[PATCH 4/5] KVM: MMU: Use correct root gfn for direct maps

[Avi Kivity <avi@redhat.com>]

We currently use cr3, which is a random number for direct maps.  Use zero
instead (the start of the linear range mapped by the root).

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/mmu.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4da4ff1..6e925b3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2070,16 +2070,17 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
 	for (i = 0; i < nr_roots; ++i) {
 		root = rootp[i];
 		ASSERT(!VALID_PAGE(root));
-		if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
+
+		if (direct)
+			root_gfn = 0;
+		else if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
 			pdptr = kvm_pdptr_read(vcpu, i);
 			if (!is_present_gpte(pdptr)) {
 				rootp[i] = 0;
 				continue;
 			}
 			root_gfn = pdptr >> PAGE_SHIFT;
-		} else if (vcpu->arch.mmu.root_level == 0)
-			root_gfn = 0;
-		else
+		} else
 			root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
 
 		if (mmu_check_root(vcpu, root_gfn))
-- 
1.7.0.4