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@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1b3eb8a..8ec3547 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -295,6 +295,16 @@ 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 cb06ada..1e215e8 100644 (file)
--- 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, access);
+}
+
 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 a704a81..eefe363 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -276,6 +276,16 @@ 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)
 {
@@ -660,6 +670,27 @@ 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 (file)
--- 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);