From: Eduardo Habkost <ehabkost@redhat.com> To: Michael Mueller <mimu@linux.vnet.ibm.com> Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Gleb Natapov <gleb@kernel.org>, Alexander Graf <agraf@suse.de>, Christian Borntraeger <borntraeger@de.ibm.com>, "Jason J. Herne" <jjherne@linux.vnet.ibm.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Andreas Faerber <afaerber@suse.de>, Richard Henderson <rth@twiddle.net>, Daniel Hansel <daniel.hansel@linux.vnet.ibm.com> Subject: Re: [PATCH v4 11/15] target-s390x: New QMP command query-cpu-model Date: Wed, 1 Apr 2015 10:01:13 -0300 [thread overview] Message-ID: <20150401130113.GL7031@thinpad.lan.raisama.net> (raw) In-Reply-To: <20150331220909.4410e8c0@bee> On Tue, Mar 31, 2015 at 10:09:09PM +0200, Michael Mueller wrote: > On Tue, 31 Mar 2015 15:35:26 -0300 > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > On Mon, Mar 30, 2015 at 04:28:24PM +0200, Michael Mueller wrote: > > > This patch implements a new QMP request named 'query-cpu-model'. > > > It returns the cpu model of cpu 0 and its backing accelerator. > > > > > > request: > > > {"execute" : "query-cpu-model" } > > > > > > answer: > > > {"return" : {"name": "2827-ga2", "accel": "kvm" }} > > > > > > Alias names are resolved to their respective machine type and GA names > > > already during cpu instantiation. Thus, also a cpu model like 'host' > > > which is implemented as alias will return its normalized cpu model name. > > > > > > Furthermore the patch implements the following function: > > > > > > - s390_cpu_models_used(), returns true if S390 cpu models are in use > > > > > > Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com> > > > --- > > [...] > > > +static inline char *strdup_s390_cpu_name(S390CPUClass *cc) > > > +{ > > > + return g_strdup_printf("%04x-ga%u", cc->proc.type, cc->mach.ga); > > > +} > > > > How exactly is this information going to be used by clients? If getting > > the correct type and ga values is important for them, maybe you could > > add them as integer fields, instead of requiring clients to parse the > > CPU model name? > > The consumer don't need to parse the name, it is just important for them to have > distinctive names that correlate with the names returned by query-cpu-definitions. > Once the name of an active guest is known, e.g. ("2827-ga2", "kvm") a potential > migration target can be verified, i.e. its query-cpu-definitions answer for "kvm" > has to contain "2827-ga2" with the attribute runnable set to true. With that mechanism > also the largest common denominator can be calculated. That model will be used then. Understood. So the point is to really have a name that can be found at query-cpu-definitions. Makes sense. (BTW, if you reused strdup_s390_cpu_name() inside s390_cpu_compare_class_name() too, you would automatically ensure that query-cpus, query-cpu-definitions and s390_cpu_class_by_name() will always agree with each other). > > I also changed the above mentioned routine to map the cpu model none case: > > static inline char *strdup_s390_cpu_name(S390CPUClass *cc) > { > if (cpuid(cc->proc)) { > return g_strdup_printf("%04x-ga%u", cc->proc.type, cc->mach.ga); > } else { > return g_strdup("none"); > } > } What about: static const char *s390_cpu_name(S390CPUClass *cc) { return cc->model_name; } And then you can just set cc->model_name=_name inside S390_PROC_DEF (and set it to "none" inside s390_cpu_class_init()). I wonder if this class->model_name conversion could be made generic inside the CPU class. We already have a CPU::class_by_name() method, so it makes sense to have the opposite function too. (But I wouldn't mind making this s390-specific first, and converted later to generic code if appropriate). > > This implicitly will fail a comparison for cpu model ("none", "kvm") as that will > never be part of the query-cpu-definitions answer. I am not sure I follow. If ("none", "kvm") is never in the list, is "-cpu none -machine accel=kvm" always an invalid use case? (I don't understand completely the meaning of "-cpu none" yet. How does the CPU look like for the guest in this case? Is it possible to live-migrate when using -cpu none?) -- Eduardo
WARNING: multiple messages have this Message-ID (diff)
