Re: [libvirt] [v5][PATCH 2/4] PowerPC : Add support for launching VMs in 'compat' mode.

From: Prerna Saxena <prerna(a)linux.vnet.ibm.com&gt; Date: Tue, 28 Oct 2014 15:05:59 +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 exploit cpu mode 'host-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'> <model>power7</model> </cpu>

Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com&gt; Signed-off-by: Li Zhang <zhlcindy(a)linux.vnet.ibm.com&gt; Signed-off-by: Pradipta Kr. Banerjee <bpradip(a)in.ibm.com&gt; --- src/conf/cpu_conf.c | 1 + src/cpu/cpu_powerpc.c | 11 ++--------- src/qemu/qemu_command.c | 10 +++++++++- 3 files changed, 12 insertions(+), 10 deletions(-) diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c index 9b7fbb0..0e7a979 100644 --- a/src/conf/cpu_conf.c +++ b/src/conf/cpu_conf.c @@ -619,6 +619,7 @@ 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/cpu/cpu_powerpc.c b/src/cpu/cpu_powerpc.c index d591c18..4ea1835 100644 --- a/src/cpu/cpu_powerpc.c +++ b/src/cpu/cpu_powerpc.c @@ -562,8 +562,8 @@ 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 +583,6 @@ 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..34f6535 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 +6238,12 @@ qemuBuildCpuModelArgStr(virQEMUDriverPtr driver, goto cleanup; } virBufferAddLit(buf, "host"); + + if (ARCH_IS_PPC64(def->os.arch) && + cpu->mode == VIR_CPU_MODE_HOST_MODEL) { + virBufferAsprintf(buf, ",compat=%s", def->cpu->model); + } + } else { if (VIR_ALLOC(guest) < 0) goto cleanup;