KVM: Lazy guest cr3 switching

Switch guest paging context may require us to allocate memory, which
might fail.  Instead of wiring up error paths everywhere, make context
switching lazy and actually do the switch before the next guest entry,
where we can return an error if allocation fails.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 6cd6a50a034..ec040e2f8c5 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1483,6 +1483,10 @@ static int svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	int r;
 
 again:
+	r = kvm_mmu_reload(vcpu);
+	if (unlikely(r))
+		return r;
+
 	if (!vcpu->mmio_read_completed)
 		do_interrupt_requests(vcpu, kvm_run);