[libvirt] [PATCH v2 1/3] libxl: set nestedhvm for mode host-passthrough

[Wim Ten Have]

From: Wim ten Have <wim.ten.have at oracle.com>

Xen feature nestedhvm is the option on Xen 4.4+ which enables
nested virtualization when mode host-passthrough is applied.

Virtualization on target domain can be disabled by specifying
such under feature policy rule on target name;

[On Intel (VT-x) architecture]
<feature policy='disable' name='vmx'/>

or:

[On AMD (AMD-V) architecture]
<feature policy='disable' name='svm'/>

Signed-off-by: Joao Martins <joao.m.martins at oracle.com>
Signed-off-by: Wim ten Have <wim.ten.have at oracle.com>
---
 src/libxl/libxl_conf.c   | 47 ++++++++++++++++++++++++++++++++++++++++++-----
 src/libxl/libxl_conf.h   |  2 +-
 src/libxl/libxl_domain.c |  2 +-
 3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index f5b788b..ede7c8a 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -47,6 +47,7 @@
 #include "libxl_utils.h"
 #include "virstoragefile.h"
 #include "secret_util.h"
+#include "cpu/cpu.h"
 
 
 #define VIR_FROM_THIS VIR_FROM_LIBXL
@@ -292,7 +293,7 @@ libxlMakeChrdevStr(virDomainChrDefPtr def, char **buf)
 
 static int
 libxlMakeDomBuildInfo(virDomainDefPtr def,
-                      libxl_ctx *ctx,
+                      libxlDriverConfigPtr cfg,
                       libxl_domain_config *d_config)
 {
     libxl_domain_build_info *b_info = &d_config->b_info;
@@ -308,7 +309,7 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
         libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_PV);
 
     b_info->max_vcpus = virDomainDefGetVcpusMax(def);
-    if (libxl_cpu_bitmap_alloc(ctx, &b_info->avail_vcpus, b_info->max_vcpus))
+    if (libxl_cpu_bitmap_alloc(cfg->ctx, &b_info->avail_vcpus, b_info->max_vcpus))
         return -1;
     libxl_bitmap_set_none(&b_info->avail_vcpus);
     for (i = 0; i < virDomainDefGetVcpus(def); i++)
@@ -374,6 +375,42 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
                           def->features[VIR_DOMAIN_FEATURE_ACPI] ==
                           VIR_TRISTATE_SWITCH_ON);
 
+        if (cfg && def->cpu &&
+                   def->cpu->mode == (VIR_CPU_MODE_HOST_PASSTHROUGH)) {
+            bool hasHwVirt = false;
+            bool svm = false, vmx = false;
+            virCapsPtr caps = cfg->caps;
+
+            if (caps && ARCH_IS_X86(def->os.arch)) {
+                virCPUDefPtr cpuDef = caps->host.cpu;
+
+                vmx = virCPUCheckFeature(
+                        cfg->caps->host.arch, cpuDef, "vmx");
+                svm = virCPUCheckFeature(
+                        cfg->caps->host.arch, cpuDef, "svm");
+                hasHwVirt = (vmx | svm);
+            }
+
+            if (def->cpu->nfeatures) {
+                for (i = 0; i < def->cpu->nfeatures; i++) {
+
+                    switch (def->cpu->features[i].policy) {
+
+                        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")))
+                                hasHwVirt = false;
+                            break;
+
+                        default:
+                            break;
+                    }
+                }
+            }
+            libxl_defbool_set(&b_info->u.hvm.nested_hvm, hasHwVirt);
+        }
+
         if (def->nsounds > 0) {
             /*
              * Use first sound device.  man xl.cfg(5) describes soundhw as
@@ -2087,15 +2124,15 @@ int
 libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
                        virDomainDefPtr def,
                        const char *channelDir LIBXL_ATTR_UNUSED,
-                       libxl_ctx *ctx,
+                       libxlDriverConfigPtr cfg,
                        libxl_domain_config *d_config)
 {
     libxl_domain_config_init(d_config);
 
-    if (libxlMakeDomCreateInfo(ctx, def, &d_config->c_info) < 0)
+    if (libxlMakeDomCreateInfo(cfg->ctx, def, &d_config->c_info) < 0)
         return -1;
 
-    if (libxlMakeDomBuildInfo(def, ctx, d_config) < 0)
+    if (libxlMakeDomBuildInfo(def, cfg, d_config) < 0)
         return -1;
 
     if (libxlMakeDiskList(def, d_config) < 0)
diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h
index c653c9f..7a83669 100644
--- a/src/libxl/libxl_conf.h
+++ b/src/libxl/libxl_conf.h
@@ -216,7 +216,7 @@ int
 libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
                        virDomainDefPtr def,
                        const char *channelDir LIBXL_ATTR_UNUSED,
-                       libxl_ctx *ctx,
+                       libxlDriverConfigPtr cfg,
                        libxl_domain_config *d_config);
 
 static inline void
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 57ec661..562bc67 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -1256,7 +1256,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
         goto cleanup_dom;
 
     if (libxlBuildDomainConfig(driver->reservedGraphicsPorts, vm->def,
-                               cfg->channelDir, cfg->ctx, &d_config) < 0)
+                               cfg->channelDir, cfg, &d_config) < 0)
         goto cleanup_dom;
 
     if (cfg->autoballoon && libxlDomainFreeMem(cfg->ctx, &d_config) < 0)
-- 
2.9.3