[libvirt] [PATCH RESEND v5] Export KVM Host Power Management capabilities
Daniel Veillard
veillard at redhat.com
Tue Nov 22 03:29:41 UTC 2011
On Wed, Nov 09, 2011 at 04:38:02PM +0530, Srivatsa S. Bhat wrote:
> This patch exports KVM Host Power Management capabilities as XML so that
> higher-level systems management software can make use of these features
> available in the host.
>
> The script "pm-is-supported" (from pm-utils package) is run to discover if
> Suspend-to-RAM (S3) or Suspend-to-Disk (S4) is supported by the host.
> If either of them are supported, then a new tag "<power_management>" is
> introduced in the XML under the <host> tag.
>
> Eg: When the host supports both S3 and S4, the XML looks like this:
>
> <capabilities>
>
> <host>
> <uuid>dc699581-48a2-11cb-b8a8-9a0265a79bbe</uuid>
> <cpu>
> <arch>i686</arch>
> <model>coreduo</model>
> <vendor>Intel</vendor>
> <topology sockets='1' cores='2' threads='1'/>
> <feature name='xtpr'/>
> <feature name='tm2'/>
> <feature name='est'/>
> <feature name='vmx'/>
> <feature name='pbe'/>
> <feature name='tm'/>
> <feature name='ht'/>
> <feature name='ss'/>
> <feature name='acpi'/>
> <feature name='ds'/>
> </cpu>
> <power_management> <<<=== New host power management features
> <S3/>
> <S4/>
> </power_management>
> <migration_features>
> <live/>
> <uri_transports>
> <uri_transport>tcp</uri_transport>
> </uri_transports>
> </migration_features>
> </host>
> .
> .
> .
>
> However in case the query to check for power management features succeeded,
> but the host does not support any such feature, then the XML will contain
> an empty <power_management/> tag. In the event that the PM query itself
> failed, the XML will not contain any "power_management" tag.
>
> To use this, new APIs could be implemented in libvirt to exploit power
> management features such as S3/S4. This was discussed in [1] and [2].
>
> Changelog:
> ---------
> This version v5:
> Some redundant error messages were removed and the code was streamlined.
>
> v4: http://www.redhat.com/archives/libvir-list/2011-August/msg00316.html
> v3: http://www.redhat.com/archives/libvir-list/2011-August/msg00282.html
> v2: http://www.redhat.com/archives/libvir-list/2011-August/msg00238.html
> v1: http://thread.gmane.org/gmane.comp.emulators.libvirt/40886
>
> References:
> ----------
> [1] http://www.redhat.com/archives/libvir-list/2011-August/msg00248.html
> [2] http://www.redhat.com/archives/libvir-list/2011-August/msg00302.html
>
> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>
[...]
> index 0a63a1c..eac1d02 100644
> --- a/docs/schemas/capability.rng
> +++ b/docs/schemas/capability.rng
> @@ -35,6 +35,9 @@
> </optional>
> </element>
> <optional>
> + <ref name='power_management'/>
> + </optional>
> + <optional>
> <ref name='migration'/>
> </optional>
> <optional>
> @@ -105,6 +108,21 @@
> </zeroOrMore>
> </define>
>
> + <define name='power_management'>
> + <element name='power_management'>
Seems to me you don't care about S3 and S4 order so
<interleave>
> + <optional>
> + <element name='S3'>
> + <empty/>
> + </element>
> + </optional>
> + <optional>
> + <element name='S4'>
> + <empty/>
> + </element>
> + </optional>
</interleave>
should be added, but that's minor.
> + </element>
> + </define>
> +
[...]
> diff --git a/libvirt.spec.in b/libvirt.spec.in
> index c74b0ea..23487e3 100644
> --- a/libvirt.spec.in
> +++ b/libvirt.spec.in
> @@ -493,6 +493,8 @@ Requires: nc
> Requires: gettext
> # Needed by virt-pki-validate script.
> Requires: gnutls-utils
> +# Needed for probing the power management features of the host.
> +Requires: pm-utils
Okay that seems present even on RHEL-5
> %if %{with_sasl}
> Requires: cyrus-sasl
> # Not technically required, but makes 'out-of-box' config
> diff --git a/src/conf/capabilities.c b/src/conf/capabilities.c
> index 40e2976..87b60b0 100644
> --- a/src/conf/capabilities.c
> +++ b/src/conf/capabilities.c
> @@ -29,6 +29,13 @@
> #include "util.h"
> #include "uuid.h"
> #include "cpu_conf.h"
> +#include "virterror_internal.h"
> +
> +
> +#define VIR_FROM_THIS VIR_FROM_CAPABILITIES
> +
> +VIR_ENUM_IMPL(virHostPMCapability, VIR_HOST_PM_LAST,
> + "S3", "S4")
>
> /**
> * virCapabilitiesNew:
> @@ -201,7 +208,6 @@ virCapabilitiesAddHostFeature(virCapsPtr caps,
> return 0;
> }
>
> -
> /**
> * virCapabilitiesAddHostMigrateTransport:
> * @caps: capabilities to extend
> @@ -687,6 +693,25 @@ virCapabilitiesFormatXML(virCapsPtr caps)
>
> virBufferAddLit(&xml, " </cpu>\n");
>
> + if (caps->host.powerMgmt_valid) {
> + /* The PM query was successful. */
> + if (caps->host.powerMgmt) {
> + /* The host supports some PM features. */
> + unsigned int pm = caps->host.powerMgmt;
> + virBufferAddLit(&xml, " <power_management>\n");
> + while (pm) {
> + int bit = ffs(pm) - 1;
> + virBufferAsprintf(&xml, " <%s/>\n",
> + virHostPMCapabilityTypeToString(bit));
> + pm &= ~(1U << bit);
> + }
> + virBufferAddLit(&xml, " </power_management>\n");
> + } else {
> + /* The host does not support any PM feature. */
> + virBufferAddLit(&xml, " <power_management/>\n");
> + }
> + }
> +
> if (caps->host.offlineMigrate) {
> virBufferAddLit(&xml, " <migration_features>\n");
> if (caps->host.liveMigrate)
> diff --git a/src/conf/capabilities.h b/src/conf/capabilities.h
> index dd4a827..148c7cc 100644
> --- a/src/conf/capabilities.h
> +++ b/src/conf/capabilities.h
> @@ -105,6 +105,10 @@ struct _virCapsHost {
> size_t nfeatures;
> size_t nfeatures_max;
> char **features;
> + bool powerMgmt_valid;
> + unsigned int powerMgmt; /* Bitmask of the PM capabilities.
