On Mon, Aug 19, 2019 at 10:32:25AM +0200, Menno Lageman wrote:
From: Wim ten Have <wim.ten.have@xxxxxxxxxx>
QEMU introduced a CPU power management feature with commit 6f131f13e68d
("kvm: support -overcommit cpu-pm=on|off").
This patch series adds support for controlling QEMU's "-overcommit"
command line switch: "-overcommit cpu-pm=[on|off]". By default "cpu-pm" is off.
To turn the CPU power management feature on, the following
XML needs to be added to the guest's domain description:
<features>
<kvm>
<cpu-pm state='on'/>
</kvm>
</features>
Note that the "cpu-pm" element is only available if the CPU
mode is set to "host-passthrough":
<cpu mode='host-passthrough ... />
Signed-off-by: Wim ten Have <wim.ten.have@xxxxxxxxxx>
Signed-off-by: Menno Lageman <menno.lageman@xxxxxxxxxx>
---
docs/formatdomain.html.in | 7 +++++++
docs/schemas/domaincommon.rng | 5 +++++
src/conf/domain_conf.c | 4 ++++
src/conf/domain_conf.h | 1 +
src/libvirt_private.syms | 1 +
src/qemu/qemu_command.c | 16 +++++++++++++++-
src/qemu/qemu_domain.c | 25 ++++++++++++++++++-------
7 files changed, 51 insertions(+), 8 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index a18119f9a08e..7ea819ef6fb2 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -2045,6 +2045,7 @@
<kvm>
<hidden state='on'/>
<hint-dedicated state='on'/>
+ <cpu-pm state='on'/>
</kvm>
<pvspinlock state='on'/>
<gic version='2'/>
@@ -2224,6 +2225,12 @@
<td>on, off</td>
<td><span class="since">5.7.0 (QEMU 2.12.1)</span></td>
</tr>
Hmm, seems we did not bother to document hint-dedicated
+ <tr>
+ <td>cpu-pm</td>
+ <td>Enable guest management of the host CPU's power state. Note that enabling this will increase latency for other processes running on the same host CPU.</td>
+ <td>on, off</td>
+ <td><span class="since">5.7.0 (QEMU 2.12.1)</span></td>
+ </tr>
</table>
</dd>
<dt><code>pmu</code></dt>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 08853f9d9e92..51c9e434aa35 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -5970,6 +5970,11 @@
<ref name="featurestate"/>
</element>
</optional>
+ <optional>
+ <element name="cpu-pm">
+ <ref name="featurestate"/>
+ </element>
+ </optional>
</interleave>
</element>
</define>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 8642927d6bf3..e348aa0bcb5f 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -203,6 +203,7 @@ VIR_ENUM_IMPL(virDomainKVM,
VIR_DOMAIN_KVM_LAST,
"hidden",
"hint-dedicated",
+ "cpu-pm",
);
VIR_ENUM_IMPL(virDomainMsrsUnknown,
@@ -20412,6 +20413,7 @@ virDomainDefParseXML(xmlDocPtr xml,
switch ((virDomainKVM) feature) {
case VIR_DOMAIN_KVM_HIDDEN:
case VIR_DOMAIN_KVM_DEDICATED:
+ case VIR_DOMAIN_KVM_CPU_PM:
if (!(tmp = virXMLPropString(nodes[i], "state"))) {
virReportError(VIR_ERR_XML_ERROR,
_("missing 'state' attribute for "
@@ -22625,6 +22627,7 @@ virDomainDefFeaturesCheckABIStability(virDomainDefPtr src,
switch ((virDomainKVM) i) {
case VIR_DOMAIN_KVM_HIDDEN:
case VIR_DOMAIN_KVM_DEDICATED:
+ case VIR_DOMAIN_KVM_CPU_PM:
if (src->kvm_features[i] != dst->kvm_features[i]) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("State of KVM feature '%s' differs: "
@@ -28126,6 +28129,7 @@ virDomainDefFormatFeatures(virBufferPtr buf,
switch ((virDomainKVM) j) {
case VIR_DOMAIN_KVM_HIDDEN:
case VIR_DOMAIN_KVM_DEDICATED:
+ case VIR_DOMAIN_KVM_CPU_PM:
if (def->kvm_features[j])
virBufferAsprintf(&childBuf, "<%s state='%s'/>\n",
virDomainKVMTypeToString(j),
