From b072cbf0233b1fd9d84730cbe5cd1706dcacd354 Mon Sep 17 00:00:00 2001 From: Bibo Mao Date: Tue, 9 Jul 2024 16:25:51 +0800 Subject: LoongArch: KVM: Discard dirty page tracking on readonly memslot For readonly memslot such as UEFI BIOS or UEFI var space, guest cannot write this memory space directly. So it is not necessary to track dirty pages for readonly memslot. Here we make such optimization in function kvm_arch_commit_memory_region(). Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen --- arch/loongarch/kvm/mmu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'arch/loongarch/kvm') diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c index 576bc90292f0..5fa8e3b36121 100644 --- a/arch/loongarch/kvm/mmu.c +++ b/arch/loongarch/kvm/mmu.c @@ -444,6 +444,17 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, enum kvm_mr_change change) { int needs_flush; + u32 old_flags = old ? old->flags : 0; + u32 new_flags = new ? new->flags : 0; + bool log_dirty_pages = new_flags & KVM_MEM_LOG_DIRTY_PAGES; + + /* Only track memslot flags changed */ + if (change != KVM_MR_FLAGS_ONLY) + return; + + /* Discard dirty page tracking on readonly memslot */ + if ((old_flags & new_flags) & KVM_MEM_READONLY) + return; /* * If dirty page logging is enabled, write protect all pages in the slot @@ -454,9 +465,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, * MOVE/DELETE: The old mappings will already have been cleaned up by * kvm_arch_flush_shadow_memslot() */ - if (change == KVM_MR_FLAGS_ONLY && - (!(old->flags & KVM_MEM_LOG_DIRTY_PAGES) && - new->flags & KVM_MEM_LOG_DIRTY_PAGES)) { + if (!(old_flags & KVM_MEM_LOG_DIRTY_PAGES) && log_dirty_pages) { spin_lock(&kvm->mmu_lock); /* Write protect GPA page table entries */ needs_flush = kvm_mkclean_gpa_pt(kvm, new->base_gfn, -- cgit v1.2.3-70-g09d2