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

From: Prerna Saxena <prerna(a)linux.vnet.ibm.com&gt; 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(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; --- 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