From 5225fdf8c8bea4418f69875804584c89a27c170e Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Fri, 16 Oct 2015 17:08:03 +0900 Subject: [PATCH] KVM: x86: MMU: Eliminate an extra memory slot search in mapping_level() Calling kvm_vcpu_gfn_to_memslot() twice in mapping_level() should be avoided since getting a slot by binary search may not be negligible, especially for virtual machines with many memory slots. Signed-off-by: Takuya Yoshikawa Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 09833b0..dd2a7c6 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -818,14 +818,11 @@ static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp) kvm->arch.indirect_shadow_pages--; } -static int has_wrprotected_page(struct kvm_vcpu *vcpu, - gfn_t gfn, - int level) +static int __has_wrprotected_page(gfn_t gfn, int level, + struct kvm_memory_slot *slot) { - struct kvm_memory_slot *slot; struct kvm_lpage_info *linfo; - slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); if (slot) { linfo = lpage_info_slot(gfn, slot, level); return linfo->write_count; @@ -834,6 +831,14 @@ static int has_wrprotected_page(struct kvm_vcpu *vcpu, return 1; } +static int has_wrprotected_page(struct kvm_vcpu *vcpu, gfn_t gfn, int level) +{ + struct kvm_memory_slot *slot; + + slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + return __has_wrprotected_page(gfn, level, slot); +} + static int host_mapping_level(struct kvm *kvm, gfn_t gfn) { unsigned long page_size; @@ -896,7 +901,7 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn, max_level = min(kvm_x86_ops->get_lpage_level(), host_level); for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level) - if (has_wrprotected_page(vcpu, large_gfn, level)) + if (__has_wrprotected_page(large_gfn, level, slot)) break; return level - 1; -- 2.7.4