From 06e4ed9270d49adc928c7e9aa0655c23f59b6920 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 28 Feb 2012 12:53:18 +0100 Subject: [PATCH 5/7] kvm: avoid reentring kvm_flush_coalesced_mmio_buffer() RH-Author: Paolo Bonzini Message-id: <1330433598-21534-6-git-send-email-pbonzini@redhat.com> Patchwork-id: 37672 O-Subject: [RHEL 6.3 qemu-kvm PATCH 5/5] kvm: avoid reentring kvm_flush_coalesced_mmio_buffer() Bugzilla: 796575 RH-Acked-by: Alex Williamson RH-Acked-by: Laszlo Ersek RH-Acked-by: Markus Armbruster From: Avi Kivity 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 (cherry picked from commit 1cae88b9f4121c9af0bf677435c6129e643280fd) Signed-off-by: Paolo Bonzini --- kvm-all.c | 10 ++++++++++ qemu-kvm.c | 8 ++++++++ qemu-kvm.h | 1 + 3 files changed, 19 insertions(+), 0 deletions(-) Signed-off-by: Michal Novotny --- kvm-all.c | 10 ++++++++++ qemu-kvm.c | 8 ++++++++ qemu-kvm.h | 1 + 3 files changed, 19 insertions(+), 0 deletions(-) diff --git a/kvm-all.c b/kvm-all.c index a50ec56..5c56e1a 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -65,6 +65,7 @@ struct KVMState #ifdef KVM_CAP_COALESCED_MMIO struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; #endif + bool coalesced_flush_in_progress; int broken_set_mem_region; int migration_log; int vcpu_events; @@ -602,6 +603,13 @@ void kvm_flush_coalesced_mmio_buffer(void) { #ifdef KVM_CAP_COALESCED_MMIO 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) { @@ -614,6 +622,8 @@ void kvm_flush_coalesced_mmio_buffer(void) ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX; } } + + s->coalesced_flush_in_progress = false; #endif } diff --git a/qemu-kvm.c b/qemu-kvm.c index ba5a037..6edb5f8 100644 --- a/qemu-kvm.c +++ b/qemu-kvm.c @@ -970,6 +970,12 @@ static int kvm_handle_internal_error(kvm_context_t kvm, void kvm_flush_coalesced_mmio_buffer(void) { #if defined(KVM_CAP_COALESCED_MMIO) + if (kvm_state->coalesced_flush_in_progress) { + return; + } + + kvm_state->coalesced_flush_in_progress = true; + if (kvm_state->coalesced_mmio) { struct kvm_coalesced_mmio_ring *ring = kvm_state->coalesced_mmio_ring; while (ring->first != ring->last) { @@ -980,6 +986,8 @@ void kvm_flush_coalesced_mmio_buffer(void) ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX; } } + + kvm_state->coalesced_flush_in_progress = false; #endif } diff --git a/qemu-kvm.h b/qemu-kvm.h index 3be5fd0..738e2fb 100644 --- a/qemu-kvm.h +++ b/qemu-kvm.h @@ -1176,6 +1176,7 @@ typedef struct KVMState { #ifdef KVM_CAP_COALESCED_MMIO struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; #endif + bool coalesced_flush_in_progress; int broken_set_mem_region; int migration_log; int vcpu_events; -- 1.7.7.6