From 54acfac4a538365c200c80a119fd1fe87e33109c Mon Sep 17 00:00:00 2001 From: Andrea Bolognani Date: Thu, 14 Dec 2017 15:29:28 +0100 Subject: [PATCH] qemu: Invert condition nesting in qemuDomainDefValidate() While at the moment we're only performing a single check that is connected to vCPU hotplugging, we're going to introduce a second one soon. Move the topology check underneath the capability check to make that easier; since, after this change, the 'topologycpus' variable doesn't need to have function scope, we move its declaration to the inner scope as well. The comments around the check are modified in order to explain the different QEMU versions involved. Signed-off-by: Andrea Bolognani --- src/qemu/qemu_domain.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 74b82450b4..227ba32a70 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -3299,7 +3299,6 @@ qemuDomainDefValidate(const virDomainDef *def, { virQEMUDriverPtr driver = opaque; virQEMUCapsPtr qemuCaps = NULL; - unsigned int topologycpus; int ret = -1; if (!(qemuCaps = virQEMUCapsCacheLookup(driver->qemuCapsCache, @@ -3359,11 +3358,17 @@ qemuDomainDefValidate(const virDomainDef *def, } } - /* qemu as of 2.5.0 rejects SMP topologies that don't match the cpu count */ - if (virDomainDefGetVcpusTopology(def, &topologycpus) == 0 && - topologycpus != virDomainDefGetVcpusMax(def)) { - /* presence of query-hotpluggable-cpus should be a good enough witness */ - if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS)) { + /* QEMU 2.7 (detected via the availability of query-hotpluggable-cpus) + * enforces stricter rules than previous versions when it comes to guest + * CPU topology. Verify known constraints are respected */ + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS)) { + unsigned int topologycpus; + + /* Starting from QEMU 2.5, max vCPU count and overall vCPU topology + * must agree. We only actually enforce this with QEMU 2.7+, due + * to the capability check above */ + if (virDomainDefGetVcpusTopology(def, &topologycpus) == 0 && + topologycpus != virDomainDefGetVcpusMax(def)) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("CPU topology doesn't match maximum vcpu count")); goto cleanup; -- GitLab