From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48270) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cCvEO-0004yd-2j for qemu-devel@nongnu.org; Fri, 02 Dec 2016 16:18:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cCvEM-0003Qc-Vg for qemu-devel@nongnu.org; Fri, 02 Dec 2016 16:18:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36966) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cCvEM-0003QG-Mp for qemu-devel@nongnu.org; Fri, 02 Dec 2016 16:18:54 -0500 From: Eduardo Habkost Date: Fri, 2 Dec 2016 19:18:13 -0200 Message-Id: <1480713496-11213-15-git-send-email-ehabkost@redhat.com> In-Reply-To: <1480713496-11213-1-git-send-email-ehabkost@redhat.com> References: <1480713496-11213-1-git-send-email-ehabkost@redhat.com> Subject: [Qemu-devel] [PATCH for-2.9 14/17] qapi: add static/migration-safe info to query-cpu-model-expansion List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Cornelia Huck , Christian Borntraeger , David Hildenbrand , libvir-list@redhat.com, Jiri Denemark , "Jason J. Herne" , Markus Armbruster , Eric Blake On x86, "-cpu host" enables some features that can't be represented by a static CPU model definition: cache info passthrough ("host-cache-info") and PMU passthrough ("pmu"). This means a type=static expansion of "host" can't include those features. A type=full expansion of "host", on the other hand, can include those features, but then the returned data won't be a static CPU model representation. Add a note to the documentation explaining that when using CPU models that include non-migration-safe features, users need to choose being precision and safety: a precise expansion of the CPU model (full) won't be safe (static), (because they would include pmu=on and host-cache-info=on), and a safe (static) expansion of the CPU model won't be precise. Architectures where CPU model expansion is always migration-safe (e.g. s390x) can simply do what they already do, and set 'migration-safe' and 'static' to true. Cc: Cornelia Huck Cc: Christian Borntraeger Cc: David Hildenbrand Cc: libvir-list@redhat.com Cc: Jiri Denemark Cc: "Jason J. Herne" Cc: Markus Armbruster Cc: Eric Blake Signed-off-by: Eduardo Habkost --- qapi-schema.json | 25 ++++++++++++++++++++++++- target-s390x/cpu_models.c | 4 ++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/qapi-schema.json b/qapi-schema.json index 8d113f8..a102534 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -3291,6 +3291,15 @@ # migration-safe, but allows tooling to get an insight and work with # model details. # +# Note: When a non-migration-safe CPU model is expanded in static mode, some +# features enabled by the CPU model may be omitted, because they can't be +# implemented by a static CPU model definition (e.g. cache info passthrough and +# PMU passthrough in x86). If you need an accurate representation of the +# features enabled by a non-migration-safe CPU model, use @full. If you need a +# static representation that will keep ABI compatibility even when changing QEMU +# version or machine-type, use @static (but keep in mind that some features may +# be omitted). +# # Since: 2.8.0 ## { 'enum': 'CpuModelExpansionType', @@ -3304,10 +3313,24 @@ # # @model: the expanded CpuModelInfo. # +# @migration-safe: the expanded CPU model in @model is a migration-safe +# CPU model. See @CpuDefinitionInfo.migration-safe. +# If expansion type was @static, this is always true. +# (since 2.9) +# +# @static: the expanded CPU model in @model is a static CPU model. +# See @CpuDefinitionInfo.static. If expansion type was @static, +# this is always true. +# (since 2.9) +# +# query-cpu-model-expansion with static expansion type should always +# return a static and migration-safe expansion. +# # Since: 2.8.0 ## { 'struct': 'CpuModelExpansionInfo', - 'data': { 'model': 'CpuModelInfo' } } + 'data': { 'model': 'CpuModelInfo', 'static': 'bool', + 'migration-safe': 'bool' } } ## diff --git a/target-s390x/cpu_models.c b/target-s390x/cpu_models.c index 5b66d33..f934add 100644 --- a/target-s390x/cpu_models.c +++ b/target-s390x/cpu_models.c @@ -448,6 +448,10 @@ CpuModelExpansionInfo *arch_query_cpu_model_expansion(CpuModelExpansionType type /* convert it back to a static representation */ expansion_info = g_malloc0(sizeof(*expansion_info)); expansion_info->model = g_malloc0(sizeof(*expansion_info->model)); + + /* We always expand to a static and migration-safe CpuModelInfo */ + expansion_info->q_static = true; + expansion_info->migration_safe = true; cpu_info_from_model(expansion_info->model, &s390_model, delta_changes); return expansion_info; } -- 2.7.4