From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60E91C4338F for ; Tue, 10 Aug 2021 18:54:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC06F60F02 for ; Tue, 10 Aug 2021 18:53:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org AC06F60F02 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:41656 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mDWsw-0003hu-8s for qemu-devel@archiver.kernel.org; Tue, 10 Aug 2021 14:53:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:32798) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mDWrx-0002Tm-Ez for qemu-devel@nongnu.org; Tue, 10 Aug 2021 14:52:57 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24580) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mDWrr-0004fc-Ls for qemu-devel@nongnu.org; Tue, 10 Aug 2021 14:52:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628621569; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IaZEvofZD0Yrso8Llr5b7ZleegW2NnD/54H1Y1DVYAk=; b=UQvf3Cit1rtcyoQC5j2AD5XrmjIyTRuCIZM4AKClO1XPoM79fJFWi1n1RdUZ2bStp5Pvss Ur3NISjPHsBAghjCbtQ+cZrxXbCaF9Fx9mHhSmww7mQ8DhDjT5d0PJvtUsUt7n5rw0jK+H vZBGGz8eWSRPMbbX8o0q6ziyScrfaOY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-275-IzBc6EIVMsShNWDFYJGuMA-1; Tue, 10 Aug 2021 14:52:48 -0400 X-MC-Unique: IzBc6EIVMsShNWDFYJGuMA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A06C31853029; Tue, 10 Aug 2021 18:52:46 +0000 (UTC) Received: from localhost (unknown [10.22.32.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id F33BA5C1A1; Tue, 10 Aug 2021 18:52:45 +0000 (UTC) Date: Tue, 10 Aug 2021 14:52:45 -0400 From: Eduardo Habkost To: Valeriy Vdovin Subject: Re: [PATCH v14] qapi: introduce 'query-x86-cpuid' QMP command. Message-ID: <20210810185245.kivvmrmvew6e5xtr@habkost.net> References: <20210810065131.2849-1-valery.vdovin.s@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210810065131.2849-1-valery.vdovin.s@gmail.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Received-SPF: pass client-ip=216.205.24.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.704, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Thomas Huth , Vladimir Sementsov-Ogievskiy , kvm@vger.kernel.org, Marcelo Tosatti , Richard Henderson , qemu-devel@nongnu.org, Markus Armbruster , Valeriy Vdovin , Denis Lunev , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Aug 10, 2021 at 09:51:31AM +0300, Valeriy Vdovin wrote: > From: Valeriy Vdovin > > Introducing new QMP command 'query-x86-cpuid'. This command can be used to > get virtualized cpu model info generated by QEMU during VM initialization in > the form of cpuid representation. > > Diving into more details about virtual CPU generation: QEMU first parses '-cpu' > command line option. From there it takes the name of the model as the basis for > feature set of the new virtual CPU. After that it uses trailing '-cpu' options, > that state if additional cpu features should be present on the virtual CPU or > excluded from it (tokens '+'/'-' or '=on'/'=off'). > After that QEMU checks if the host's cpu can actually support the derived > feature set and applies host limitations to it. > After this initialization procedure, virtual CPU has it's model and > vendor names, and a working feature set and is ready for identification > instructions such as CPUID. > > To learn exactly how virtual CPU is presented to the guest machine via CPUID > instruction, new QMP command can be used. By calling 'query-x86-cpuid' > command, one can get a full listing of all CPUID leaves with subleaves which are > supported by the initialized virtual CPU. > > Other than debug, the command is useful in cases when we would like to > utilize QEMU's virtual CPU initialization routines and put the retrieved > values into kernel CPUID overriding mechanics