From: Jonathan Cameron <jonathan.came...@huawei.com>
There is no checking on the availability of a write callback.
Hence QEMU crashes if a write does occur to one of these regions.
Discovered whilst chasing a Linux kernel bug that incorrectly
wrote into one of these regions.
Fixes: 6364adacdf ("hw/cxl/device: Implement the CAP array (8.2.8.1-2)")
Reported-by: Bobo WL <lmw.b...@gmail.com>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
Message-Id: <20220817145759.32603-2-jonathan.came...@huawei.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
hw/cxl/cxl-device-utils.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c
index 687759b301..83ce7a8270 100644
--- a/hw/cxl/cxl-device-utils.c
+++ b/hw/cxl/cxl-device-utils.c
@@ -141,9 +141,15 @@ static uint64_t mdev_reg_read(void *opaque, hwaddr offset,
unsigned size)
return retval;
}
+static void ro_reg_write(void *opaque, hwaddr offset, uint64_t value,
+ unsigned size)
+{
+ /* Many register sets are read only */
+}
+
static const MemoryRegionOps mdev_ops = {
.read = mdev_reg_read,
- .write = NULL, /* memory device register is read only */
+ .write = ro_reg_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.valid = {
.min_access_size = 1,
@@ -173,7 +179,7 @@ static const MemoryRegionOps mailbox_ops = {
static const MemoryRegionOps dev_ops = {
.read = dev_reg_read,
- .write = NULL, /* status register is read only */
+ .write = ro_reg_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.valid = {
.min_access_size = 1,
@@ -188,7 +194,7 @@ static const MemoryRegionOps dev_ops = {
static const MemoryRegionOps caps_ops = {
.read = caps_reg_read,
- .write = NULL, /* caps registers are read only */
+ .write = ro_reg_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.valid = {
.min_access_size = 1,
--
MST
