[libvirt] [PATCH 07/10] libxl: add support for PVH
Marek Marczykowski-Górecki
marmarek at invisiblethingslab.com
Tue Sep 11 01:10:43 UTC 2018
On Mon, Sep 10, 2018 at 04:45:50PM -0600, Jim Fehlig wrote:
> On 09/10/2018 04:02 PM, Marek Marczykowski-Górecki wrote:
> > On Mon, Sep 10, 2018 at 03:44:33PM -0600, Jim Fehlig wrote:
> > > On 08/05/2018 03:48 PM, Marek Marczykowski-Górecki wrote:
> > > > Since this is something between PV and HVM, it makes sense to put the
> > > > setting in place where domain type is specified.
> > > > To enable it, use <os><type machine="xenpvh">...</type></os>. It is
> > > > also included in capabilities.xml, for every supported HVM guest type - it
> > > > doesn't seems to be any other requirement (besides new enough Xen).
> > > >
> > > > Signed-off-by: Marek Marczykowski-Górecki <marmarek at invisiblethingslab.com>
> > > > ---
> > > > docs/formatcaps.html.in | 4 +--
> > > > docs/schemas/domaincommon.rng | 1 +-
> > > > src/libxl/libxl_capabilities.c | 23 ++++++++++++++++++--
> > > > src/libxl/libxl_conf.c | 41 ++++++++++++++++++++++++++++++-----
> > > > src/libxl/libxl_driver.c | 6 +++--
> > > > 5 files changed, 64 insertions(+), 11 deletions(-)
> > > >
> > > > diff --git a/docs/formatcaps.html.in b/docs/formatcaps.html.in
> > > > index 34a74a9..1f17aa9 100644
> > > > --- a/docs/formatcaps.html.in
> > > > +++ b/docs/formatcaps.html.in
> > > > @@ -104,8 +104,8 @@
> > > > <dt><code>machine</code></dt><dd>Machine type, for use in
> > > > <a href="formatdomain.html#attributeOSTypeMachine">machine</a>
> > > > attribute of os/type element in domain XML. For example Xen
> > > > - supports <code>xenfv</code> for HVM or <code>xenpv</code> for
> > > > - PV.</dd>
> > > > + supports <code>xenfv</code> for HVM, <code>xenpv</code> for
> > > > + PV, or <code>xenpvh</code> for PVHv2.</dd>
> > > > <dt><code>domain</code></dt><dd>Supported domain type, named by the
> > > > <code>type</code> attribute.</dd>
> > > > </dl>
> > > > diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> > > > index eded1ca..d32b0cb 100644
> > > > --- a/docs/schemas/domaincommon.rng
> > > > +++ b/docs/schemas/domaincommon.rng
> > > > @@ -341,6 +341,7 @@
> > > > <choice>
> > > > <value>xenpv</value>
> > > > <value>xenfv</value>
> > > > + <value>xenpvh</value>
> > > > </choice>
> > > > </attribute>
> > > > </optional>
> > > > diff --git a/src/libxl/libxl_capabilities.c b/src/libxl/libxl_capabilities.c
> > > > index 18596c7..e7b26f1 100644
> > > > --- a/src/libxl/libxl_capabilities.c
> > > > +++ b/src/libxl/libxl_capabilities.c
> > > > @@ -57,6 +57,7 @@ struct guest_arch {
> > > > virArch arch;
> > > > int bits;
> > > > int hvm;
> > > > + int pvh;
> > > > int pae;
> > > > int nonpae;
> > > > int ia64_be;
> > > > @@ -491,13 +492,29 @@ libxlCapsInitGuests(libxl_ctx *ctx, virCapsPtr caps)
> > > > guest_archs[i].nonpae = nonpae;
> > > > if (ia64_be)
> > > > guest_archs[i].ia64_be = ia64_be;
> > > > +
> > > > + /* On Xen >= 4.9 add PVH for each HVM guest, and do it only once */
> > >
> > > I'm having problems understanding this. Do you mean add a PVH for each
> > > supported HVM arch, but exclude PAE? E.g. standard xen_caps on x86_64
> > > contains
> > >
> > > xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
> > >
> > > Given these caps, should a PVH be added that corresponds to the
> > > hvm-3.0-x86_32 cap and another for the hvm-3.0-x86_64 cap, but the
> > > hvm-3.0-x86_32p cap excluded?
