6455266f0b942d856.zip | |
KVM: VMX: Only reset MMU when necessary
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>
| -rw-r--r-- | arch/x86/kvm/x86.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 03039fd86980..78147f0421a0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -416,6 +416,10 @@ out: 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; #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_mmu_reset_context(vcpu); + if ((cr0 ^ old_cr0) & update_bits) + kvm_mmu_reset_context(vcpu); 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_mmu_reset_context(vcpu); + if ((cr4 ^ old_cr4) & pdptr_bits) + kvm_mmu_reset_context(vcpu); return 0; } @@ -693,6 +699,8 @@ static u32 emulated_msrs[] = { static int set_efer(struct kvm_vcpu *vcpu, u64 efer) { + u64 old_efer = vcpu->arch.efer; + if (efer & efer_reserved_bits) 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; kvm_mmu_reset_context(vcpu); + /* Update reserved bits */ + if ((efer ^ old_efer) & EFER_NX) + kvm_mmu_reset_context(vcpu); + return 0; } |