From b0ff3af4126377e3acae05d3048ea1fbdb9c8143 Mon Sep 17 00:00:00 2001
From: Jiri Denemark <jdenemar@redhat.com>
Date: Fri, 30 Sep 2022 17:59:06 +0200
Subject: [PATCH] qemu_capabilities: Translate CPU blockers
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Since commit "cpu_x86: Disable blockers from unusable CPU models"
(v3.8.0-99-g9c9620af1d) we explicitly disable CPU features reported by
QEMU as usability blockers for a particular CPU model when creating
baseline or host-model CPU definition. When QEMU changed canonical names
for some features (mostly those with '_' in their names), we forgot to
translate the blocker lists to names used by libvirt and the renamed
features would no longer be explicitly disabled in the created CPU model
even if they were reported as blockers by QEMU.

For example, on a host where EPYC CPU model has the following blockers

    <blocker name='sha-ni'/>
    <blocker name='mmxext'/>
    <blocker name='fxsr-opt'/>
    <blocker name='cr8legacy'/>
    <blocker name='sse4a'/>
    <blocker name='misalignsse'/>
    <blocker name='osvw'/>

we would fail to disable 'fxsr-opt':

    <cpu mode='custom' match='exact'>
      <model fallback='forbid'>EPYC</model>
      <feature policy='disable' name='sha-ni'/>
      <feature policy='disable' name='mmxext'/>
      <feature policy='disable' name='cr8legacy'/>
      <feature policy='disable' name='sse4a'/>
      <feature policy='disable' name='misalignsse'/>
      <feature policy='disable' name='osvw'/>
      <feature policy='disable' name='monitor'/>
    </cpu>

The 'monitor' feature is disabled even though it is not reported as a
blocker by QEMU because libvirt's definition of EPYC includes the
feature while it is missing in EPYC definition in QEMU.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/qemu/qemu_capabilities.c | 42 ++++++++++++++++++++++++++++++------
 src/qemu/qemu_capabilities.h |  4 ++++
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index ccd274b80d..6f3ff7f43f 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -2936,6 +2936,17 @@ virQEMUCapsFetchCPUDefinitions(qemuMonitor *mon,
         }
     }
 
+    for (i = 0; i < defs->ncpus; i++) {
+        qemuMonitorCPUDefInfo *cpu = &defs->cpus[i];
+        char **blocker;
+
+        if (!cpu->blockers)
+            continue;
+
+        for (blocker = cpu->blockers; *blocker; blocker++)
+            virQEMUCapsCPUFeatureFromQEMUInPlace(arch, blocker);
+    }
+
     *cpuDefs = g_steal_pointer(&defs);
     return 0;
 }
@@ -3483,6 +3494,19 @@ virQEMUCapsCPUFeatureFromQEMU(virArch arch,
 }
 
 
+void
+virQEMUCapsCPUFeatureFromQEMUInPlace(virArch arch,
+                                     char **feature)
+{
+    const char *tmp = virQEMUCapsCPUFeatureFromQEMU(arch, *feature);
+
+    if (tmp != *feature) {
+        VIR_FREE(*feature);
+        *feature = g_strdup(tmp);
+    }
+}
+
+
 /**
  * Returns  0 when host CPU model provided by QEMU was filled in qemuCaps,
  *          1 when the caller should fall back to using virCaps *->host.cpu,
@@ -3907,7 +3931,8 @@ virQEMUCapsLoadHostCPUModelInfo(virQEMUCapsAccel *caps,
 
 
 static int
-virQEMUCapsLoadCPUModels(virQEMUCapsAccel *caps,
+virQEMUCapsLoadCPUModels(virArch arch,
+                         virQEMUCapsAccel *caps,
                          xmlXPathContextPtr ctxt,
                          const char *typeStr)
 {
@@ -3978,6 +4003,8 @@ virQEMUCapsLoadCPUModels(virQEMUCapsAccel *caps,
                                      "capabilities cache"));
                     return -1;
                 }
+
+                virQEMUCapsCPUFeatureFromQEMUInPlace(arch, &cpu->blockers[j]);
             }
         }
 
@@ -4072,7 +4099,7 @@ virQEMUCapsLoadAccel(virQEMUCaps *qemuCaps,
     if (virQEMUCapsLoadHostCPUModelInfo(caps, ctxt, typeStr) < 0)
         return -1;
 
-    if (virQEMUCapsLoadCPUModels(caps, ctxt, typeStr) < 0)
+    if (virQEMUCapsLoadCPUModels(qemuCaps->arch, caps, ctxt, typeStr) < 0)
         return -1;
 
     if (virQEMUCapsLoadMachines(caps, ctxt, typeStr) < 0)
@@ -4534,7 +4561,8 @@ virQEMUCapsFormatHostCPUModelInfo(virQEMUCapsAccel *caps,
 
 
 static void
-virQEMUCapsFormatCPUModels(virQEMUCapsAccel *caps,
+virQEMUCapsFormatCPUModels(virArch arch,
+                           virQEMUCapsAccel *caps,
                            virBuffer *buf,
                            const char *typeStr)
 {
@@ -4563,8 +4591,10 @@ virQEMUCapsFormatCPUModels(virQEMUCapsAccel *caps,
             virBufferAddLit(buf, ">\n");
             virBufferAdjustIndent(buf, 2);
 
-            for (j = 0; cpu->blockers[j]; j++)
-                virBufferAsprintf(buf, "<blocker name='%s'/>\n", cpu->blockers[j]);
+            for (j = 0; cpu->blockers[j]; j++) {
+                virBufferAsprintf(buf, "<blocker name='%s'/>\n",
+                                  virQEMUCapsCPUFeatureToQEMU(arch, cpu->blockers[j]));
+            }
 
             virBufferAdjustIndent(buf, -2);
             virBufferAddLit(buf, "</cpu>\n");
@@ -4616,7 +4646,7 @@ virQEMUCapsFormatAccel(virQEMUCaps *qemuCaps,
     const char *typeStr = virQEMUCapsAccelStr(type);
 
     virQEMUCapsFormatHostCPUModelInfo(caps, buf, typeStr);
-    virQEMUCapsFormatCPUModels(caps, buf, typeStr);
+    virQEMUCapsFormatCPUModels(qemuCaps->arch, caps, buf, typeStr);
     virQEMUCapsFormatMachines(caps, buf, typeStr);
 
 }
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 904ee54f60..4b2782c462 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -845,6 +845,10 @@ const char *
 virQEMUCapsCPUFeatureFromQEMU(virArch arch,
                               const char *feature);
 
+void
+virQEMUCapsCPUFeatureFromQEMUInPlace(virArch arch,
+                                     char **feature);
+
 virSEVCapability *
 virQEMUCapsGetSEVCapabilities(virQEMUCaps *qemuCaps);