[RFC PATCH 1/2] Add support for specifying max physical address size.
Dario Faggioli
dfaggioli at suse.com
Thu Oct 29 15:55:36 UTC 2020
This patch introduces the:
<maxphysaddr mode='passthrough'/>
<maxphysaddr mode='emulate' bits='42'/>
sub element of /domain/cpu.
Purpose is being able to have a guest see the physical address size
exactly as the host does (if mode='passthrough' is used) or any size
the user wants it to see (if mode='emulate' is used and bits='' is
specified).
This can be useful if the VM needs to have a large amount of memory.
Signed-off-by: Dario Faggioli <dfaggioli at suse.com>
---
docs/formatdomain.rst | 21 ++++++++
docs/schemas/cputypes.rng | 19 +++++++
src/conf/cpu_conf.c | 52 ++++++++++++++++++++
src/conf/cpu_conf.h | 17 +++++++
src/libvirt_private.syms | 2 +
.../genericxml2xmlindata/cpu-phys-bits-emulate.xml | 20 ++++++++
.../cpu-phys-bits-passthrough.xml | 20 ++++++++
tests/genericxml2xmltest.c | 3 +
8 files changed, 154 insertions(+)
create mode 100644 tests/genericxml2xmlindata/cpu-phys-bits-emulate.xml
create mode 100644 tests/genericxml2xmlindata/cpu-phys-bits-passthrough.xml
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index ae635bedff..851391011f 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1207,6 +1207,7 @@ following collection of elements. :since:`Since 0.7.5`
<vendor>Intel</vendor>
<topology sockets='1' dies='1' cores='2' threads='1'/>
<cache level='3' mode='emulate'/>
+ <maxphysaddr mode='emulate' bits='42'>
<feature policy='disable' name='lahf_lm'/>
</cpu>
...
@@ -1223,6 +1224,7 @@ following collection of elements. :since:`Since 0.7.5`
<cpu mode='host-passthrough' migratable='off'>
<cache mode='passthrough'/>
+ <maxphysaddr mode='passthrough'>
<feature policy='disable' name='lahf_lm'/>
...
@@ -1446,6 +1448,25 @@ In case no restrictions need to be put on CPU model and its features, a simpler
The virtual CPU will report no CPU cache of the specified level (or no
cache at all if the ``level`` attribute is missing).
+``maxphysaddress``
+ :since:`Since 6.10.0` the ``maxphysaddr`` element specifies the size in bits
+ of the physical addresses. The default behavior is that the vCPUs will see
+ what it is configured by default in the hypervisor itself.
+
+ ``mode``
+ The following values are supported:
+
+ ``passthrough``
+ The number of physical address bits reported by the host CPU will be
+ passed through to the virtual CPUs
+ ``emulate``
+ The hypervisor will define a specific value for the number of bits
+ of physical addresses via the ``bits`` arrtibute, which is mandatory.
+
+ ``bits``
+ The number of bits of the physical addresses that the vCPUs should see,
+ if the ``mode`` attribute is set to ``emulate``.
+
Guest NUMA topology can be specified using the ``numa`` element. :since:`Since
0.9.8`
diff --git a/docs/schemas/cputypes.rng b/docs/schemas/cputypes.rng
index aea6ff0267..232115226a 100644
--- a/docs/schemas/cputypes.rng
+++ b/docs/schemas/cputypes.rng
@@ -299,6 +299,22 @@
</element>
</define>
+ <define name="cpuMaxPhysAddr">
+ <element name="maxphysaddr">
+ <attribute name="mode">
+ <choice>
+ <value>emulate</value>
+ <value>passthrough</value>
+ </choice>
+ </attribute>
+ <optional>
+ <attribute name="bits">
+ <ref name="unsignedInt"/>
+ </attribute>
+ </optional>
+ </element>
+ </define>
+
<define name="hostcpu">
<element name="cpu">
<element name="arch">
@@ -410,6 +426,9 @@
<optional>
<ref name="cpuCache"/>
</optional>
+ <optional>
+ <ref name="cpuMaxPhysAddr"/>
+ </optional>
</interleave>
</element>
</define>
diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c
index 7778e01131..a151bbf45b 100644
--- a/src/conf/cpu_conf.c
+++ b/src/conf/cpu_conf.c
@@ -83,6 +83,11 @@ VIR_ENUM_IMPL(virCPUCacheMode,
"disable",
);
+VIR_ENUM_IMPL(virCPUMaxPhysAddrMode,
+ VIR_CPU_MAX_PHYS_ADDR_MODE_LAST,
+ "emulate",
+ "passthrough",
+);
virCPUDefPtr virCPUDefNew(void)
{
@@ -128,6 +133,7 @@ virCPUDefFree(virCPUDefPtr def)
if (g_atomic_int_dec_and_test(&def->refs)) {
virCPUDefFreeModel(def);
VIR_FREE(def->cache);
+ VIR_FREE(def->addr);
VIR_FREE(def->tsc);
VIR_FREE(def);
}
@@ -250,6 +256,11 @@ virCPUDefCopyWithoutModel(const virCPUDef *cpu)
*copy->cache = *cpu->cache;
}
+ if (cpu->addr) {
+ copy->addr = g_new0(virCPUMaxPhysAddrDef, 1);
+ *copy->addr = *cpu->addr;
+ }
+
if (cpu->tsc) {
copy->tsc = g_new0(virHostCPUTscInfo, 1);
*copy->tsc = *cpu->tsc;
@@ -670,6 +681,38 @@ virCPUDefParseXML(xmlXPathContextPtr ctxt,
def->cache->mode = mode;
}
+ if (virXPathInt("count(./maxphysaddr)", ctxt, &n) < 0) {
+ return -1;
