KVM: MMU: Convert direct maps to use the generic shadow walker

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

1 files changed, 55 insertions, 38 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8b95cf748b53..a1ca4ff9c116 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1260,49 +1260,66 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
 {
 }
 
-static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
-                        int largepage, gfn_t gfn, pfn_t pfn)
-{
-        hpa_t table_addr = vcpu->arch.mmu.root_hpa;
-        int pt_write = 0;
-        int level = vcpu->arch.mmu.shadow_root_level;
-
-        for (; ; level--) {
-                u32 index = PT64_INDEX(v, level);
-                u64 *table;
+struct direct_shadow_walk {
+        struct kvm_shadow_walk walker;
+        pfn_t pfn;
+        int write;
+        int largepage;
+        int pt_write;
+};
 
-                ASSERT(VALID_PAGE(table_addr));
-                table = __va(table_addr);
+static int direct_map_entry(struct kvm_shadow_walk *_walk,
+                            struct kvm_vcpu *vcpu,
+                            gva_t addr, u64 *sptep, int level)
+{
+        struct direct_shadow_walk *walk =
+                container_of(_walk, struct direct_shadow_walk, walker);
+        struct kvm_mmu_page *sp;
+        gfn_t pseudo_gfn;
+        gfn_t gfn = addr >> PAGE_SHIFT;
+
+        if (level == PT_PAGE_TABLE_LEVEL
+            || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
+                mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
+                             0, walk->write, 1, &walk->pt_write,
+                             walk->largepage, gfn, walk->pfn, false);
+                return 1;
+        }
 
-                if (level == 1 || (largepage && level == 2)) {
-                        mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
-                                     0, write, 1, &pt_write, largepage,
-                                     gfn, pfn, false);
-                        return pt_write;
+        if (*sptep == shadow_trap_nonpresent_pte) {
+                pseudo_gfn = (addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
+                sp = kvm_mmu_get_page(vcpu, pseudo_gfn, addr, level - 1,
+                                      1, ACC_ALL, sptep);
+                if (!sp) {
+                        pgprintk("nonpaging_map: ENOMEM\n");
+                        kvm_release_pfn_clean(walk->pfn);
+                        return -ENOMEM;
                 }
 
-                if (table[index] == shadow_trap_nonpresent_pte) {
-                        struct kvm_mmu_page *new_table;
-                        gfn_t pseudo_gfn;
-
-                        pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
-                                >> PAGE_SHIFT;
-                        new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
-                                                     v, level - 1,
-                                                     1, ACC_ALL, &table[index]);
-                        if (!new_table) {
-                                pgprintk("nonpaging_map: ENOMEM\n");
-                                kvm_release_pfn_clean(pfn);
-                                return -ENOMEM;
-                        }
-
-                        set_shadow_pte(&table[index],
-                                       __pa(new_table->spt)
-                                       | PT_PRESENT_MASK | PT_WRITABLE_MASK
-                                       | shadow_user_mask | shadow_x_mask);
-                }
-                table_addr = table[index] & PT64_BASE_ADDR_MASK;
+                set_shadow_pte(sptep,
+                               __pa(sp->spt)
+                               | PT_PRESENT_MASK | PT_WRITABLE_MASK
+                               | shadow_user_mask | shadow_x_mask);
         }
+        return 0;
+}
+
+static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
+                        int largepage, gfn_t gfn, pfn_t pfn)
+{
+        int r;
+        struct direct_shadow_walk walker = {
+                .walker = { .entry = direct_map_entry, },
+                .pfn = pfn,
+                .largepage = largepage,
+                .write = write,
+                .pt_write = 0,
+        };
+
+        r = walk_shadow(&walker.walker, vcpu, (gva_t)gfn << PAGE_SHIFT);
+        if (r < 0)
+                return r;
+        return walker.pt_write;
 }
 
 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)