KVM guest: do not batch pte updates from interrupt context (6ba66178) · Commits · 戴 / test

Commit made paravirt pte updates synchronous in interrupt context. Unfortunately the KVM pv mmu code caches the lazy/nonlazy mode internally, so a pte update from interrupt context during a lazy mmu operation can be batched while it should be performed synchronously. https://bugzilla.redhat.com/show_bug.cgi?id=518022 Drop the internal mode variable and use paravirt_get_lazy_mode(), which returns the correct state. Cc: stable@kernel.org Signed-off-by:

Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:

Avi Kivity <avi@redhat.com>

arch/x86/kernel/kvm.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -34,7 +34,6 @@
		struct kvm_para_state {
		u8 mmu_queue[MMU_QUEUE_SIZE];
		int mmu_queue_len;
		enum paravirt_lazy_mode mode;
		};

		static DEFINE_PER_CPU(struct kvm_para_state, para_state);
		@@ -77,7 +76,7 @@ static void kvm_deferred_mmu_op(void *buffer, int len)
		{
		struct kvm_para_state *state = kvm_para_state();

		if (state->mode != PARAVIRT_LAZY_MMU) {
		if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU) {
		kvm_mmu_op(buffer, len);
		return;
		}
		@@ -185,10 +184,7 @@ static void kvm_release_pt(unsigned long pfn)

		static void kvm_enter_lazy_mmu(void)
		{
		struct kvm_para_state *state = kvm_para_state();

		paravirt_enter_lazy_mmu();
		state->mode = paravirt_get_lazy_mode();
		}

		static void kvm_leave_lazy_mmu(void)
		@@ -197,7 +193,6 @@ static void kvm_leave_lazy_mmu(void)

		mmu_queue_flush(state);
		paravirt_leave_lazy_mmu();
		state->mode = paravirt_get_lazy_mode();
		}

		static void __init paravirt_ops_setup(void)

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