From 479c2a6a296d4fafc713746bf96127c1b20c381e Mon Sep 17 00:00:00 2001

From: Avi Kivity <avi@redhat.com>

Date: Tue, 18 Oct 2011 19:43:12 +0200

Subject: [PATCH] kvm: avoid reentring kvm_flush_coalesced_mmio_buffer()

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mmio callbacks invoked by kvm_flush_coalesced_mmio_buffer() may

themselves indirectly call kvm_flush_coalesced_mmio_buffer().

Prevent reentering the function by checking a flag that indicates

we're processing coalesced mmio requests.

Signed-off-by: Avi Kivity <avi@redhat.com>

(cherry picked from commit 1cae88b9f4121c9af0bf677435c6129e643280fd)

Signed-off-by: Bruce Rogers <brogers@suse.com>

Signed-off-by: Andreas Färber <afaerber@suse.de>

---

 kvm-all.c | 10 ++++++++++

 1 file changed, 10 insertions(+)

diff --git a/kvm-all.c b/kvm-all.c

index cbc2532..26621d0 100644

--- a/kvm-all.c

+++ b/kvm-all.c

@@ -64,6 +64,7 @@ struct KVMState

     int vmfd;

     int coalesced_mmio;

     struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;

+    bool coalesced_flush_in_progress;

     int broken_set_mem_region;

     int migration_log;

     int vcpu_events;

@@ -876,6 +877,13 @@ static int kvm_handle_internal_error(CPUState *env, struct kvm_run *run)

 void kvm_flush_coalesced_mmio_buffer(void)

 {

     KVMState *s = kvm_state;

+

+    if (s->coalesced_flush_in_progress) {

+        return;

+    }

+

+    s->coalesced_flush_in_progress = true;

+

     if (s->coalesced_mmio_ring) {

         struct kvm_coalesced_mmio_ring *ring = s->coalesced_mmio_ring;

         while (ring->first != ring->last) {

@@ -888,6 +896,8 @@ void kvm_flush_coalesced_mmio_buffer(void)

             ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX;

         }

     }

+

+    s->coalesced_flush_in_progress = false;

 }

 static void do_kvm_cpu_synchronize_state(void *_env)

-- 

1.7.11.2