linux-kernel - [PATCH 12/27] KVM: MMU: Implement nested gva_to

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Message-ID: <1283788566-29186-13-git-send-email-joerg.roedel@amd.com>
Date:	Mon, 6 Sep 2010 17:55:51 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>
CC:	Alexander Graf <agraf@...e.de>, <joro@...tes.org>,
	<kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 12/27] KVM: MMU: Implement nested gva_to_gpa functions

This patch adds the functions to do a nested l2_gva to
l1_gpa page table walk.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 arch/x86/include/asm/kvm_host.h |   10 ++++++++++
 arch/x86/kvm/mmu.c              |    8 ++++++++
 arch/x86/kvm/paging_tmpl.h      |   31 +++++++++++++++++++++++++++++++
 arch/x86/kvm/x86.h              |    5 +++++
 4 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d797746..9b9c096 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -298,6 +298,16 @@ struct kvm_vcpu_arch {
 	struct kvm_mmu mmu;
 
 	/*
+	 * Paging state of an L2 guest (used for nested npt)
+	 *
+	 * This context will save all necessary information to walk page tables
+	 * of the an L2 guest. This context is only initialized for page table
+	 * walking and not for faulting since we never handle l2 page faults on
+	 * the host.
+	 */
+	struct kvm_mmu nested_mmu;
+
+	/*
 	 * Pointer to the mmu context currently used for
 	 * gva_to_gpa translations.
 	 */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a2cd2ce..1f425f3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2466,6 +2466,14 @@ static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
 	return vaddr;
 }
 
+static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
+					 u32 access, u32 *error)
+{
+	if (error)
+		*error = 0;
+	return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, error);
+}
+
 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 				u32 error_code)
 {
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index f26fee9..cd59af1 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -272,6 +272,16 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
 					write_fault, user_fault, fetch_fault);
 }
 
+static int FNAME(walk_addr_nested)(struct guest_walker *walker,
+				   struct kvm_vcpu *vcpu, gva_t addr,
+				   int write_fault, int user_fault,
+				   int fetch_fault)
+{
+	return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.nested_mmu,
+					addr, write_fault, user_fault,
+					fetch_fault);
+}
+
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 			      u64 *spte, const void *pte)
 {
@@ -656,6 +666,27 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access,
 	return gpa;
 }
 
+static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gva_t vaddr,
+				      u32 access, u32 *error)
+{
+	struct guest_walker walker;
+	gpa_t gpa = UNMAPPED_GVA;
+	int r;
+
+	r = FNAME(walk_addr_nested)(&walker, vcpu, vaddr,
+				    access & PFERR_WRITE_MASK,
+				    access & PFERR_USER_MASK,
+				    access & PFERR_FETCH_MASK);
+
+	if (r) {
+		gpa = gfn_to_gpa(walker.gfn);
+		gpa |= vaddr & ~PAGE_MASK;
+	} else if (error)
+		*error = walker.error_code;
+
+	return gpa;
+}
+
 static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
 				 struct kvm_mmu_page *sp)
 {
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 2d6385e..bf4dc2f 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -50,6 +50,11 @@ static inline int is_long_mode(struct kvm_vcpu *vcpu)
 #endif
 }
 
+static inline bool mmu_is_nested(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.walk_mmu == &vcpu->arch.nested_mmu;
+}
+
 static inline int is_pae(struct kvm_vcpu *vcpu)
 {
 	return kvm_read_cr4_bits(vcpu, X86_CR4_PAE);
-- 
1.7.0.4


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