>From c3572e59f1e56322ba92ab35e31da48dd63b7cec Mon Sep 17 00:00:00 2001
From: Prerna Saxena <prerna@xxxxxxxxxxxxxxxxxx>
Date: Tue, 21 Oct 2014 01:06:51 -0400
PowerISA allows processors to run VMs in binary compatibility ("compat")
mode supporting an older version of ISA. QEMU has recently added support to
explicitly denote a VM running in compatibility mode through commit 6d9412ea
& 8dfa3a5e85.
Now, a "compat" mode VM can be run by invoking this qemu commandline on a
POWER8 host: -cpu host,compat=power7.
This patch allows libvirt to extend the "fallback" semantics of cpu model to
describe this new mode for PowerKVM guests.
As an example:
When a user wants to request a power7 vm to run in compatibility mode on
a Power8 host, this can be described in XML as follows :
<cpu mode='host-model' match='exact'>
<model fallback='compat'>power7</model>
</cpu>
Signed-off-by: Prerna Saxena <prerna@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Li Zhang <zhlcindy@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Pradipta Kr. Banerjee <bpradip@xxxxxxxxxx>
---
docs/schemas/domaincommon.rng | 1 +
src/conf/cpu_conf.c | 4 +++-
src/conf/cpu_conf.h | 1 +
src/cpu/cpu_powerpc.c | 14 ++++----------
src/qemu/qemu_command.c | 11 ++++++++++-
5 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 20d81ae..ebab482 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -4067,6 +4067,7 @@
<choice>
<value>allow</value>
<value>forbid</value>
+ <value>compat</value>
</choice>
</attribute>
</optional>
diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c
index 9b7fbb0..e12d3db 100644
--- a/src/conf/cpu_conf.c
+++ b/src/conf/cpu_conf.c
@@ -47,7 +47,8 @@ VIR_ENUM_IMPL(virCPUMatch, VIR_CPU_MATCH_LAST,
VIR_ENUM_IMPL(virCPUFallback, VIR_CPU_FALLBACK_LAST,
"allow",
- "forbid")
+ "forbid",
+ "compat")
VIR_ENUM_IMPL(virCPUFeaturePolicy, VIR_CPU_FEATURE_LAST,
"force",
@@ -619,6 +620,7 @@ virCPUDefFormatBuf(virBufferPtr buf,
return 0;
formatModel = (def->mode == VIR_CPU_MODE_CUSTOM ||
+ def->mode == VIR_CPU_MODE_HOST_MODEL ||
(flags & VIR_DOMAIN_XML_UPDATE_CPU));
formatFallback = (def->type == VIR_CPU_TYPE_GUEST &&
(def->mode == VIR_CPU_MODE_HOST_MODEL ||
diff --git a/src/conf/cpu_conf.h b/src/conf/cpu_conf.h
index d45210b..69d8584 100644
--- a/src/conf/cpu_conf.h
+++ b/src/conf/cpu_conf.h
@@ -65,6 +65,7 @@ VIR_ENUM_DECL(virCPUMatch)
typedef enum {
VIR_CPU_FALLBACK_ALLOW,
VIR_CPU_FALLBACK_FORBID,
+ VIR_CPU_FALLBACK_COMPAT,
VIR_CPU_FALLBACK_LAST
} virCPUFallback;
diff --git a/src/cpu/cpu_powerpc.c b/src/cpu/cpu_powerpc.c
index d591c18..ad887fe 100644
--- a/src/cpu/cpu_powerpc.c
+++ b/src/cpu/cpu_powerpc.c
@@ -479,7 +479,8 @@ ppcDecode(virCPUDefPtr cpu,
goto cleanup;
}
- if (!cpuModelIsAllowed(model->name, models, nmodels)) {
+ if (cpu->fallback != VIR_CPU_FALLBACK_COMPAT &&
+ !cpuModelIsAllowed(model->name, models, nmodels)) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("CPU model %s is not supported by hypervisor"),
model->name);
@@ -562,8 +563,8 @@ ppcUpdate(virCPUDefPtr guest,
static virCPUDefPtr
ppcBaseline(virCPUDefPtr *cpus,
unsigned int ncpus,
- const char **models,
- unsigned int nmodels,
+ const char **models ATTRIBUTE_UNUSED,
+ unsigned int nmodels ATTRIBUTE_UNUSED,
unsigned int flags)
{
struct ppc_map *map = NULL;
@@ -583,13 +584,6 @@ ppcBaseline(virCPUDefPtr *cpus,
goto error;
}
- if (!cpuModelIsAllowed(model->name, models, nmodels)) {
- virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
- _("CPU model %s is not supported by hypervisor"),
- model->name);
- goto error;
- }
-
for (i = 0; i < ncpus; i++) {
const struct ppc_vendor *vnd;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index d60f274..3143bd8 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6221,7 +6221,9 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver,
*hasHwVirt = hasSVM > 0 ? true : false;
}
- if (cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH) {
+ if ((cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH) ||
+ ((cpu->mode == VIR_CPU_MODE_HOST_MODEL) &&
+ ARCH_IS_PPC64(def->os.arch))) {
const char *mode = virCPUModeTypeToString(cpu->mode);
if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_CPU_HOST)) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@@ -6236,6 +6238,13 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver,
goto cleanup;
}
virBufferAddLit(buf, "host");
+
+ if (ARCH_IS_PPC64(def->os.arch) &&
+ cpu->mode == VIR_CPU_MODE_HOST_MODEL &&
+ cpu->fallback == VIR_CPU_FALLBACK_COMPAT) {
+ virBufferAsprintf(buf, ",compat=%s", def->cpu->model);
+ }
+
} else {
if (VIR_ALLOC(guest) < 0)
goto cleanup;
--
1.8.3.1
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
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