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index f7423b1b6f89..b5a4cee46c1e 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1766,6 +1766,7 @@ typedef enum {
typedef enum {
VIR_DOMAIN_KVM_HIDDEN = 0,
VIR_DOMAIN_KVM_DEDICATED,
+ VIR_DOMAIN_KVM_CPU_PM,
VIR_DOMAIN_KVM_LAST
} virDomainKVM;
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 9db4ac7933e5..67a3a14c9b36 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -446,6 +446,7 @@ virDomainIOThreadIDDel;
virDomainIOThreadIDFind;
virDomainKeyWrapCipherNameTypeFromString;
virDomainKeyWrapCipherNameTypeToString;
+virDomainKVMTypeToString;
virDomainLeaseDefFree;
virDomainLeaseIndex;
virDomainLeaseInsert;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 922456ec679e..163c98bc7d0f 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -7217,6 +7217,8 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
virBufferAddLit(&buf, ",kvm-hint-dedicated=on");
break;
+ /* Not a -cpu option */
+ case VIR_DOMAIN_KVM_CPU_PM:
/* coverity[dead_error_begin] */
case VIR_DOMAIN_KVM_LAST:
break;
@@ -7852,8 +7854,20 @@ qemuBuildOvercommitCommandLine(virCommandPtr cmd,
virQEMUCapsPtr qemuCaps)
{
if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_OVERCOMMIT)) {
+ virBuffer buf = VIR_BUFFER_INITIALIZER;
+ char *overcommit;
+
+ virBufferAsprintf(&buf, "mem-lock=%s", def->mem.locked ? "on" : "off");
+
+ if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON)
+ virBufferAsprintf(&buf, ",cpu-pm=%s",
+ def->kvm_features[VIR_DOMAIN_KVM_CPU_PM] == VIR_TRISTATE_SWITCH_ON ? "on" : "off");
const char *cpu_pm = NULL; if (def->kvm_features[VIR_DOMAIN_KVM_CPU_PM] != VIR_TRISTATE_SWITCH_DEFAULT) cpu_pm = virTristateBoolTypeToString(def->kvm_features[VIR_DOMAIN_KVM_CPU_PM]) if (cpu_pm) virBufferAsprintf... to avoid the super long line.
+
+ overcommit = virBufferContentAndReset(&buf);
virCommandAddArg(cmd, "-overcommit");
- virCommandAddArgFormat(cmd, "mem-lock=%s", def->mem.locked ? "on" : "off");
+ virCommandAddArgFormat(cmd, "%s", overcommit);
You can use virCommandAddArgBuffer and avoid the temporary char* variable
+
+ VIR_FREE(overcommit);
}
return 0;
}
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index a06672333cf7..5571f52fec47 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4442,7 +4442,7 @@ static int
qemuDomainDefValidateFeatures(const virDomainDef *def,
virQEMUCapsPtr qemuCaps)
{
- size_t i;
+ size_t i, j;
for (i = 0; i < VIR_DOMAIN_FEATURE_LAST; i++) {
const char *featureName = virDomainFeatureTypeToString(i);
@@ -4499,12 +4499,23 @@ qemuDomainDefValidateFeatures(const virDomainDef *def,
break;
case VIR_DOMAIN_FEATURE_KVM:
- if (def->kvm_features[VIR_DOMAIN_KVM_DEDICATED] == VIR_TRISTATE_SWITCH_ON &&
- (!def->cpu || def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH)) {
- virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
- _("kvm-hint-dedicated=on is only applicable "
- "for cpu host-passthrough"));
- return -1;
+ for (j = 0; j < VIR_DOMAIN_KVM_LAST; j++) {
+ switch ((virDomainKVM) j) {
+ case VIR_DOMAIN_KVM_DEDICATED:
+ case VIR_DOMAIN_KVM_CPU_PM:
+ if (def->kvm_features[j] == VIR_TRISTATE_SWITCH_ON &&
+ (!def->cpu || def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("%s=on is only applicable for cpu host-passthrough"),
+ virDomainKVMTypeToString(j));
+ return -1;
+ }
What if the user asks for cpu-pm but QEMU_CAPS_OVERCOMMIT is not available? Jano
+ break;
+
+ case VIR_DOMAIN_KVM_HIDDEN:
+ case VIR_DOMAIN_KVM_LAST:
+ break;
+ }
}
break;
--
2.21.0
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