[Qemu-devel] [PATCH 7/9] kvm: Switch to unlocked PIO

[Paolo Bonzini]

From: Jan Kiszka <address@hidden>

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

Signed-off-by: Jan Kiszka <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
 kvm-all.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index ca428ca..ad5ac5e 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1804,13 +1804,12 @@ int kvm_cpu_exec(CPUState *cpu)
         switch (run->exit_reason) {
         case KVM_EXIT_IO:
             DPRINTF("handle_io\n");
-            qemu_mutex_lock_iothread();
+            /* Called outside BQL */
             kvm_handle_io(run->io.port, attrs,
                           (uint8_t *)run + run->io.data_offset,
                           run->io.direction,
                           run->io.size,
                           run->io.count);
-            qemu_mutex_unlock_iothread();
             ret = 0;
             break;
         case KVM_EXIT_MMIO:
-- 
2.4.3