[PATCH v2 3/3] KVM: Move mmu reload out of line

[Avi Kivity <avi@redhat.com>]

Currently we check that the mmu root exits before every entry.  Use the
existing KVM_REQ_MMU_RELOAD mechanism instead, by making it really reload
the mmu, and by adding the request to mmu initialization code.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/mmu.c |    4 +++-
 arch/x86/kvm/svm.c |    1 +
 arch/x86/kvm/x86.c |   14 +++++++-------
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72102e0..589fdaa 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3181,7 +3181,8 @@ void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
 static void paging_new_cr3(struct kvm_vcpu *vcpu)
 {
 	pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu));
-	mmu_free_roots(vcpu);
+	kvm_mmu_unload(vcpu);
+	kvm_mmu_load(vcpu);
 }
 
 static unsigned long get_cr3(struct kvm_vcpu *vcpu)
@@ -3470,6 +3471,7 @@ static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 
 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
 {
+	kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
 	if (mmu_is_nested(vcpu))
 		return init_kvm_nested_mmu(vcpu);
 	else if (tdp_enabled)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f75af40..98f13d7 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2523,6 +2523,7 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm)
 
 	if (nested_vmcb->control.nested_ctl) {
 		kvm_mmu_unload(&svm->vcpu);
+		kvm_make_request(KVM_REQ_MMU_RELOAD, &svm->vcpu);
 		svm->nested.nested_cr3 = nested_vmcb->control.nested_cr3;
 		nested_svm_init_mmu_context(&svm->vcpu);
 	}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c0209eb..946933a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5240,8 +5240,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (vcpu->requests) {
 		reqs = xchg(&vcpu->requests, 0UL);
 
-		if (test_bit(KVM_REQ_MMU_RELOAD, &reqs))
+		if (test_bit(KVM_REQ_MMU_RELOAD, &reqs)) {
 			kvm_mmu_unload(vcpu);
+			r = kvm_mmu_reload(vcpu);
+			if (unlikely(r)) {
+				kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
+				goto out;
+			}
+		}
 		if (test_bit(KVM_REQ_MIGRATE_TIMER, &reqs))
 			__kvm_migrate_timers(vcpu);
 		if (test_bit(KVM_REQ_CLOCK_UPDATE, &reqs)) {
@@ -5299,12 +5305,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		}
 	}
 
-	r = kvm_mmu_reload(vcpu);
-	if (unlikely(r)) {
-		kvm_x86_ops->cancel_injection(vcpu);
-		goto out;
-	}
-
 	preempt_disable();
 
 	kvm_x86_ops->prepare_guest_switch(vcpu);
-- 
1.7.10.1