> >
> > Yes, exactly. Setting PAE (or not) is possible only for HVM, but not
> > PVH.
> >
> > It would be much better if Xen would report support for PVH
> > explicitly...
> >
> > > > + if ((ver_info->xen_version_major > 4 ||
> > > > + (ver_info->xen_version_major == 4 &&
> > > > + ver_info->xen_version_minor >= 9)) &&
> > > > + hvm && i == nr_guest_archs-1) {
>
> How about checking for hvm && !pae instead of i == nr_guest_archs-1?
At this time it should be ok. The i == nr_guest_archs-1 is based
directly on
if (i == nr_guest_archs)
nr_guest_archs++
earlier up. So, it is indeed added only when given arch was added to
guest_archs, regardless of what conditions were used for that.
Maybe, use something like this instead:
bool new_arch_added;
if ((new_arch_added = (i == nr_guest_archs)))
nr_guest_archs++
...
if (... hvm && new_arch_added)
?
>
> > > > + i = nr_guest_archs;
> > > > + /* Too many arch flavours - highly unlikely ! */
> > > > + if (i >= ARRAY_CARDINALITY(guest_archs))
> > > > + continue;
> > > > + nr_guest_archs++;
> > > > + guest_archs[i].arch = arch;
> > > > + guest_archs[i].pvh = 1;
> > > > + }
> > >
> > > Without answers to the above questions, I can't really comment on this code.
> > > Regardless, since PVH is not advertised in xen_caps shouldn't it be added to
> > > guest_archs outside of the loop parsing xen_caps?
> >
> > This works on assumption that if you have HVM and new enough Xen, then
> > you have PVH. Just having new Xen isn't enough - for example the
> > hardware may lack VT-x.
> >
> > > > }
> > > > }
> > > > regfree(®ex);
> > > > for (i = 0; i < nr_guest_archs; ++i) {
> > > > virCapsGuestPtr guest;
> > > > - char const *const xen_machines[] = {guest_archs[i].hvm ? "xenfv" : "xenpv"};
> > > > + char const *const xen_machines[] = {
> > > > + guest_archs[i].hvm ? "xenfv" :
> > > > + (guest_archs[i].pvh ? "xenpvh" : "xenpv")};
> > > > virCapsGuestMachinePtr *machines;
> > > > if ((machines = virCapabilitiesAllocMachines(xen_machines, 1)) == NULL)
> > > > @@ -557,7 +574,9 @@ libxlCapsInitGuests(libxl_ctx *ctx, virCapsPtr caps)
> > > > 1,
> > > > 0) == NULL)
> > > > return -1;
> > > > + }
> > > > + if (guest_archs[i].hvm || guest_archs[i].pvh) {
> > > > if (virCapabilitiesAddGuestFeature(guest,
> > > > "hap",
> > > > 1,
> > > > @@ -580,7 +599,7 @@ libxlMakeDomainOSCaps(const char *machine,
> > > > os->supported = true;
> > > > - if (STREQ(machine, "xenpv"))
> > > > + if (STREQ(machine, "xenpv") || STREQ(machine, "xenpvh"))
> > > > return 0;
> > > > capsLoader->supported = true;
> > > > diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> > > > index f3da0ed..2df40ec 100644
> > > > --- a/src/libxl/libxl_conf.c
> > > > +++ b/src/libxl/libxl_conf.c
> > > > @@ -133,8 +133,11 @@ libxlMakeDomCreateInfo(libxl_ctx *ctx,
> > > > libxl_domain_create_info_init(c_info);
> > > > - if (def->os.type == VIR_DOMAIN_OSTYPE_HVM) {
> > > > - c_info->type = LIBXL_DOMAIN_TYPE_HVM;
> > > > + if (def->os.type == VIR_DOMAIN_OSTYPE_HVM ||
> > > > + (def->os.type == VIR_DOMAIN_OSTYPE_XEN &&
> > > > + STREQ(def->os.machine, "xenpvh"))) {
> > > > + c_info->type = def->os.type == VIR_DOMAIN_OSTYPE_HVM ?
