[libvirt] [PATCH v3 1/3] libxl: set nestedhvm for mode host-passthrough

[Wim ten Have]

On Thu, 20 Apr 2017 14:28:11 -0600
Jim Fehlig <jfehlig at suse.com> wrote:

> Wim Ten Have wrote:
> > 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.
> > 
> > nested HVM is enabled by adding below on the target domain;
> > <cpu mode='host-passthrough'/>
> > 
> > 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   | 46 +++++++++++++++++++++++++++++++++++++++++-----
> >  src/libxl/libxl_conf.h   |  2 +-
> >  src/libxl/libxl_domain.c |  2 +-
> >  3 files changed, 43 insertions(+), 7 deletions(-)
> > 
> > diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> > index f5b788b..31508d6 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 +375,41 @@ 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)) {
> > +                vmx = virCPUCheckFeature(caps->host.arch, caps->host.cpu, "vmx");
> > +                svm = virCPUCheckFeature(caps->host.arch, caps->host.cpu, "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;
> > +
> > +                        case VIR_CPU_FEATURE_FORCE:
> > +                        case VIR_CPU_FEATURE_REQUIRE:
> > +                        case VIR_CPU_FEATURE_OPTIONAL:
> > +                        case VIR_CPU_FEATURE_LAST:
> > +                            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 +2123,15 @@ int
> >  libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
> >                         virDomainDefPtr def,
> >                         const char *channelDir LIBXL_ATTR_UNUSED,
> > -                       libxl_ctx *ctx,
> > +                       libxlDriverConfigPtr cfg,
> >                         libxl_domain_config *d_config)  
> 
> 
> I replied to your question about this function in the V2 thread. Essentially,
> I'd like to see this function changed to
> 
> libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
>                        virDomainDefPtr def,
>                        const char *channelDir LIBXL_ATTR_UNUSED,
>                        libxl_ctx *ctx,
>                        virCapsPtr caps,
>                        libxl_domain_config *d_config)
> 
> Looks good otherwise!

  Noticed!  And and changing signature adding caps as suggested is
  of course doable.  I'll prepare PATCH v4 and submit tomorrow.

Regards,
- Wim.