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hw/cxl: Add stub write function for RO MemoryRegionOps entries.

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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.bobo@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220817145759.32603-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jonathan Cameron 2022-08-17 15:57:57 +01:00 committed by Michael S. Tsirkin
parent d2289b524e
commit 29d1fbc6c6
1 changed files with 9 additions and 3 deletions
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12
hw/cxl/cxl-device-utils.c
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@ -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,