KVM: MMU: Replace walk_shadow() by for_each_shadow_entry() in fetch()

Effectively reverting to the pre walk_shadow() version -- but now
with the reusable for_each().

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

1 files changed, 58 insertions, 70 deletions

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 9fd78b6e17ad..69c7e3311b8a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -283,91 +283,79 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
 /*
  * Fetch a shadow pte for a specific level in the paging hierarchy.
  */
-static int FNAME(shadow_walk_entry)(struct kvm_shadow_walk *_sw,
-                                    struct kvm_vcpu *vcpu, u64 addr,
-                                    u64 *sptep, int level)
+static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
+                         struct guest_walker *gw,
+                         int user_fault, int write_fault, int largepage,
+                         int *ptwrite, pfn_t pfn)
 {
-        struct shadow_walker *sw =
-                container_of(_sw, struct shadow_walker, walker);
-        struct guest_walker *gw = sw->guest_walker;
         unsigned access = gw->pt_access;
         struct kvm_mmu_page *shadow_page;
-        u64 spte;
+        u64 spte, *sptep;
         int metaphysical;
         gfn_t table_gfn;
         int r;
+        int level;
         pt_element_t curr_pte;
+        struct kvm_shadow_walk_iterator iterator;
 
-        if (level == PT_PAGE_TABLE_LEVEL
-            || (sw->largepage && level == PT_DIRECTORY_LEVEL)) {
-                mmu_set_spte(vcpu, sptep, access, gw->pte_access & access,
-                             sw->user_fault, sw->write_fault,
-                             gw->ptes[gw->level-1] & PT_DIRTY_MASK,
-                             sw->ptwrite, sw->largepage,
-                             gw->ptes[gw->level-1] & PT_GLOBAL_MASK,
-                             gw->gfn, sw->pfn, false);
-                sw->sptep = sptep;
-                return 1;
-        }
-
-        if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
-                return 0;
-
-        if (is_large_pte(*sptep)) {
-                set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
-                kvm_flush_remote_tlbs(vcpu->kvm);
-                rmap_remove(vcpu->kvm, sptep);
-        }
+        if (!is_present_pte(gw->ptes[gw->level - 1]))
+                return NULL;
 
-        if (level == PT_DIRECTORY_LEVEL && gw->level == PT_DIRECTORY_LEVEL) {
-                metaphysical = 1;
-                if (!is_dirty_pte(gw->ptes[level - 1]))
-                        access &= ~ACC_WRITE_MASK;
-                table_gfn = gpte_to_gfn(gw->ptes[level - 1]);
-        } else {
-                metaphysical = 0;
-                table_gfn = gw->table_gfn[level - 2];
-        }
-        shadow_page = kvm_mmu_get_page(vcpu, table_gfn, (gva_t)addr, level-1,
-                                       metaphysical, access, sptep);
-        if (!metaphysical) {
-                r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 2],
-                                          &curr_pte, sizeof(curr_pte));
-                if (r || curr_pte != gw->ptes[level - 2]) {
-                        kvm_mmu_put_page(shadow_page, sptep);
-                        kvm_release_pfn_clean(sw->pfn);
-                        sw->sptep = NULL;
-                        return 1;
+        for_each_shadow_entry(vcpu, addr, iterator) {
+                level = iterator.level;
+                sptep = iterator.sptep;
+                if (level == PT_PAGE_TABLE_LEVEL
+                    || (largepage && level == PT_DIRECTORY_LEVEL)) {
+                        mmu_set_spte(vcpu, sptep, access,
+                                     gw->pte_access & access,
+                                     user_fault, write_fault,
+                                     gw->ptes[gw->level-1] & PT_DIRTY_MASK,
+                                     ptwrite, largepage,
+                                     gw->ptes[gw->level-1] & PT_GLOBAL_MASK,
+                                     gw->gfn, pfn, false);
+                        break;
                 }
-        }
 
-        spte = __pa(shadow_page->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK
-                | PT_WRITABLE_MASK | PT_USER_MASK;
-        *sptep = spte;
-        return 0;
-}
+                if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
+                        continue;
 
-static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
-                         struct guest_walker *guest_walker,
-                         int user_fault, int write_fault, int largepage,
-                         int *ptwrite, pfn_t pfn)
-{
-        struct shadow_walker walker = {
-                .walker = { .entry = FNAME(shadow_walk_entry), },
-                .guest_walker = guest_walker,
-                .user_fault = user_fault,
-                .write_fault = write_fault,
-                .largepage = largepage,
-                .ptwrite = ptwrite,
-                .pfn = pfn,
-        };
+                if (is_large_pte(*sptep)) {
+                        set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
+                        kvm_flush_remote_tlbs(vcpu->kvm);
+                        rmap_remove(vcpu->kvm, sptep);
+                }
 
-        if (!is_present_pte(guest_walker->ptes[guest_walker->level - 1]))
-                return NULL;
+                if (level == PT_DIRECTORY_LEVEL
+                    && gw->level == PT_DIRECTORY_LEVEL) {
+                        metaphysical = 1;
+                        if (!is_dirty_pte(gw->ptes[level - 1]))
+                                access &= ~ACC_WRITE_MASK;
+                        table_gfn = gpte_to_gfn(gw->ptes[level - 1]);
+                } else {
+                        metaphysical = 0;
+                        table_gfn = gw->table_gfn[level - 2];
+                }
+                shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
+                                               metaphysical, access, sptep);
+                if (!metaphysical) {
+                        r = kvm_read_guest_atomic(vcpu->kvm,
+                                                  gw->pte_gpa[level - 2],
+                                                  &curr_pte, sizeof(curr_pte));
+                        if (r || curr_pte != gw->ptes[level - 2]) {
+                                kvm_mmu_put_page(shadow_page, sptep);
+                                kvm_release_pfn_clean(pfn);
+                                sptep = NULL;
+                                break;
+                        }
+                }
 
-        walk_shadow(&walker.walker, vcpu, addr);
+                spte = __pa(shadow_page->spt)
+                        | PT_PRESENT_MASK | PT_ACCESSED_MASK
+                        | PT_WRITABLE_MASK | PT_USER_MASK;
+                *sptep = spte;
+        }
 
-        return walker.sptep;
+        return sptep;
 }
 
 /*