[PATCH v4 3/9] vfio: add quirk device write method

[P J P <ppandit@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

Add vfio quirk device mmio write method to avoid NULL pointer
dereference issue.

Reported-by: Lei Sun <slei.casper@gmail.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/vfio/pci-quirks.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Update v4: log guest_error and add Reviewed-by tag
  -> https://lists.nongnu.org/archive/html/qemu-devel/2020-07/msg05326.html

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index 3a14b7c303..9b162cc3f9 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -14,6 +14,7 @@
 #include "config-devices.h"
 #include "exec/memop.h"
 #include "qemu/units.h"
+#include "qemu/log.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
@@ -264,8 +265,15 @@ static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
     return data;
 }
 
+static void vfio_ati_3c3_quirk_write(void *opaque, hwaddr addr,
+                                        uint64_t data, unsigned size)
+{
+    qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid access\n", __func__);
+}
+
 static const MemoryRegionOps vfio_ati_3c3_quirk = {
     .read = vfio_ati_3c3_quirk_read,
+    .write = vfio_ati_3c3_quirk_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
-- 
2.26.2