From: Raphael Norwitz <raphael.norw...@nutanix.com>
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>
Message-Id: <20220117041050.19718-6-raphael.norw...@nutanix.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Reviewed-by: David Hildenbrand <da...@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
---
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");
+ return false;
+ }
+
/*
* If we are in postcopy mode and we receive a u64 payload with a 0 value
* we know all the postcopy client bases have been received, and we
--
MST
