From: Hyman <huangy81@xxxxxxxxxxxxxxx>
QEMU introduced a dirty ring feature, this patch add a new
KVM feature 'dirty-ring' to set this feature for kvm guests.
To enable the feature, libvirt add "-accel dirty-gfn-count=xxx"
to QEMU command line, the following XML needs to be added to
the guest's domain description:
<features>
<kvm>
<dirty-ring state='on' size='xxx'>
</kvm>
</features>
Signed-off-by: Hyman <huangy81@xxxxxxxxxxxxxxx>
---
docs/formatdomain.rst | 16 +++++++++-------
docs/schemas/domaincommon.rng | 10 ++++++++++
src/conf/domain_conf.c | 34 ++++++++++++++++++++++++++++++++++
src/conf/domain_conf.h | 4 ++++
src/qemu/qemu_command.c | 13 ++++++++++---
5 files changed, 67 insertions(+), 10 deletions(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 6100b88e99..5bf8517cda 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1767,6 +1767,7 @@ Hypervisors may allow certain CPU / machine features to be toggled on/off.
<hidden state='on'/>
<hint-dedicated state='on'/>
<poll-control='on'/>
+ <dirty-ring state='on' size='4096'/>
</kvm>
<xen>
<e820_host state='on'/>
@@ -1849,13 +1850,14 @@ are:
``kvm``
Various features to change the behavior of the KVM hypervisor.
- ============== ============================================================================ ======= ============================
- Feature Description Value Since
- ============== ============================================================================ ======= ============================
- hidden Hide the KVM hypervisor from standard MSR based discovery on, off :since:`1.2.8 (QEMU 2.1.0)`
- hint-dedicated Allows a guest to enable optimizations when running on dedicated vCPUs on, off :since:`5.7.0 (QEMU 2.12.0)`
- poll-control Decrease IO completion latency by introducing a grace period of busy waiting on, off :since:`6.10.0 (QEMU 4.2)`
- ============== ============================================================================ ======= ============================
+ ============== ============================================================================ ================================== ============================
+ Feature Description Value Since
+ ============== ============================================================================ ================================== ============================
+ hidden Hide the KVM hypervisor from standard MSR based discovery on, off :since:`1.2.8 (QEMU 2.1.0)`
+ hint-dedicated Allows a guest to enable optimizations when running on dedicated vCPUs on, off :since:`5.7.0 (QEMU 2.12.0)`
+ poll-control Decrease IO completion latency by introducing a grace period of busy waiting on, off :since:`6.10.0 (QEMU 4.2)`
+ dirty-ring Enable dirty ring feature on, off; size - must be power of 2 :since:`7.0.0 (QEMU 5.2.1)`
+ ============== ============================================================================ ================================== ============================
``xen``
Various features to change the behavior of the Xen hypervisor.
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 7dc419bcc3..5af4bbeee6 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -6569,6 +6569,16 @@
<ref name="featurestate"/>
</element>
</optional>
+ <optional>
+ <element name="dirty-ring">
+ <ref name="featurestate"/>
+ <optional>
+ <attribute name="size">
+ <data type="unsignedInt"/>
+ </attribute>
+ </optional>
+ </element>
+ </optional>
</interleave>
</element>
</define>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 349fc28c2a..e617b952db 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -186,6 +186,7 @@ VIR_ENUM_IMPL(virDomainKVM,
"hidden",
"hint-dedicated",
"poll-control",
+ "dirty-ring",
);
VIR_ENUM_IMPL(virDomainXen,
@@ -18379,6 +18380,7 @@ virDomainFeaturesDefParse(virDomainDefPtr def,
