[libvirt] [PATCH v3.1 3/6] libxl: add support for CPUID features policy

[Marek Marczykowski-Górecki]

Convert CPU features policy into libxl cpuid policy settings. Use new
("libxl") syntax, which allow to enable/disable specific bits, using
host CPU as a base. For this reason, only "host-passthrough" mode is
accepted.
Libxl do not have distinction between "force" and "required" policy
(there is only "force") and also between "forbid" and "disable" (there
is only "disable"). So, merge them appropriately. If anything, "require"
and "forbid" should be enforced outside of specific driver.

Signed-off-by: Marek Marczykowski-Górecki <marmarek at invisiblethingslab.com>
---
Changes since v3:
 - compile fix (one more s/libxlTranslateCPUFeature/xenTranslateCPUFeature/)
Changes since v2:
 - drop spurious changes
 - move libxlTranslateCPUFeature function to xen_xl.c, to be reused by
 xenconfig driver
Changes since v1:
 - use new ("libxl") syntax to set only bits explicitly mentioned in
 domain XML
---
 src/libxl/libxl_conf.c | 35 +++++++++++++++++++++++++++++++++--
 src/xenconfig/xen_xl.c | 34 ++++++++++++++++++++++++++++++++++
 src/xenconfig/xen_xl.h |  2 ++
 3 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 184610966..5eae6d10f 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -50,6 +50,7 @@
 #include "secret_util.h"
 #include "cpu/cpu.h"
 #include "xen_common.h"
+#include "xen_xl.h"
 
 
 #define VIR_FROM_THIS VIR_FROM_LIBXL
@@ -357,6 +358,7 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
             bool hasHwVirt = false;
             int nested_hvm = -1;
             bool svm = false, vmx = false;
+            char xlCPU[32];
 
             if (def->cpu->mode != (VIR_CPU_MODE_HOST_PASSTHROUGH)) {
                 virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@@ -379,15 +381,44 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
                         case VIR_CPU_FEATURE_DISABLE:
                         case VIR_CPU_FEATURE_FORBID:
                             if ((vmx && STREQ(def->cpu->features[i].name, "vmx")) ||
-                                (svm && STREQ(def->cpu->features[i].name, "svm")))
+                                (svm && STREQ(def->cpu->features[i].name, "svm"))) {
                                 nested_hvm = 0;
+                                continue;
+                            }
+
+                            snprintf(xlCPU,
+                                    sizeof(xlCPU),
+                                    "%s=0",
+                                    xenTranslateCPUFeature(
+                                        def->cpu->features[i].name,
+                                        false));
+                            if (libxl_cpuid_parse_config(&b_info->cpuid, xlCPU)) {
+                                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                        _("unsupported cpu feature '%s'"),
+                                        def->cpu->features[i].name);
+                                return -1;
+                            }
                             break;
 
                         case VIR_CPU_FEATURE_FORCE:
                         case VIR_CPU_FEATURE_REQUIRE:
                             if ((vmx && STREQ(def->cpu->features[i].name, "vmx")) ||
-                                (svm && STREQ(def->cpu->features[i].name, "svm")))
+                                (svm && STREQ(def->cpu->features[i].name, "svm"))) {
                                 nested_hvm = 1;
+                                continue;
+                            }
+
+                            snprintf(xlCPU,
+                                    sizeof(xlCPU),
+                                    "%s=1",
+                                    xenTranslateCPUFeature(
+                                        def->cpu->features[i].name, false));
+                            if (libxl_cpuid_parse_config(&b_info->cpuid, xlCPU)) {
+                                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                        _("unsupported cpu feature '%s'"),
+                                        def->cpu->features[i].name);
+                                return -1;
+                            }
                             break;
                         case VIR_CPU_FEATURE_OPTIONAL:
                         case VIR_CPU_FEATURE_LAST:
diff --git a/src/xenconfig/xen_xl.c b/src/xenconfig/xen_xl.c
index 317c7a08d..356ca3a4b 100644
--- a/src/xenconfig/xen_xl.c
+++ b/src/xenconfig/xen_xl.c
@@ -225,6 +225,40 @@ xenParseXLOS(virConfPtr conf, virDomainDefPtr def, virCapsPtr caps)
     return 0;
 }
 
+/*
+ * Translate CPU feature name from libvirt to libxl (from_libxl=false) or from
+ * libxl to libvirt (from_libxl=true).
+ */
+const char *
+xenTranslateCPUFeature(const char *feature_name, bool from_libxl)
+{
+    static const char *translation_table[][2] = {
+        /* libvirt name, libxl name */
+        { "cx16", "cmpxchg16" },
+        { "cid", "cntxid" },
+        { "ds_cpl", "dscpl" },
+        { "pclmuldq", "pclmulqdq" },
+        { "pni", "sse3" },
+        { "ht", "htt" },
+        { "pn", "psn" },
+        { "clflush", "clfsh" },
+        { "sep", "sysenter" },
+        { "cx8", "cmpxchg8" },
+        { "nodeid_msr", "nodeid" },
+        { "cr8legacy", "altmovcr8" },
+        { "lahf_lm", "lahfsahf" },
+        { "cmp_legacy", "cmplegacy" },
+        { "fxsr_opt", "ffxsr" },
+        { "pdpe1gb", "page1gb" },
+    };
+    size_t i;
+
+    for (i = 0; i < ARRAY_CARDINALITY(translation_table); i++)
+        if (STREQ(translation_table[i][from_libxl], feature_name))
+            return translation_table[i][!from_libxl];
+    return feature_name;
+}
+
 
 static int
 xenParseXLSpice(virConfPtr conf, virDomainDefPtr def)
diff --git a/src/xenconfig/xen_xl.h b/src/xenconfig/xen_xl.h
index dd963268e..68f332aca 100644
--- a/src/xenconfig/xen_xl.h
+++ b/src/xenconfig/xen_xl.h
@@ -33,4 +33,6 @@ virDomainDefPtr xenParseXL(virConfPtr conn,
 
 virConfPtr xenFormatXL(virDomainDefPtr def, virConnectPtr);
 
+const char *xenTranslateCPUFeature(const char *feature_name, bool from_libxl);
+
 #endif /* __VIR_XEN_XL_H__ */
-- 
2.13.6