> > > > + LIBXL_DOMAIN_TYPE_HVM : LIBXL_DOMAIN_TYPE_PVH;
> > > > switch ((virTristateSwitch) def->features[VIR_DOMAIN_FEATURE_HAP]) {
> > > > case VIR_TRISTATE_SWITCH_OFF:
> > > > libxl_defbool_set(&c_info->hap, false);
> > > > @@ -276,7 +279,8 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
> > > > virDomainClockDef clock = def->clock;
> > > > libxl_ctx *ctx = cfg->ctx;
> > > > libxl_domain_build_info *b_info = &d_config->b_info;
> > > > - int hvm = def->os.type == VIR_DOMAIN_OSTYPE_HVM;
> > > > + bool hvm = def->os.type == VIR_DOMAIN_OSTYPE_HVM;
> > > > + bool pvh = STREQ(def->os.machine, "xenpvh");
> > > > size_t i;
> > > > size_t nusbdevice = 0;
> > > > @@ -284,6 +288,8 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
> > > > if (hvm)
> > > > libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_HVM);
> > > > + else if (pvh)
> > > > + libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_PVH);
> > > > else
> > > > libxl_domain_build_info_init_type(b_info, LIBXL_DOMAIN_TYPE_PV);
> > > > @@ -375,7 +381,7 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
> > > > def->mem.cur_balloon = VIR_ROUND_UP(def->mem.cur_balloon, 1024);
> > > > b_info->max_memkb = virDomainDefGetMemoryInitial(def);
> > > > b_info->target_memkb = def->mem.cur_balloon;
> > > > - if (hvm) {
> > > > + if (hvm || pvh) {
> > > > if (caps &&
> > > > def->cpu && def->cpu->mode == (VIR_CPU_MODE_HOST_PASSTHROUGH)) {
> > > > bool hasHwVirt = false;
> > > > @@ -647,6 +653,31 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
> > > > return -1;
> > > > }
> > > > #endif
> > > > + } else if (pvh) {
> > > > +#ifdef LIBXL_HAVE_BUILDINFO_KERNEL
> > > > + if (VIR_STRDUP(b_info->cmdline, def->os.cmdline) < 0)
> > > > + return -1;
> > > > + if (VIR_STRDUP(b_info->kernel, def->os.kernel) < 0)
> > > > + return -1;
> > > > + if (VIR_STRDUP(b_info->ramdisk, def->os.initrd) < 0)
> > > > + return -1;
> > > > +#else
> > > > + /*
> > > > + * Shouldn't happen as LIBXL_HAVE_BUILDINFO_KERNEL is there since Xen
> > > > + * 4.5, but PVHv2 since 4.9.
> > > > + */
> > > > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> > > > + _("PVH guest type not supported"));
> > > > +#endif
> > >
> > > I guess this is needed else the build will fail on Xen < 4.5?
> >
> > Yes, exactly.
> >
> > > Maybe it is
> > > time to bump the minimum supported Xen version to 4.6 :-). I say that a bit
> > > jokingly, but I did propose it a few months back.
> >
> > IMO good idea, since Xen < 4.6 is not supported anymore.
>
> BTW, here is a link to my earlier series to drop support for 4.4 and 4.5
>
> https://www.redhat.com/archives/libvir-list/2018-March/msg01704.html
>
> I'll rebase and resend that soon.
>
> Regards,
> Jim
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20180911/9bc75dc1/attachment-0001.sig>
More information about the libvir-list
mailing list