KVM: x86: MMU: Move mapping_level_dirty_bitmap() call in mapping_level()

This is necessary to eliminate an extra memory slot search later.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2262728863de51eb3436e936bd6bd51b462ac908..890cd694c9a2867a2e84749b1ab644fe6f7b3a3c 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -870,10 +870,16 @@ static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
        return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
 }
 
-static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
+static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
+                        bool *force_pt_level)
 {
        int host_level, level, max_level;
 
+       if (likely(!*force_pt_level))
+               *force_pt_level = mapping_level_dirty_bitmap(vcpu, large_gfn);
+       if (unlikely(*force_pt_level))
+               return PT_PAGE_TABLE_LEVEL;
+
        host_level = host_mapping_level(vcpu->kvm, large_gfn);
 
        if (host_level == PT_PAGE_TABLE_LEVEL)
@@ -2962,14 +2968,13 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
 {
        int r;
        int level;
-       bool force_pt_level;
+       bool force_pt_level = false;
        pfn_t pfn;
        unsigned long mmu_seq;
        bool map_writable, write = error_code & PFERR_WRITE_MASK;
 
-       force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
+       level = mapping_level(vcpu, gfn, &force_pt_level);
        if (likely(!force_pt_level)) {
-               level = mapping_level(vcpu, gfn);
                /*
                 * This path builds a PAE pagetable - so we can map
                 * 2mb pages at maximum. Therefore check if the level
@@ -2979,8 +2984,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
                        level = PT_DIRECTORY_LEVEL;
 
                gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
-       } else
-               level = PT_PAGE_TABLE_LEVEL;
+       }
 
        if (fast_page_fault(vcpu, v, level, error_code))
                return 0;
@@ -3495,20 +3499,15 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
        if (r)
                return r;
 
-       if (mapping_level_dirty_bitmap(vcpu, gfn) ||
-           !check_hugepage_cache_consistency(vcpu, gfn, PT_DIRECTORY_LEVEL))
-               force_pt_level = true;
-       else
-               force_pt_level = false;
-
+       force_pt_level = !check_hugepage_cache_consistency(vcpu, gfn,
+                                                          PT_DIRECTORY_LEVEL);
+       level = mapping_level(vcpu, gfn, &force_pt_level);
        if (likely(!force_pt_level)) {
-               level = mapping_level(vcpu, gfn);
                if (level > PT_DIRECTORY_LEVEL &&
                    !check_hugepage_cache_consistency(vcpu, gfn, level))
                        level = PT_DIRECTORY_LEVEL;
                gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
-       } else
-               level = PT_PAGE_TABLE_LEVEL;
+       }
 
        if (fast_page_fault(vcpu, gpa, level, error_code))
                return 0;

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 8ebc3a5560cec96c73e8b1e1b7d6caf9a14455ab..bf39d0f3efa9ca9595084f5270c51e27c806b270 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -744,9 +744,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
              &walker, user_fault, &vcpu->arch.write_fault_to_shadow_pgtable);
 
        if (walker.level >= PT_DIRECTORY_LEVEL && !is_self_change_mapping) {
-               force_pt_level = mapping_level_dirty_bitmap(vcpu, walker.gfn);
-               if (!force_pt_level) {
-                       level = min(walker.level, mapping_level(vcpu, walker.gfn));
+               level = mapping_level(vcpu, walker.gfn, &force_pt_level);
+               if (likely(!force_pt_level)) {
+                       level = min(walker.level, level);
                        walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
                }
        } else