diff mbox

[v2,2/2] KVM: x86: Avoid zapping mmio sptes twice for generation wraparound

Message ID 20130704134126.394b3e67.yoshikawa_takuya_b1@lab.ntt.co.jp (mailing list archive)
State New, archived
Headers show

Commit Message

Takuya Yoshikawa July 4, 2013, 4:41 a.m. UTC 
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>
---
 arch/x86/kvm/mmu.c |    5 +----
 arch/x86/kvm/x86.c |   10 +++++-----
 2 files changed, 6 insertions(+), 9 deletions(-)

Comments

Xiao Guangrong July 4, 2013, 10:27 a.m. UTC | #1 
On 07/04/2013 12:41 PM, Takuya Yoshikawa wrote:
> 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.
> 

Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>

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diff mbox

Patch

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0d094da..bf7af1e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4383,11 +4383,8 @@  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);
 	}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 71912c9..9be6621 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7022,6 +7022,11 @@  out_free:
 
 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,
@@ -7084,11 +7089,6 @@  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)