Re: [PATCH v3 1/6] libxl: error out on not supported CPU mode, instead of silently ignoring

Jim Fehlig <jfehlig@xxxxxxxx> · Wed, 3 Jan 2018 17:44:33 -0700

On 12/09/2017 07:10 PM, Marek Marczykowski-Górecki wrote:
This change make libvirt XML with plain <cpu> element invalid for libxl,
which affect not only upcoming CPUID support, but also NUMA. In fact,
default mode 'custom' does not match what the driver actually does, so
it was a bug. Adjust xenconfig driver accordingly.

Should we change the default mode in the post-parse callback if NUMA or CPU 
features are defined within <cpu>? That would allow existing configs to continue 
working, although I doubt there are many since all of this is new to 3.10.0.

But nevertheless this commit break some configurations that were working
before.

I guess that is fine if we explicitly require mode='host-passthrough'.

---
Changes since v2:
  - change separated from 'libxl: add support for CPUID features policy'
---
  src/libxl/libxl_conf.c                                  | 10 ++++++++--
  src/xenconfig/xen_xl.c                                  |  1 +-
  tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml |  2 +-
  tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml  |  2 +-
  tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml  |  2 +-
  tests/xlconfigdata/test-fullvirt-vnuma.xml              |  2 +-
  6 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 970cff2..f39e783 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -353,11 +353,17 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
                            def->features[VIR_DOMAIN_FEATURE_ACPI] ==
                            VIR_TRISTATE_SWITCH_ON);
  
-        if (caps &&
-            def->cpu && def->cpu->mode == (VIR_CPU_MODE_HOST_PASSTHROUGH)) {
+        if (caps && def->cpu) {
              bool hasHwVirt = false;
              bool svm = false, vmx = false;
  
+            if (def->cpu->mode != (VIR_CPU_MODE_HOST_PASSTHROUGH)) {

While changing this the unneeded parens around VIR_CPU_MODE_HOST_PASSTHROUGH can 
be dropped.

Regards,
Jim

+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("unsupported cpu mode '%s'"),
+                               virCPUModeTypeToString(def->cpu->mode));
+                return -1;
+            }
+
              if (ARCH_IS_X86(def->os.arch)) {
                  vmx = virCPUCheckFeature(caps->host.arch, caps->host.cpu, "vmx");
                  svm = virCPUCheckFeature(caps->host.arch, caps->host.cpu, "svm");
diff --git a/src/xenconfig/xen_xl.c b/src/xenconfig/xen_xl.c
index 532d667..9e239a7 100644
--- a/src/xenconfig/xen_xl.c
+++ b/src/xenconfig/xen_xl.c
@@ -492,6 +492,7 @@ xenParseXLVnuma(virConfPtr conf,
          goto cleanup;
      }
  
+    cpu->mode = VIR_CPU_MODE_HOST_PASSTHROUGH;
      cpu->type = VIR_CPU_TYPE_GUEST;
      def->cpu = cpu;
  
diff --git a/tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml b/tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml
index e3639eb..3c486ad 100644
--- a/tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml
+++ b/tests/xlconfigdata/test-fullvirt-vnuma-autocomplete.xml
@@ -14,7 +14,7 @@
      <apic/>
      <pae/>
    </features>
-  <cpu>
+  <cpu mode='host-passthrough'>
      <numa>
        <cell id='0' cpus='0,11' memory='2097152' unit='KiB'>
          <distances>
diff --git a/tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml b/tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml
index 9cab3ca..17c9ca5 100644
--- a/tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml
+++ b/tests/xlconfigdata/test-fullvirt-vnuma-nodistances.xml
@@ -14,7 +14,7 @@
      <apic/>
      <pae/>
    </features>
-  <cpu>
+  <cpu mode='host-passthrough'>
      <numa>
        <cell id='0' cpus='0-1' memory='2097152' unit='KiB'/>
        <cell id='1' cpus='2-3' memory='2097152' unit='KiB'/>
diff --git a/tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml b/tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml
index 084b889..291fc37 100644
--- a/tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml
+++ b/tests/xlconfigdata/test-fullvirt-vnuma-partialdist.xml
@@ -14,7 +14,7 @@
      <apic/>
      <pae/>
    </features>
-  <cpu>
+  <cpu mode='host-passthrough'>
      <numa>
        <cell id='0' cpus='0-1' memory='2097152' unit='KiB'>
          <distances>
diff --git a/tests/xlconfigdata/test-fullvirt-vnuma.xml b/tests/xlconfigdata/test-fullvirt-vnuma.xml
index 5368b0d..9a9f495 100644
--- a/tests/xlconfigdata/test-fullvirt-vnuma.xml
+++ b/tests/xlconfigdata/test-fullvirt-vnuma.xml
@@ -14,7 +14,7 @@
      <apic/>
      <pae/>
    </features>
-  <cpu>
+  <cpu mode='host-passthrough'>
      <numa>
        <cell id='0' cpus='0-1' memory='2097152' unit='KiB'>
          <distances>


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