KVM: MMU: fix hashing for TDP and non-paging modes

For TDP mode, avoid creating multiple page table roots for the single
guest-to-host physical address map by fixing the inputs used for the
shadow page table hash in mmu_alloc_roots().

Signed-off-by: Eric Northup <digitaleric@google.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ddfa865..9696d65 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2059,10 +2059,12 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
                hpa_t root = vcpu->arch.mmu.root_hpa;
 
                ASSERT(!VALID_PAGE(root));
-               if (tdp_enabled)
-                       direct = 1;
                if (mmu_check_root(vcpu, root_gfn))
                        return 1;
+               if (tdp_enabled) {
+                       direct = 1;
+                       root_gfn = 0;
+               }
                sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
                                      PT64_ROOT_LEVEL, direct,
                                      ACC_ALL, NULL);
@@ -2072,8 +2074,6 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
                return 0;
        }
        direct = !is_paging(vcpu);
-       if (tdp_enabled)
-               direct = 1;
        for (i = 0; i < 4; ++i) {
                hpa_t root = vcpu->arch.mmu.pae_root[i];
 
@@ -2089,6 +2089,10 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
                        root_gfn = 0;
                if (mmu_check_root(vcpu, root_gfn))
                        return 1;
+               if (tdp_enabled) {
+                       direct = 1;
+                       root_gfn = i << 30;
+               }
                sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
                                      PT32_ROOT_LEVEL, direct,
                                      ACC_ALL, NULL);