From: Eduardo Habkost <ehabkost@redhat.com> To: Michael Mueller <mimu@linux.vnet.ibm.com> Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org, Gleb Natapov <gleb@kernel.org>, linux-kernel@vger.kernel.org, Alexander Graf <agraf@suse.de>, qemu-devel@nongnu.org, Christian Borntraeger <borntraeger@de.ibm.com>, Daniel Hansel <daniel.hansel@linux.vnet.ibm.com>, "Jason J. Herne" <jjherne@linux.vnet.ibm.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Andreas Faerber <afaerber@suse.de>, Richard Henderson <rth@twiddle.net> Subject: Re: [Qemu-devel] [PATCH v4 11/15] target-s390x: New QMP command query-cpu-model Date: Wed, 1 Apr 2015 10:01:13 -0300 [thread overview] Message-ID: <20150401130113.GL7031@thinpad.lan.raisama.net> (raw) In-Reply-To: <20150331220909.4410e8c0@bee> On Tue, Mar 31, 2015 at 10:09:09PM +0200, Michael Mueller wrote: > On Tue, 31 Mar 2015 15:35:26 -0300 > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > On Mon, Mar 30, 2015 at 04:28:24PM +0200, Michael Mueller wrote: > > > This patch implements a new QMP request named 'query-cpu-model'. > > > It returns the cpu model of cpu 0 and its backing accelerator. > > > > > > request: > > > {"execute" : "query-cpu-model" } > > > > > > answer: > > > {"return" : {"name": "2827-ga2", "accel": "kvm" }} > > > > > > Alias names are resolved to their respective machine type and GA names > > > already during cpu instantiation. Thus, also a cpu model like 'host' > > > which is implemented as alias will return its normalized cpu model name. > > > > > > Furthermore the patch implements the following function: > > > > > > - s390_cpu_models_used(), returns true if S390 cpu models are in use > > > > > > Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com> > > > --- > > [...] > > > +static inline char *strdup_s390_cpu_name(S390CPUClass *cc) > > > +{ > > > + return g_strdup_printf("%04x-ga%u", cc->proc.type, cc->mach.ga); > > > +} > > > > How exactly is this information going to be used by clients? If getting > > the correct type and ga values is important for them, maybe you could > > add them as integer fields, instead of requiring clients to parse the > > CPU model name? > > The consumer don't need to parse the name, it is just important for them to have > distinctive names that correlate with the names returned by query-cpu-definitions. > Once the name of an active guest is known, e.g. ("2827-ga2", "kvm") a potential > migration target can be verified, i.e. its query-cpu-definitions answer for "kvm" > has to contain "2827-ga2" with the attribute runnable set to true. With that mechanism > also the largest common denominator can be calculated. That model will be used then. Understood. So the point is to really have a name that can be found at query-cpu-definitions. Makes sense. (BTW, if you reused strdup_s390_cpu_name() inside s390_cpu_compare_class_name() too, you would automatically ensure that query-cpus, query-cpu-definitions and s390_cpu_class_by_name() will always agree with each other). > > I also changed the above mentioned routine to map the cpu model none case: > > static inline char *strdup_s390_cpu_name(S390CPUClass *cc) > { > if (cpuid(cc->proc)) { > return g_strdup_printf("%04x-ga%u", cc->proc.type, cc->mach.ga); > } else { > return g_strdup("none"); > } > } What about: static const char *s390_cpu_name(S390CPUClass *cc) { return cc->model_name; } And then you can just set cc->model_name=_name inside S390_PROC_DEF (and set it to "none" inside s390_cpu_class_init()). I wonder if this class->model_name conversion could be made generic inside the CPU class. We already have a CPU::class_by_name() method, so it makes sense to have the opposite function too. (But I wouldn't mind making this s390-specific first, and converted later to generic code if appropriate). > > This implicitly will fail a comparison for cpu model ("none", "kvm") as that will > never be part of the query-cpu-definitions answer. I am not sure I follow. If ("none", "kvm") is never in the list, is "-cpu none -machine accel=kvm" always an invalid use case? (I don't understand completely the meaning of "-cpu none" yet. How does the CPU look like for the guest in this case? Is it possible to live-migrate when using -cpu none?) -- Eduardo
