[libvirt PATCH 3/3] cpu: Honor check='full' for host-passthrough CPUs

[Jiri Denemark]

The check attribute was completely ignored for host-passthrough CPUs
even if they explicitly requested some features to be enabled. For
example, a domain with the following CPU definition

  <cpu mode='host-passthrough' check='full'>
    <feature policy='require' name='svm'/>
  </cpu>

would happily start even when 'svm' cannot be enabled.

Let's call virCPUArchUpdateLive for host-passthrough CPUs with
VIR_CPU_CHECK_FULL to make sure the architecture specific code can
validate the provided virtual CPU against the desired definition.

https://bugzilla.redhat.com/show_bug.cgi?id=1515677

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
---
 src/cpu/cpu.c     |  3 ++-
 src/cpu/cpu_x86.c | 10 +++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/cpu/cpu.c b/src/cpu/cpu.c
index c461c4839d..631c755391 100644
--- a/src/cpu/cpu.c
+++ b/src/cpu/cpu.c
@@ -647,7 +647,8 @@ virCPUUpdateLive(virArch arch,
     if (!driver->updateLive)
         return 1;
 
-    if (cpu->mode == VIR_CPU_MODE_CUSTOM) {
+    if (cpu->mode == VIR_CPU_MODE_CUSTOM ||
+        cpu->check == VIR_CPU_CHECK_FULL) {
         if (driver->updateLive(cpu, dataEnabled, dataDisabled) < 0)
             return -1;
 
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index 5a6b7bb1d8..7a8a2e3f3b 100644
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -3009,8 +3009,10 @@ virCPUx86UpdateLive(virCPUDefPtr cpu,
                     virCPUDataPtr dataEnabled,
                     virCPUDataPtr dataDisabled)
 {
+    bool hostPassthrough = cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH;
     virCPUx86MapPtr map;
     virCPUx86ModelPtr model = NULL;
+    virCPUx86ModelPtr modelDisabled = NULL;
     virCPUx86Data enabled = VIR_CPU_X86_DATA_INIT;
     virCPUx86Data disabled = VIR_CPU_X86_DATA_INIT;
     virBuffer bufAdded = VIR_BUFFER_INITIALIZER;
@@ -3026,6 +3028,10 @@ virCPUx86UpdateLive(virCPUDefPtr cpu,
     if (!(model = x86ModelFromCPU(cpu, map, -1)))
         goto cleanup;
 
+    if (hostPassthrough &&
+        !(modelDisabled = x86ModelFromCPU(cpu, map, VIR_CPU_FEATURE_DISABLE)))
+        goto cleanup;
+
     if (dataEnabled &&
         x86DataCopy(&enabled, &dataEnabled->data.x86) < 0)
         goto cleanup;
@@ -3040,7 +3046,8 @@ virCPUx86UpdateLive(virCPUDefPtr cpu,
 
         if (x86DataIsSubset(&model->data, &feature->data))
             expected = VIR_CPU_FEATURE_REQUIRE;
-        else
+        else if (!hostPassthrough ||
+                 x86DataIsSubset(&modelDisabled->data, &feature->data))
             expected = VIR_CPU_FEATURE_DISABLE;
 
         if (expected == VIR_CPU_FEATURE_DISABLE &&
@@ -3101,6 +3108,7 @@ virCPUx86UpdateLive(virCPUDefPtr cpu,
 
  cleanup:
     x86ModelFree(model);
+    x86ModelFree(modelDisabled);
     virCPUx86DataClear(&enabled);
     virCPUx86DataClear(&disabled);
     VIR_FREE(added);
-- 
2.25.1