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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: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Takuya Yoshikawa 2013-07-04 13:41:26 +09:00 committed by Paolo Bonzini
parent e59dbe09f8
commit e6dff7d15e
2 changed files with 6 additions and 9 deletions
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5
arch/x86/kvm/mmu.c
View File

@ -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);
}

10
arch/x86/kvm/x86.c
View File

@ -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)