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Commit e6dff7d1 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Paolo Bonzini
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KVM: x86: Avoid zapping mmio sptes twice for generation wraparound 



Now that kvm_arch_memslots_updated() catches every increment of the
memslots->generation, checking if the mmio generation has reached its
maximum value is enough.

Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e59dbe09

arch/x86/kvm/mmu.c

+1 −4
Original line number Diff line number Diff line
@@ -4390,11 +4390,8 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm) 
	/*

	 * The very rare case: if the generation-number is round,

	 * zap all shadow pages.

	 *

	 * The max value is MMIO_MAX_GEN - 1 since it is not called

	 * when mark memslot invalid.

	 */

	if (unlikely(kvm_current_mmio_generation(kvm) >= (MMIO_MAX_GEN - 1))) {

	if (unlikely(kvm_current_mmio_generation(kvm) >= MMIO_MAX_GEN)) {

		printk_ratelimited(KERN_INFO "kvm: zapping shadow pages for mmio generation wraparound\n");

		kvm_mmu_invalidate_zap_all_pages(kvm);

	}

arch/x86/kvm/x86.c

+5 −5
Original line number Diff line number Diff line
@@ -7021,6 +7021,11 @@ int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages) 


void kvm_arch_memslots_updated(struct kvm *kvm)

{

	/*

	 * memslots->generation has been incremented.

	 * mmio generation may have reached its maximum value.

	 */

	kvm_mmu_invalidate_mmio_sptes(kvm);

}



int kvm_arch_prepare_memory_region(struct kvm *kvm,
@@ -7083,11 +7088,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, 
	 */

	if ((change != KVM_MR_DELETE) && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))

		kvm_mmu_slot_remove_write_access(kvm, mem->slot);

	/*

	 * If memory slot is created, or moved, we need to clear all

	 * mmio sptes.

	 */

	kvm_mmu_invalidate_mmio_sptes(kvm);

}



void kvm_arch_flush_shadow_all(struct kvm *kvm)