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KVM guest: do not batch pte updates from interrupt context

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Commit b8bcfe997e 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>
This commit is contained in:
Marcelo Tosatti
2009-08-25 01:13:10 -03:00
committed by Avi Kivity
parent 65a8221163
commit 6ba6617875
1 changed files with 1 additions and 6 deletions
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7
arch/x86/kernel/kvm.c
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@@ -34,7 +34,6 @@
struct kvm_para_state { struct kvm_para_state {
u8 mmu_queue[MMU_QUEUE_SIZE]; u8 mmu_queue[MMU_QUEUE_SIZE];
int mmu_queue_len; int mmu_queue_len;
enum paravirt_lazy_mode mode;
}; };
static DEFINE_PER_CPU(struct kvm_para_state, para_state); 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(); 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); kvm_mmu_op(buffer, len);
return; return;
} }
@@ -185,10 +184,7 @@ static void kvm_release_pt(unsigned long pfn)
static void kvm_enter_lazy_mmu(void) static void kvm_enter_lazy_mmu(void)
{ {
struct kvm_para_state *state = kvm_para_state();
paravirt_enter_lazy_mmu(); paravirt_enter_lazy_mmu();
state->mode = paravirt_get_lazy_mode();
} }
static void kvm_leave_lazy_mmu(void) static void kvm_leave_lazy_mmu(void)
@@ -197,7 +193,6 @@ static void kvm_leave_lazy_mmu(void)
mmu_queue_flush(state); mmu_queue_flush(state);
paravirt_leave_lazy_mmu(); paravirt_leave_lazy_mmu();
state->mode = paravirt_get_lazy_mode();
} }
static void __init paravirt_ops_setup(void) static void __init paravirt_ops_setup(void)