[Qemu-devel] [PATCH 9/9] kvm: Switch to unlocked MMIO

[Paolo Bonzini <pbonzini@redhat.com>]

Do not take the BQL before dispatching MMIO requests of KVM VCPUs.
Instead, address_space_rw will do it if necessary. This enables completely
BQL-free MMIO handling in KVM mode for upcoming devices with fine-grained
locking.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1434646046-27150-10-git-send-email-pbonzini@redhat.com>
---
 kvm-all.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index 07bdcfa..9053ef9 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1811,13 +1811,12 @@ int kvm_cpu_exec(CPUState *cpu)
             break;
         case KVM_EXIT_MMIO:
             DPRINTF("handle_mmio\n");
-            qemu_mutex_lock_iothread();
+            /* Called outside BQL */
             address_space_rw(&address_space_memory,
                              run->mmio.phys_addr, attrs,
                              run->mmio.data,
                              run->mmio.len,
                              run->mmio.is_write);
-            qemu_mutex_unlock_iothread();
             ret = 0;
             break;
         case KVM_EXIT_IRQ_WINDOW_OPEN:
-- 
1.8.3.1