From: Jonathan Cameron Date: Wed, 17 Aug 2022 14:57:57 +0000 (+0100) Subject: hw/cxl: Add stub write function for RO MemoryRegionOps entries. X-Git-Tag: v7.1.0-rc4~7^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=29d1fbc6c6ff04492fc67626aec5ebf2439739d0;p=thirdparty%2Fqemu.git hw/cxl: Add stub write function for RO MemoryRegionOps entries. 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 Signed-off-by: Jonathan Cameron Message-Id: <20220817145759.32603-2-Jonathan.Cameron@huawei.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c index 687759b3017..83ce7a82708 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,