[libvirt] [PATCH v2 1/3] libxl: set nestedhvm for mode host-passthrough
Jim Fehlig
jfehlig at suse.com
Mon Apr 17 18:04:53 UTC 2017
On 03/24/2017 03:02 PM, 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.
>
> 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'/>
I think we should also give an example of enabling nested HVM. E.g.
<cpu mode='host-passthrough'/>
>
> 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;
I don't see much value in having this local variable.
> +
> + vmx = virCPUCheckFeature(
> + cfg->caps->host.arch, cpuDef, "vmx");
> + svm = virCPUCheckFeature(
> + cfg->caps->host.arch, cpuDef, "svm");
> + hasHwVirt = (vmx | svm);
> + }
And you already have a local 'caps' for cfg->caps. So this could be shortened a
bit to
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;
> +
> + default:
> + break;
Generally libvirt prefers to explicitly list all enum values in switch
statements, e.g.
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 +2124,15 @@ int
> libxlBuildDomainConfig(virPortAllocatorPtr graphicsports,
> virDomainDefPtr def,
> const char *channelDir LIBXL_ATTR_UNUSED,
> - libxl_ctx *ctx,
> + libxlDriverConfigPtr cfg,
> libxl_domain_config *d_config)
Long ago, in commits 5da28f24 and a6abdbf6, we changed this function signature
to make it easier to unit test. Unfortunately, the subsequent unit tests were
never ACKed and committed, but I haven't given up on that effort. Latest attempt
was sent to the list in February
https://www.redhat.com/archives/libvir-list/2017-February/msg01477.html
Looks like we just need cfg->caps in the call chain. Can we pass the virCapsPtr
to libxlBuildDomainConfig instead of the libxlDriverConfig object?
Regards,
Jim
> {
> 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)
>
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