[Qemu-devel] [PATCH v4 4/4] ivshmem: Disable irqfd on device reset

[Ladi Prosek <lprosek@redhat.com>]

The effects of ivshmem_enable_irqfd() was not undone on device reset.

This manifested as:
ivshmem_add_kvm_msi_virq: Assertion `!s->msi_vectors[vector].pdev' failed.

when irqfd was enabled before reset and then enabled again after reset, making
ivshmem_enable_irqfd() run for the second time.

To reproduce, run:

  ivshmem-server

and QEMU with:

  -device ivshmem-doorbell,chardev=iv
  -chardev socket,path=/tmp/ivshmem_socket,id=iv

then install the Windows driver, at the time of writing available at:

https://github.com/virtio-win/kvm-guest-drivers-windows/tree/master/ivshmem

and crash-reboot the guest by inducing a BSOD.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
---
 hw/misc/ivshmem.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index d1bb246d12..9c7e74ef12 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -758,10 +758,14 @@ static void ivshmem_msix_vector_use(IVShmemState *s)
     }
 }
 
+static void ivshmem_disable_irqfd(IVShmemState *s);
+
 static void ivshmem_reset(DeviceState *d)
 {
     IVShmemState *s = IVSHMEM_COMMON(d);
 
+    ivshmem_disable_irqfd(s);
+
     s->intrstatus = 0;
     s->intrmask = 0;
     if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
-- 
2.13.6