From b34cb590fb099f7929dd78d9464b70319ee12a98 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Tue, 8 Jan 2013 19:46:07 +0900 Subject: [PATCH] KVM: Make kvm_mmu_change_mmu_pages() take mmu_lock by itself No reason to make callers take mmu_lock since we do not need to protect kvm_mmu_change_mmu_pages() and kvm_mmu_slot_remove_write_access() together by mmu_lock in kvm_arch_commit_memory_region(): the former calls kvm_mmu_commit_zap_page() and flushes TLBs by itself. Note: we do not need to protect kvm->arch.n_requested_mmu_pages by mmu_lock as can be seen from the fact that it is read locklessly. Reviewed-by: Marcelo Tosatti Signed-off-by: Takuya Yoshikawa Signed-off-by: Gleb Natapov --- arch/x86/kvm/mmu.c | 4 ++++ arch/x86/kvm/x86.c | 9 ++++----- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 9c1b2d6..f557280 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2143,6 +2143,8 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages) * change the value */ + spin_lock(&kvm->mmu_lock); + if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) { while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages && !list_empty(&kvm->arch.active_mmu_pages)) { @@ -2157,6 +2159,8 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages) } kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages; + + spin_unlock(&kvm->mmu_lock); } int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index add5e48..080bbdc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3270,12 +3270,10 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, return -EINVAL; mutex_lock(&kvm->slots_lock); - spin_lock(&kvm->mmu_lock); kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages); kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages; - spin_unlock(&kvm->mmu_lock); mutex_unlock(&kvm->slots_lock); return 0; } @@ -6894,7 +6892,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, if (!kvm->arch.n_requested_mmu_pages) nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm); - spin_lock(&kvm->mmu_lock); if (nr_mmu_pages) kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages); /* @@ -6902,9 +6899,11 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, * Existing largepage mappings are destroyed here and new ones will * not be created until the end of the logging. */ - if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES)) + if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES)) { + spin_lock(&kvm->mmu_lock); kvm_mmu_slot_remove_write_access(kvm, mem->slot); - spin_unlock(&kvm->mmu_lock); + spin_unlock(&kvm->mmu_lock); + } /* * If memory slot is created, or moved, we need to clear all * mmio sptes. -- 2.7.4