| Message ID | 20220117041050.19718-6-raphael.norwitz@nutanix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Clean up error handling in libvhost-user memory mapping | expand |
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 <stefanha@redhat.com> > Signed-off-by: Raphael Norwitz <raphael.norwitz@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 <david@redhat.com>
On 1/17/22 09:20, David Hildenbrand wrote: > 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 <stefanha@redhat.com> >> Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> >> --- >> subprojects/libvhost-user/libvhost-user.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> + 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 <david@redhat.com> > Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
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
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 <stefanha@redhat.com> Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> --- subprojects/libvhost-user/libvhost-user.c | 8 ++++++++ 1 file changed, 8 insertions(+)