+ } else if (n > 1) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("at most one CPU maximum physical address bits "
+ "element may be specified"));
+ return -1;
+ } else if (n == 1) {
+ int bits = -1;
+ g_autofree char *strmode = NULL;
+ int mode;
+
+ if (virXPathBoolean("boolean(./maxphysaddr[1]/@bits)", ctxt) == 1 &&
+ (virXPathInt("string(./maxphysaddr[1]/@bits)", ctxt, &bits) < 0 ||
+ bits < 0)) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("CPU maximum physical address bits < 0"));
+ return -1;
+ }
+
+ if (!(strmode = virXPathString("string(./maxphysaddr[1]/@mode)", ctxt)) ||
+ (mode = virCPUMaxPhysAddrModeTypeFromString(strmode)) < 0) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("missing or invalid CPU maximum physical "
+ "address bits mode"));
+ return -1;
+ }
+
+ def->addr = g_new0(virCPUMaxPhysAddrDef, 1);
+ def->addr->bits = bits;
+ def->addr->mode = mode;
+ }
*cpu = g_steal_pointer(&def);
return 0;
}
@@ -841,6 +884,15 @@ virCPUDefFormatBuf(virBufferPtr buf,
virBufferAddLit(buf, "/>\n");
}
+ if (def->addr) {
+ virBufferAddLit(buf, "<maxphysaddr ");
+ if (def->addr->bits != -1)
+ virBufferAsprintf(buf, "bits='%d' ", def->addr->bits);
+ virBufferAsprintf(buf, "mode='%s'",
+ virCPUMaxPhysAddrModeTypeToString(def->addr->mode));
+ virBufferAddLit(buf, "/>\n");
+ }
+
for (i = 0; i < def->nfeatures; i++) {
virCPUFeatureDefPtr feature = def->features + i;
diff --git a/src/conf/cpu_conf.h b/src/conf/cpu_conf.h
index 3ef14b7932..e7bbe916a3 100644
--- a/src/conf/cpu_conf.h
+++ b/src/conf/cpu_conf.h
@@ -117,6 +117,22 @@ struct _virCPUCacheDef {
virCPUCacheMode mode;
};
+typedef enum {
+ VIR_CPU_MAX_PHYS_ADDR_MODE_EMULATE,
+ VIR_CPU_MAX_PHYS_ADDR_MODE_PASSTHROUGH,
+
+ VIR_CPU_MAX_PHYS_ADDR_MODE_LAST
+} virCPUMaxPhysAddrMode;
+
+VIR_ENUM_DECL(virCPUMaxPhysAddrMode);
+
+typedef struct _virCPUMaxPhysAddrDef virCPUMaxPhysAddrDef;
+typedef virCPUMaxPhysAddrDef *virCPUMaxPhysAddrDefPtr;
+struct _virCPUMaxPhysAddrDef {
+ int bits; /* -1 for unspecified */
+ virCPUMaxPhysAddrMode mode;
+};
+
typedef struct _virCPUDef virCPUDef;
typedef virCPUDef *virCPUDefPtr;
@@ -140,6 +156,7 @@ struct _virCPUDef {
size_t nfeatures_max;
virCPUFeatureDefPtr features;
virCPUCacheDefPtr cache;
+ virCPUMaxPhysAddrDefPtr addr;
virHostCPUTscInfoPtr tsc;
virTristateSwitch migratable; /* for host-passthrough mode */
};
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 95e50835ad..8629f81d33 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -117,6 +117,8 @@ virCPUDefParseXMLString;
virCPUDefRef;
virCPUDefStealModel;
virCPUDefUpdateFeature;
+virCPUMaxPhysAddrModeTypeFromString;
+virCPUMaxPhysAddrModeTypeToString;
virCPUModeTypeToString;
diff --git a/tests/genericxml2xmlindata/cpu-phys-bits-emulate.xml b/tests/genericxml2xmlindata/cpu-phys-bits-emulate.xml
new file mode 100644
index 0000000000..0b1b0f1672
--- /dev/null
+++ b/tests/genericxml2xmlindata/cpu-phys-bits-emulate.xml
@@ -0,0 +1,20 @@
+<domain type='kvm'>
+ <name>foo</name>
+ <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+ <memory unit='KiB'>219136</memory>
+ <currentMemory unit='KiB'>219136</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='i686' machine='pc'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <cpu mode='host-passthrough'>
+ <maxphysaddr bits='42' mode='emulate'/>
+ </cpu>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ </devices>
+</domain>
diff --git a/tests/genericxml2xmlindata/cpu-phys-bits-passthrough.xml b/tests/genericxml2xmlindata/cpu-phys-bits-passthrough.xml
new file mode 100644
index 0000000000..cce676eaa6
--- /dev/null
+++ b/tests/genericxml2xmlindata/cpu-phys-bits-passthrough.xml
@@ -0,0 +1,20 @@
+<domain type='kvm'>
+ <name>foo</name>
+ <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+ <memory unit='KiB'>219136</memory>
+ <currentMemory unit='KiB'>219136</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='i686' machine='pc'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <cpu mode='host-passthrough'>
+ <maxphysaddr mode='passthrough'/>
+ </cpu>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ </devices>
+</domain>
diff --git a/tests/genericxml2xmltest.c b/tests/genericxml2xmltest.c
index 5110bfba86..6c1c6e699f 100644
--- a/tests/genericxml2xmltest.c
+++ b/tests/genericxml2xmltest.c
@@ -256,6 +256,9 @@ mymain(void)
DO_TEST_BACKUP_FULL("backup-pull-internal-invalid", true);
+ DO_TEST("cpu-phys-bits-emulate");
+ DO_TEST("cpu-phys-bits-passthrough");
+
virObjectUnref(caps);
virObjectUnref(xmlopt);
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