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>

1 files changed, 8 insertions, 4 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ddfa8658fb6d..9696d654b01f 100644
--- 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);