for more precise control > over how various processes perceive its underlying hardware with > container processes as a good example. > > The command is specific to x86. It is currenly only implemented for KVM acceleator. > > Output format: > The output is a plain list of leaf/subleaf argument combinations, that > return 4 words in registers EAX, EBX, ECX, EDX. > > Use example: > qmp_request: { > "execute": "query-x86-cpuid" > } > > qmp_response: { > "return": [ > { > "eax": 1073741825, > "edx": 77, > "in-eax": 1073741824, > "ecx": 1447775574, > "ebx": 1263359563 > }, > { > "eax": 16777339, > "edx": 0, > "in-eax": 1073741825, > "ecx": 0, > "ebx": 0 > }, > { > "eax": 13, > "edx": 1231384169, > "in-eax": 0, > "ecx": 1818588270, > "ebx": 1970169159 > }, > { > "eax": 198354, > "edx": 126614527, > "in-eax": 1, > "ecx": 2176328193, > "ebx": 2048 > }, > .... > { > "eax": 12328, > "edx": 0, > "in-eax": 2147483656, > "ecx": 0, > "ebx": 0 > } > ] > } > > Signed-off-by: Valeriy Vdovin > --- > v2: - Removed leaf/subleaf iterators. > - Modified cpu_x86_cpuid to return false in cases when count is > greater than supported subleaves. > v3: - Fixed structure name coding style. > - Added more comments > - Ensured buildability for non-x86 targets. > v4: - Fixed cpu_x86_cpuid return value logic and handling of 0xA leaf. > - Fixed comments. > - Removed target check in qmp_query_cpu_model_cpuid. > v5: - Added error handling code in qmp_query_cpu_model_cpuid > v6: - Fixed error handling code. Added method to query_error_class > v7: - Changed implementation in favor of cached cpuid_data for > KVM_SET_CPUID2 > v8: - Renamed qmp method to query-kvm-cpuid and some fields in response. > - Modified documentation to qmp method > - Removed helper struct declaration > v9: - Renamed 'in_eax' / 'in_ecx' fields to 'in-eax' / 'in-ecx' > - Pasted more complete response to commit message. > v10: > - Subject changed > - Fixes in commit message > - Small fixes in QMP command docs > v11: > - Added explanation about CONFIG_KVM to the commit message. > v12: > - Changed title from query-kvm-cpuid to query-x86-cpuid > - Removed CONFIG_KVM ifdefs > - Added detailed error messages for some stub/unimplemented cases. > v13: > - Tagged with since 6.2 > v14: > - Rebased to latest master 632eda54043d6f26ff87dac16233e14b4708b967 > - Added note about error return cases in api documentation. > > qapi/machine-target.json | 46 ++++++++++++++++++++++++++++++++++ > softmmu/cpus.c | 2 +- > target/i386/kvm/kvm-stub.c | 10 ++++++++ > target/i386/kvm/kvm.c | 51 ++++++++++++++++++++++++++++++++++++++ > tests/qtest/qmp-cmd-test.c | 1 + > 5 files changed, 109 insertions(+), 1 deletion(-) > > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index e7811654b7..71648a4f56 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -329,3 +329,49 @@ > ## > { 'command': 'query-cpu-definitions', 'returns': ['CpuDefinitionInfo'], > 'if': 'defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_I386) || defined(TARGET_S390X) || defined(TARGET_MIPS)' } > + > +## > +# @CpuidEntry: > +# > +# A single entry of a CPUID response. > +# > +# One entry holds full set of information (leaf) returned to the guest > +# in response to it calling a CPUID instruction with eax, ecx used as > +# the arguments to that instruction. ecx is an optional argument as > +# not all of the leaves support it. > +# > +# @in-eax: CPUID argument in eax > +# @in-ecx: CPUID argument in ecx > +# @eax: CPUID result in eax > +# @ebx: CPUID result in ebx > +# @ecx: CPUID result in ecx > +# @edx: CPUID result in edx > +# > +# Since: 6.2 > +## > +{ 'struct': 'CpuidEntry', > + 'data': { 'in-eax' : 'uint32', > + '*in-ecx' : 'uint32', > + 'eax' : 'uint32', > + 'ebx' : 'uint32', > + 'ecx' : 'uint32', > + 'edx' : 