diff options
| author | Junaid Shahid <junaids@google.com> | 2018-06-27 14:59:15 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-08-06 17:58:58 +0200 |
| commit | ade61e2824443a208bb3aaafd8b345ce878298cd (patch) | |
| tree | aae386f7ee3a83188f0d7e5b971763970019d490 /arch/x86/kvm/x86.c | |
| parent | eb4b248e152d3ecf189b9d32c04961360dbd938a (diff) | |
| download | linux-ade61e2824443a208bb3aaafd8b345ce878298cd.tar.bz2 | |
kvm: x86: Skip TLB flush on fast CR3 switch when indicated by guest
When PCIDs are enabled, the MSb of the source operand for a MOV-to-CR3
instruction indicates that the TLB doesn't need to be flushed.
This change enables this optimization for MOV-to-CR3s in the guest
that have been intercepted by KVM for shadow paging and are handled
within the fast CR3 switch path.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7748037b17fd..493afbf12e78 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -847,16 +847,21 @@ EXPORT_SYMBOL_GPL(kvm_set_cr4); int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) { + bool skip_tlb_flush = false; #ifdef CONFIG_X86_64 bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE); - if (pcid_enabled) + if (pcid_enabled) { + skip_tlb_flush = cr3 & CR3_PCID_INVD; cr3 &= ~CR3_PCID_INVD; + } #endif if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) { kvm_mmu_sync_roots(vcpu); - kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); + + if (!skip_tlb_flush) + kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); return 0; } @@ -867,7 +872,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; - kvm_mmu_new_cr3(vcpu, cr3); + kvm_mmu_new_cr3(vcpu, cr3, skip_tlb_flush); vcpu->arch.cr3 = cr3; __set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail); |