From c30a358d33e0e111f06e54a4a4125371e6b6693c Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Fri, 10 Sep 2010 17:30:48 +0200
Subject: [PATCH] KVM: MMU: Add infrastructure for two-level page walker

This patch introduces a mmu-callback to translate gpa
addresses in the walk_addr code. This is later used to
translate l2_gpa addresses into l1_gpa addresses.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/x86.c              | 6 ++++++
 include/linux/kvm_host.h        | 5 +++++
 3 files changed, 12 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3fde5b322534..4915b7c8f2ec 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -243,6 +243,7 @@ struct kvm_mmu {
 	void (*free)(struct kvm_vcpu *vcpu);
 	gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access,
 			    u32 *error);
+	gpa_t (*translate_gpa)(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access);
 	void (*prefetch_page)(struct kvm_vcpu *vcpu,
 			      struct kvm_mmu_page *page);
 	int (*sync_page)(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 48b74d2fbfb7..2364c2cad891 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3448,6 +3448,11 @@ void kvm_get_segment(struct kvm_vcpu *vcpu,
 	kvm_x86_ops->get_segment(vcpu, var, seg);
 }
 
+static gpa_t translate_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access)
+{
+	return gpa;
+}
+
 gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
 	u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
@@ -5659,6 +5664,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.emulate_ctxt.ops = &emulate_ops;
 	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
+	vcpu->arch.mmu.translate_gpa = translate_gpa;
 	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))
 		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 	else
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f2ecdd52032b..917e68ff5ed2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -534,6 +534,11 @@ static inline gpa_t gfn_to_gpa(gfn_t gfn)
 	return (gpa_t)gfn << PAGE_SHIFT;
 }
 
+static inline gfn_t gpa_to_gfn(gpa_t gpa)
+{
+	return (gfn_t)(gpa >> PAGE_SHIFT);
+}
+
 static inline hpa_t pfn_to_hpa(pfn_t pfn)
 {
 	return (hpa_t)pfn << PAGE_SHIFT;
-- 
2.20.1