> + * See enum virHostPMCapability.
> + */
> int offlineMigrate;
> int liveMigrate;
> size_t nmigrateTrans;
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 6a1562e..4d366d4 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1128,6 +1128,7 @@ virFormatMacAddr;
> virGenerateMacAddr;
> virGetGroupID;
> virGetHostname;
> +virGetPMCapabilities;
> virGetUserDirectory;
> virGetUserID;
> virGetUserName;
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 26a7f11..e1cc760 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -848,6 +848,13 @@ virCapsPtr qemuCapsInit(virCapsPtr old_caps)
> old_caps->host.cpu = NULL;
> }
>
> + /* Add the power management features of the host */
> +
> + if (virGetPMCapabilities(&caps->host.powerMgmt) < 0)
> + VIR_WARN("Failed to get host power management capabilities");
> + else
> + caps->host.powerMgmt_valid = true; /* The PM query succeeded. */
> +
> virCapabilitiesAddHostMigrateTransport(caps,
> "tcp");
I would probably explicitely set caps->host.powerMgmt_valid to false
if that failed instead of relying on "false" being 0 ...
> diff --git a/src/util/util.c b/src/util/util.c
> index 959c224..6f0f84a 100644
> --- a/src/util/util.c
> +++ b/src/util/util.c
> @@ -2607,3 +2607,54 @@ or other application using the libvirt API.\n\
>
> return 0;
> }
> +
> +/**
> + * Get the Power Management Capabilities of the host system.
> + * The script 'pm-is-supported' (from the pm-utils package) is run
> + * to find out all the power management features supported by the host,
> + * such as Suspend-to-RAM (S3) and Suspend-to-Disk (S4).
> + *
> + * @bitmask: Pointer to the bitmask which will be set appropriately to
> + * indicate all the supported host power management features.
> + *
> + * Returns 0 if the query was successful, -1 upon failure.
> + */
> +int
> +virGetPMCapabilities(unsigned int *bitmask)
> +{
> + int ret = -1;
> + int status;
> + virCommandPtr cmd;
> +
> + *bitmask = 0;
> +
> + /* Check support for Suspend-to-RAM (S3) */
> + cmd = virCommandNewArgList("pm-is-supported", "--suspend", NULL);
> + if (virCommandRun(cmd, &status) < 0)
> + goto cleanup;
> +
> + /* Check return code of command == 0 for success
> + * (i.e., the PM capability is supported)
> + */
> + if (status == 0)
> + *bitmask |= 1U << VIR_HOST_PM_S3;
> + virCommandFree(cmd);
> +
> + /* Check support for Suspend-to-Disk (S4) */
> + cmd = virCommandNewArgList("pm-is-supported", "--hibernate", NULL);
> + if (virCommandRun(cmd, &status) < 0)
> + goto cleanup;
> +
> + /* Check return code of command == 0 for success
> + * (i.e., the PM capability is supported)
> + */
> + if (status == 0)
> + *bitmask |= 1U << VIR_HOST_PM_S4;
> +
> + ret = 0;
> +
> +cleanup:
> + virCommandFree(cmd);
> + return ret;
> +}
> +
> diff --git a/src/util/util.h b/src/util/util.h
> index d8176a8..b1c4847 100644
> --- a/src/util/util.h
> +++ b/src/util/util.h
> @@ -258,4 +258,18 @@ bool virIsDevMapperDevice(const char *dev_name) ATTRIBUTE_NONNULL(1);
> int virEmitXMLWarning(int fd,
> const char *name,
> const char *cmd) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
> +
> +/* Power Management Capabilities of the host system */
> +
> +enum virHostPMCapability {
> + VIR_HOST_PM_S3, /* Suspend-to-RAM */
> + VIR_HOST_PM_S4, /* Suspend-to-Disk */
> +
> + VIR_HOST_PM_LAST
> +};
> +
> +VIR_ENUM_DECL(virHostPMCapability)
> +
> +int virGetPMCapabilities(unsigned int *);
> +
> #endif /* __VIR_UTIL_H__ */
> diff --git a/src/util/virterror.c b/src/util/virterror.c
> index 5006fa2..44a276a 100644
> --- a/src/util/virterror.c
> +++ b/src/util/virterror.c
> @@ -175,6 +175,9 @@ static const char *virErrorDomainName(virErrorDomain domain) {
> case VIR_FROM_HYPERV:
> dom = "Hyper-V ";
> break;
> + case VIR_FROM_CAPABILITIES:
> + dom = "Capabilities ";
> + break;
> }
> return(dom);
> }
ACK, I made the couple of modifications above, cleaned up "make syntax-check"
and fixed a small issue in applying the patch to util.h, then commited
it,
thanks a lot !
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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