next prev parent reply other threads:[~2015-04-01 13:34 UTC|newest] Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-30 14:28 [PATCH v4 00/15] s390x cpu model implementation Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` [PATCH v4 01/15] Introduce stub routine cpu_desc_avail Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` [PATCH v4 02/15] target-s390x: Introduce cpu facilities Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 03/15] target-s390x: Generate facility defines per cpu model Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` [PATCH v4 04/15] target-s390x: Introduce cpu models Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 05/15] target-s390x: Define cpu model specific facility lists Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 06/15] target-s390x: Add cpu model alias definition routines Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` [PATCH v4 07/15] target-s390x: Update linux-headers/asm-s390/kvm.h Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 19:36 ` Christian Borntraeger 2015-03-30 19:36 ` [Qemu-devel] " Christian Borntraeger 2015-03-30 19:36 ` Christian Borntraeger 2015-03-31 7:25 ` Michael Mueller 2015-03-31 7:25 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` [PATCH v4 08/15] target-s390x: Add KVM VM attribute interface for cpu models Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 09/15] target-s390x: Add cpu class initialization routines Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 10/15] target-s390x: Prepare accelerator during cpu object realization Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 19:33 ` Eduardo Habkost 2015-03-30 19:33 ` [Qemu-devel] " Eduardo Habkost 2015-03-31 10:26 ` Michael Mueller 2015-03-31 10:26 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 11/15] target-s390x: New QMP command query-cpu-model Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 19:50 ` Eduardo Habkost 2015-03-30 19:50 ` [Qemu-devel] " Eduardo Habkost 2015-03-31 9:10 ` Michael Mueller 2015-03-31 9:10 ` Michael Mueller 2015-03-30 20:17 ` Eduardo Habkost 2015-03-30 20:17 ` [Qemu-devel] " Eduardo Habkost 2015-03-30 20:17 ` Eduardo Habkost 2015-03-30 20:20 ` [Qemu-devel] " Eric Blake 2015-03-30 20:20 ` Eric Blake 2015-03-30 20:20 ` Eric Blake 2015-03-31 13:16 ` [Qemu-devel] " Eduardo Habkost 2015-03-31 13:16 ` Eduardo Habkost 2015-03-31 11:21 ` Michael Mueller 2015-03-31 11:21 ` Michael Mueller 2015-03-31 18:28 ` Eduardo Habkost 2015-03-31 18:28 ` Eduardo Habkost 2015-03-30 20:19 ` Eric Blake 2015-03-30 20:19 ` Eric Blake 2015-03-31 7:56 ` Michael Mueller 2015-03-31 7:56 ` Michael Mueller 2015-03-31 7:56 ` Michael Mueller 2015-03-31 18:35 ` Eduardo Habkost 2015-03-31 18:35 ` [Qemu-devel] " Eduardo Habkost 2015-03-31 20:09 ` Michael Mueller 2015-03-31 20:09 ` [Qemu-devel] " Michael Mueller 2015-03-31 20:09 ` Michael Mueller 2015-04-01 13:01 ` Eduardo Habkost [this message] 2015-04-01 13:01 ` [Qemu-devel] " Eduardo Habkost 2015-04-01 16:31 ` Michael Mueller 2015-04-01 16:31 ` Michael Mueller 2015-04-01 16:59 ` Eduardo Habkost 2015-04-01 16:59 ` Eduardo Habkost 2015-04-01 16:59 ` Eduardo Habkost 2015-04-01 19:05 ` [Qemu-devel] " Michael Mueller 2015-04-01 19:05 ` Michael Mueller 2015-04-01 19:05 ` Michael Mueller 2015-04-01 19:10 ` [Qemu-devel] " Michael Mueller 2015-04-01 19:10 ` Michael Mueller 2015-04-01 23:05 ` Eduardo Habkost 2015-04-01 23:05 ` Eduardo Habkost 2015-04-01 23:05 ` Eduardo Habkost 2015-04-02 7:09 ` [Qemu-devel] " Michael Mueller 2015-04-02 7:09 ` Michael Mueller 2015-04-02 7:09 ` Michael Mueller 2015-04-02 15:15 ` [Qemu-devel] " Eduardo Habkost 2015-04-02 15:15 ` Eduardo Habkost 2015-03-30 14:28 ` [PATCH v4 12/15] Add optional parameters to QMP command query-cpu-definitions Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 20:28 ` Eric Blake 2015-03-30 20:28 ` Eric Blake 2015-03-31 7:42 ` Michael Mueller 2015-03-31 7:42 ` Michael Mueller 2015-03-31 7:42 ` Michael Mueller 2015-03-31 19:46 ` Eduardo Habkost 2015-03-31 19:46 ` [Qemu-devel] " Eduardo Habkost 2015-03-31 19:46 ` Eduardo Habkost 2015-03-31 19:50 ` Eric Blake 2015-03-31 19:50 ` [Qemu-devel] " Eric Blake 2015-03-31 19:50 ` Eric Blake 2015-03-31 20:22 ` [Qemu-devel] " Michael Mueller 2015-03-31 20:22 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 13/15] target-s390x: Extend " Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 19:54 ` Eduardo Habkost 2015-03-30 19:54 ` [Qemu-devel] " Eduardo Habkost 2015-03-30 14:28 ` [PATCH v4 14/15] target-s390x: Introduce facility test routine Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller 2015-03-30 14:28 ` Michael Mueller 2015-03-30 14:28 ` [PATCH v4 15/15] target-s390x: Enable cpu model usage Michael Mueller 2015-03-30 14:28 ` [Qemu-devel] " Michael Mueller
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