Typo "empty" in patch subject. On 4/30/20 5:46 PM, Igor Mammedov wrote:
Since 5.0 QEMU uses hostmem backend for allocating main guest RAM. The backend however calls mbind() which is typically NOP in case of default policy/absent host-nodes bitmap. However when runing in container with black-listed mbind() syscall, QEMU fails to start with error "cannot bind memory to host NUMA nodes: Operation not permitted" even when user hasn't provided host-nodes to pin to explictly (which is the case with -m option)To fix issue, call mbind() only in case when user has provided host-nodes explicitly (i.e. host_nodes bitmap is not empty). That should allow to run QEMU in containers with black-listed mbind() without memory pinning. If QEMU provided memory-pinning is required user still has to white-list mbind() in container configuration. Reported-by: Manuel Hohmann <mhohm...@physnet.uni-hamburg.de> Signed-off-by: Igor Mammedov <imamm...@redhat.com> --- CC: berra...@redhat.com CC: ehabk...@redhat.com CC: pbonz...@redhat.com CC: mhohm...@physnet.uni-hamburg.de CC: qemu-sta...@nongnu.org --- backends/hostmem.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 327f9eebc3..0efd7b7bd6 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -383,8 +383,10 @@ host_memory_backend_memory_complete(UserCreatable *uc, Error **errp) assert(sizeof(backend->host_nodes) >= BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long)); assert(maxnode <= MAX_NODES); - if (mbind(ptr, sz, backend->policy, - maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) { + + if (maxnode && + mbind(ptr, sz, backend->policy, backend->host_nodes, maxnode + 1, + flags)) { if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) { error_setg_errno(errp, errno, "cannot bind memory to host NUMA nodes");
