[PATCH 19/22] KVM: MMU: Introduce init_kvm_nested_mmu()

[Joerg Roedel <joerg.roedel@amd.com>]

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>
---
 arch/x86/kvm/mmu.c |   55 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8bd40b5..af89e71 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2136,6 +2136,25 @@ static gpa_t translate_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 *error)
 	return gpa;
 }
 
+static gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 *error)
+{
+	gpa_t t_gpa;
+	u32 access;
+	u32 err;
+
+	BUG_ON(!vcpu->arch.mmu.nested);
+
+	/* NPT walks are treated as user writes */
+	access = PFERR_WRITE_MASK | PFERR_USER_MASK;
+	t_gpa  = vcpu->arch.nested_mmu.gva_to_gpa(vcpu, gpa, access, &err);
+	if (t_gpa == UNMAPPED_GVA) {
+		vcpu->arch.fault_address    = gpa;
+		vcpu->arch.fault_error_code = err | PFERR_NESTED_MASK;
+	}
+
+	return t_gpa;
+}
+
 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
 				  u32 access, u32 *error)
 {
@@ -2465,11 +2484,45 @@ 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;
+	struct kvm_mmu *h_context = &vcpu->arch.mmu;
+
+	g_context->get_cr3           = get_cr3;
+	g_context->translate_gpa     = translate_nested_gpa;
+	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;
+		h_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
+	} else if (is_long_mode(vcpu)) {
+		g_context->root_level = PT64_ROOT_LEVEL;
+		h_context->gva_to_gpa = paging64_gva_to_gpa_nested;
+	} else if (is_pae(vcpu)) {
+		g_context->root_level = PT32E_ROOT_LEVEL;
+		h_context->gva_to_gpa = paging64_gva_to_gpa_nested;
+	} else {
+		g_context->root_level = PT32_ROOT_LEVEL;
+		h_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 (vcpu->arch.mmu.nested)
+		return init_kvm_nested_mmu(vcpu);
+	else if (tdp_enabled)
 		return init_kvm_tdp_mmu(vcpu);
 	else
 		return init_kvm_softmmu(vcpu);
-- 
1.7.0.4