On Wed, 10 Jan 2018 00:39:35 +0800 Jay Zhou <jianjay.z...@huawei.com> wrote:
> Start QEMU with more DIMM devices than limit but without any > vhost backends and then hotplug a vhost user backend, the VM > will be crashed. > Instead of asserting in vhost_user_set_mem_table(), error number > is used to gracefully prevent device to start. This fixes the > crash issue. I'd rewrite commit message as following: -- QEMU will assert on vhsot-user backed virtio device hotplug if QEMU is using more RAM regions than VHOST_MEMORY_MAX_NREGIONS (for example if it were started with a lot of DIMM devices). Fix it by returning error instead of asserting and let callers of vhost_set_mem_table() handle error condition gracefully. -- > > Cc: qemu-sta...@nongnu.org > Signed-off-by: Igor Mammedov <imamm...@redhat.com> > Signed-off-by: Jay Zhou <jianjay.z...@huawei.com> > --- > hw/virtio/vhost-user.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index 093675e..8500562 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -317,11 +317,14 @@ static int vhost_user_set_mem_table(struct vhost_dev > *dev, > &offset); > fd = memory_region_get_fd(mr); > if (fd > 0) { > + if (fd_num == VHOST_MEMORY_MAX_NREGIONS) { > + error_report("Failed preparing vhost-user memory table msg"); > + return -1; > + } > msg.payload.memory.regions[fd_num].userspace_addr = > reg->userspace_addr; > msg.payload.memory.regions[fd_num].memory_size = > reg->memory_size; > msg.payload.memory.regions[fd_num].guest_phys_addr = > reg->guest_phys_addr; > msg.payload.memory.regions[fd_num].mmap_offset = offset; > - assert(fd_num < VHOST_MEMORY_MAX_NREGIONS); > fds[fd_num++] = fd; > } > }