KVM: X86: Don't unload MMU in kvm_vcpu_flush_tlb_guest()
kvm_mmu_unload() destroys all the PGD caches. Use the lighter
kvm_mmu_sync_roots() and kvm_mmu_sync_prev_roots() instead.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-5-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9d25ef7..3a74540 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3245,15 +3245,14 @@ static void kvm_vcpu_flush_tlb_guest(struct kvm_vcpu *vcpu)
++vcpu->stat.tlb_flush;
if (!tdp_enabled) {
- /*
+ /*
* A TLB flush on behalf of the guest is equivalent to
* INVPCID(all), toggling CR4.PGE, etc., which requires
- * a forced sync of the shadow page tables. Unload the
- * entire MMU here and the subsequent load will sync the
- * shadow page tables, and also flush the TLB.
+ * a forced sync of the shadow page tables. Ensure all the
+ * roots are synced and the guest TLB in hardware is clean.
*/
- kvm_mmu_unload(vcpu);
- return;
+ kvm_mmu_sync_roots(vcpu);
+ kvm_mmu_sync_prev_roots(vcpu);
}
static_call(kvm_x86_tlb_flush_guest)(vcpu);