if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) {
int feature;
int value;
+ node = ctxt->node;
if ((n = virXPathNodeSet("./features/kvm/*", ctxt, &nodes)) < 0)
return -1;
@@ -18395,6 +18397,7 @@ virDomainFeaturesDefParse(virDomainDefPtr def,
case VIR_DOMAIN_KVM_HIDDEN:
case VIR_DOMAIN_KVM_DEDICATED:
case VIR_DOMAIN_KVM_POLLCONTROL:
+ case VIR_DOMAIN_KVM_DIRTY_RING:
if (!(tmp = virXMLPropString(nodes[i], "state"))) {
virReportError(VIR_ERR_XML_ERROR,
_("missing 'state' attribute for "
@@ -18413,6 +18416,26 @@ virDomainFeaturesDefParse(virDomainDefPtr def,
VIR_FREE(tmp);
def->kvm_features[feature] = value;
+
+ /* only for dirty ring case */
+ if (((virDomainKVM) feature) == VIR_DOMAIN_KVM_DIRTY_RING &&
+ value == VIR_TRISTATE_SWITCH_ON) {
+ ctxt->node = nodes[i];
+ if (virXPathUInt("string(./@size)", ctxt,
+ &def->dirty_gfn_count) < 0) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("invalid number of dirty GFNs"));
+ return -1;
+ }
+
+ if ((def->dirty_gfn_count & (def->dirty_gfn_count - 1)) ||
+ def->dirty_gfn_count > 65536) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("max number of dirty GFNs is 65536 "
+ "and must be power of 2"));
+ return -1;
+ }
+ }
break;
/* coverity[dead_error_begin] */
@@ -18421,6 +18444,7 @@ virDomainFeaturesDefParse(virDomainDefPtr def,
}
}
VIR_FREE(nodes);
+ ctxt->node = node;
}
if (def->features[VIR_DOMAIN_FEATURE_XEN] == VIR_TRISTATE_SWITCH_ON) {
@@ -22521,6 +22545,7 @@ virDomainDefFeaturesCheckABIStability(virDomainDefPtr src,
case VIR_DOMAIN_KVM_HIDDEN:
case VIR_DOMAIN_KVM_DEDICATED:
case VIR_DOMAIN_KVM_POLLCONTROL:
+ case VIR_DOMAIN_KVM_DIRTY_RING:
if (src->kvm_features[i] != dst->kvm_features[i]) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("State of KVM feature '%s' differs: "
@@ -28271,6 +28296,15 @@ virDomainDefFormatFeatures(virBufferPtr buf,
def->kvm_features[j]));
break;
+ case VIR_DOMAIN_KVM_DIRTY_RING:
+ if (def->kvm_features[j])
+ virBufferAsprintf(&childBuf, "<%s state='%s' size='%d'/>\n",
+ virDomainKVMTypeToString(j),
+ virTristateSwitchTypeToString(
+ def->kvm_features[j]),
+ def->dirty_gfn_count);
+ break;
+
/* coverity[dead_error_begin] */
case VIR_DOMAIN_KVM_LAST:
break;
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index ec43bbe186..120d490ce7 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1917,6 +1917,7 @@ typedef enum {
VIR_DOMAIN_KVM_HIDDEN = 0,
VIR_DOMAIN_KVM_DEDICATED,
VIR_DOMAIN_KVM_POLLCONTROL,
+ VIR_DOMAIN_KVM_DIRTY_RING,
VIR_DOMAIN_KVM_LAST
} virDomainKVM;
@@ -2728,6 +2729,9 @@ struct _virDomainDef {
callbacks failed for a non-critical reason
(was not able to fill in some data) and thus
should be re-run before starting */
+
+ /* Number of dirty GFNs per ring */
+ unsigned int dirty_gfn_count;
};
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 0f660aaec3..31829baeea 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6525,6 +6525,9 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
virBufferAddLit(&buf, ",kvm-poll-control=on");
break;
+ case VIR_DOMAIN_KVM_DIRTY_RING:
+ break;
+
/* coverity[dead_error_begin] */
case VIR_DOMAIN_KVM_LAST:
break;
@@ -6959,9 +6962,13 @@ qemuBuildAccelCommandLineTcgOptions(void)
static void
-qemuBuildAccelCommandLineKvmOptions(void)
+qemuBuildAccelCommandLineKvmOptions(virBuffer *buf,
+ const virDomainDef *def)
{
- /* implemented in the next patch */
+ if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON &&
+ def->kvm_features[VIR_DOMAIN_KVM_DIRTY_RING] == VIR_TRISTATE_SWITCH_ON) {
+ virBufferAsprintf(buf, ",dirty-gfn-count=%d", def->dirty_gfn_count);
+ }
}
@@ -6982,7 +6989,7 @@ qemuBuildAccelCommandLine(virCommandPtr cmd,
case VIR_DOMAIN_VIRT_KVM:
virBufferAddLit(&buf, "kvm");
- qemuBuildAccelCommandLineKvmOptions();
+ qemuBuildAccelCommandLineKvmOptions(&buf, def);
break;
case VIR_DOMAIN_VIRT_KQEMU:
--
2.24.3
