On 17.01.22 05:12, Raphael Norwitz wrote:
> When VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS support was added to
> libvhost-user, no guardrails were added to protect against QEMU
> attempting to hot-add too many RAM slots to a VM with a libvhost-user
> based backed attached.
>
> This change adds the missing error handling by introducing a check on
> the number of RAM slots the device has available before proceeding to
> process the VHOST_USER_ADD_MEM_REG message.
>
> Suggested-by: Stefan Hajnoczi <stefa...@redhat.com>
> Signed-off-by: Raphael Norwitz <raphael.norw...@nutanix.com>
> ---
> subprojects/libvhost-user/libvhost-user.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/subprojects/libvhost-user/libvhost-user.c
> b/subprojects/libvhost-user/libvhost-user.c
> index 3f4d7221ca..2a1fa00a44 100644
> --- a/subprojects/libvhost-user/libvhost-user.c
> +++ b/subprojects/libvhost-user/libvhost-user.c
> @@ -705,6 +705,14 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
> return false;
> }
>
> + if (dev->nregions == VHOST_USER_MAX_RAM_SLOTS) {
> + close(vmsg->fds[0]);
> + vu_panic(dev, "failing attempt to hot add memory via "
> + "VHOST_USER_ADD_MEM_REG message because the backend
> has "
> + "no free ram slots available");
Maybe simply "VHOST_USER_ADD_MEM_REG failed because there are no free
ram slots"
Reviewed-by: David Hildenbrand <da...@redhat.com>
--
Thanks,
David / dhildenb
