KVM: MMU: Introduce init_kvm_nested_mmu()

This patch introduces the init_kvm_nested_mmu() function
which is used to re-initialize the nested mmu when the l2
guest changes its paging mode.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 36 insertions, 1 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 1e215e8b9377..a26f13bd34e0 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2784,11 +2784,46 @@ static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
         return r;
 }
 
+static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
+{
+        struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
+
+        g_context->get_cr3           = get_cr3;
+        g_context->inject_page_fault = kvm_inject_page_fault;
+
+        /*
+         * Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The
+         * translation of l2_gpa to l1_gpa addresses is done using the
+         * arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
+         * functions between mmu and nested_mmu are swapped.
+         */
+        if (!is_paging(vcpu)) {
+                g_context->root_level = 0;
+                g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
+        } else if (is_long_mode(vcpu)) {
+                reset_rsvds_bits_mask(vcpu, g_context, PT64_ROOT_LEVEL);
+                g_context->root_level = PT64_ROOT_LEVEL;
+                g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
+        } else if (is_pae(vcpu)) {
+                reset_rsvds_bits_mask(vcpu, g_context, PT32E_ROOT_LEVEL);
+                g_context->root_level = PT32E_ROOT_LEVEL;
+                g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
+        } else {
+                reset_rsvds_bits_mask(vcpu, g_context, PT32_ROOT_LEVEL);
+                g_context->root_level = PT32_ROOT_LEVEL;
+                g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
+        }
+
+        return 0;
+}
+
 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
 {
         vcpu->arch.update_pte.pfn = bad_pfn;
 
-        if (tdp_enabled)
+        if (mmu_is_nested(vcpu))
+                return init_kvm_nested_mmu(vcpu);
+        else if (tdp_enabled)
                 return init_kvm_tdp_mmu(vcpu);
         else
                 return init_kvm_softmmu(vcpu);