[libvirt] [PATCH 2/4] PowerPC : Add support for launching VMs in 'compat' mode.
Prerna Saxena
prerna at linux.vnet.ibm.com
Fri Oct 10 10:12:41 UTC 2014
>From 7228aacaa4b24907b1cbf33838ada8fb81890419 Mon Sep 17 00:00:00 2001
From: Prerna Saxena <prerna at linux.vnet.ibm.com>
Date: Tue, 7 Oct 2014 10:53:08 +0530
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='custom' match='exact'>
<model fallback='compat'>power7</model>
</cpu>
This has been introduced as a new mode since the behaviour of a guest in
compat mode is different from running natively on an older PowerISA.
Also, checks to cpuModelIsAllowed() have been removed, since QEMU for
PowerKVM no longer supports specifying a non-host CPU model using
'-cpu XXX'.
Signed-off-by: Prerna Saxena <prerna at linux.vnet.ibm.com>
Signed-off-by: Li Zhang <zhlcindy at linux.vnet.ibm.com>
Signed-off-by: Pradipta Kr. Banerjee <bpradip at in.ibm.com>
---
docs/schemas/domaincommon.rng | 1 +
src/conf/cpu_conf.c | 3 ++-
src/conf/cpu_conf.h | 1 +
src/cpu/cpu_powerpc.c | 22 ++++------------------
src/qemu/qemu_command.c | 13 +++++++++++--
5 files changed, 19 insertions(+), 21 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..32fd54f 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",
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..9ab33c2 100644
--- a/src/cpu/cpu_powerpc.c
+++ b/src/cpu/cpu_powerpc.c
@@ -458,8 +458,8 @@ ppcCompare(virCPUDefPtr host,
static int
ppcDecode(virCPUDefPtr cpu,
const virCPUData *data,
- const char **models,
- unsigned int nmodels,
+ const char **models ATTRIBUTE_UNUSED,
+ unsigned int nmodels ATTRIBUTE_UNUSED,
const char *preferred ATTRIBUTE_UNUSED,
unsigned int flags)
{
@@ -479,13 +479,6 @@ ppcDecode(virCPUDefPtr cpu,
goto cleanup;
}
- if (!cpuModelIsAllowed(model->name, models, nmodels)) {
- virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
- _("CPU model %s is not supported by hypervisor"),
- model->name);
- goto cleanup;
- }
-
if (VIR_STRDUP(cpu->model, model->name) < 0 ||
(model->vendor && VIR_STRDUP(cpu->vendor, model->vendor->name) < 0)) {
goto cleanup;
@@ -562,8 +555,8 @@ 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 +576,6 @@ 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 80ec9e8..74dc9d2 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,
@@ -6260,7 +6262,14 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver,
goto cleanup;
}
- virBufferAdd(buf, guest->model, -1);
+ if (ARCH_IS_PPC64(def->os.arch) &&
+ cpu->fallback == VIR_CPU_FALLBACK_COMPAT) {
+ virBufferAddLit(buf, "host");
+ virBufferAsprintf(buf, ",compat=%s", guest->model);
+ } else {
+ virBufferAdd(buf, guest->model, -1);
+ }
+
if (guest->vendor_id)
virBufferAsprintf(buf, ",vendor=%s", guest->vendor_id);
for (i = 0; i < guest->nfeatures; i++) {
--
1.8.3.1
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
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