[libvirt PATCH] qemu: Do not set default CPU for archs without CPU driver

Jiri Denemark jdenemar at redhat.com
Tue Feb 25 15:45:50 UTC 2020


Whenever there is a guest CPU configured in domain XML, we will call
some CPU driver APIs to validate the CPU definition and check its
compatibility with the hypervisor. Thus domains with guest CPU
specification can only be started if the guest architecture is supported
by the CPU driver. But we would add a default CPU to any domain as long
as QEMU reports it causing failures to start any domain on affected
architectures.

https://bugzilla.redhat.com/show_bug.cgi?id=1805755

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
---
 src/cpu/cpu.c            | 24 ++++++++++++++++++++++++
 src/cpu/cpu.h            |  3 +++
 src/libvirt_private.syms |  1 +
 src/qemu/qemu_domain.c   |  3 +++
 4 files changed, 31 insertions(+)

diff --git a/src/cpu/cpu.c b/src/cpu/cpu.c
index ae3a0acc10..6d6191fe4e 100644
--- a/src/cpu/cpu.c
+++ b/src/cpu/cpu.c
@@ -1096,3 +1096,27 @@ virCPUDataAddFeature(virCPUDataPtr cpuData,
 
     return driver->dataAddFeature(cpuData, name);
 }
+
+
+/**
+ * virCPUArchIsSupported:
+ *
+ * @arch: CPU architecture
+ *
+ * Returns true if the architecture is supported by any CPU driver.
+ */
+bool
+virCPUArchIsSupported(virArch arch)
+{
+    size_t i;
+    size_t j;
+
+    for (i = 0; i < G_N_ELEMENTS(drivers); i++) {
+        for (j = 0; j < drivers[i]->narch; j++) {
+            if (arch == drivers[i]->arch[j])
+                return true;
+        }
+    }
+
+    return false;
+}
diff --git a/src/cpu/cpu.h b/src/cpu/cpu.h
index 2e8b8923ae..f779d2be17 100644
--- a/src/cpu/cpu.h
+++ b/src/cpu/cpu.h
@@ -265,6 +265,9 @@ int
 virCPUDataAddFeature(virCPUDataPtr cpuData,
                      const char *name);
 
+bool
+virCPUArchIsSupported(virArch arch);
+
 /* virCPUDataFormat and virCPUDataParse are implemented for unit tests only and
  * have no real-life usage
  */
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 9d172d3bd0..e27b6f29bc 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1309,6 +1309,7 @@ virStoragePoolObjVolumeListExport;
 # cpu/cpu.h
 cpuDecode;
 cpuEncode;
+virCPUArchIsSupported;
 virCPUBaseline;
 virCPUCheckFeature;
 virCPUCompare;
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 446a517df9..7d274a4fa5 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4576,6 +4576,9 @@ qemuDomainDefSetDefaultCPU(virDomainDefPtr def,
          def->cpu->model))
         return 0;
 
+    if (!virCPUArchIsSupported(def->os.arch))
+        return 0;
+
     /* Default CPU model info from QEMU is usable for TCG only except for
      * x86, s390, and ppc64. */
     if (!ARCH_IS_X86(def->os.arch) &&
-- 
2.25.1




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