'uint32' > + }, > + 'if': 'defined(TARGET_I386)' } > + > +## > +# @query-x86-cpuid: > +# > +# Returns raw data from the emulated CPUID table for the first VCPU. > +# The emulated CPUID table defines the response to the CPUID > +# instruction when executed by the guest operating system. > +# > +# > +# Returns: a list of CpuidEntry. Returns error when qemu is configured with > +# --disable-kvm flag or if qemu is run with any other accelerator than KVM. > +# > +# Since: 6.2 > +## > +{ 'command': 'query-x86-cpuid', > + 'returns': ['CpuidEntry'], > + 'if': 'defined(TARGET_I386)' } > diff --git a/softmmu/cpus.c b/softmmu/cpus.c > index 071085f840..8501081897 100644 > --- a/softmmu/cpus.c > +++ b/softmmu/cpus.c > @@ -129,7 +129,7 @@ void hw_error(const char *fmt, ...) > /* > * The chosen accelerator is supposed to register this. > */ > -static const AccelOpsClass *cpus_accel; > +const AccelOpsClass *cpus_accel; > > void cpu_synchronize_all_states(void) > { > diff --git a/target/i386/kvm/kvm-stub.c b/target/i386/kvm/kvm-stub.c > index f6e7e4466e..9eb04d908f 100644 > --- a/target/i386/kvm/kvm-stub.c > +++ b/target/i386/kvm/kvm-stub.c > @@ -12,6 +12,7 @@ > #include "qemu/osdep.h" > #include "cpu.h" > #include "kvm_i386.h" > +#include "qapi/error.h" > > #ifndef __OPTIMIZE__ > bool kvm_has_smm(void) > @@ -44,3 +45,12 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) > { > abort(); > } > + > +typedef struct CpuidEntryList CpuidEntryList; > +CpuidEntryList *qmp_query_x86_cpuid(Error **errp); > + > +CpuidEntryList *qmp_query_x86_cpuid(Error **errp) > +{ > + error_setg(errp, "Not implemented in --disable-kvm configuration"); > + return NULL; > +} > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index e69abe48e3..28e79cd0cf 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -20,11 +20,13 @@ > > #include > #include "standard-headers/asm-x86/kvm_para.h" > +#include "qapi/qapi-commands-machine-target.h" > > #include "cpu.h" > #include "host-cpu.h" > #include "sysemu/sysemu.h" > #include "sysemu/hw_accel.h" > +#include "sysemu/accel-ops.h" > #include "sysemu/kvm_int.h" > #include "sysemu/runstate.h" > #include "kvm_i386.h" > @@ -1540,6 +1542,51 @@ static Error *invtsc_mig_blocker; > > #define KVM_MAX_CPUID_ENTRIES 100 > > +struct kvm_cpuid2 *cpuid_data_cached; > +extern const AccelOpsClass *cpus_accel; > + > +static inline int is_kvm_accel(AccelOpsClass *class) > +{ > + ObjectClass *parent_class; We normally call ObjectClass variables 'oc'. > + > + parent_class = &class->parent_class; The right way to cast a class/object to a different type is to use the type casting macros. e.g.: oc = OBJECT_CLASS(class); > + return strcmp(object_class_get_name(parent_class), > + "kvm-accel-ops") == 0; You should never do a string comparison of the QOM type name to decide what to do. If you want to know if a class implements a specific type, you can just call: object_class_dynamic_cast(class, TYPE_KVM_ACCEL) In either case, this function can probably be deleted and replaced with a simple kvm_enabled() call (see below). > +} > + > +CpuidEntryList *qmp_query_x86_cpuid(Error **errp) > +{ > + int i; > + struct kvm_cpuid_entry2 *kvm_entry; > + CpuidEntryList *head = NULL, **tail = &head; > + CpuidEntry *entry; > + > + if (!cpuid_data_cached) { > + if (cpus_accel && !is_kvm_accel((AccelOpsClass *)cpus_accel)) This can be replaced by a kvm_enabled() check. Also, I suggest avoid nesting conditionals when possible. e.g.: if (!kvm_enabled()) { error_setg(...); return NULL; } if (!cpuid_data_cached) { error_setg(...); return NULL; } > + error_setg(errp, "Not implemented for non-kvm accel"); > + else > + error_setg(errp, "VCPU was not initialized yet"); > + return NULL; > + } > + > + for (i = 0; i < cpuid_data_cached->nent; ++i) { > + kvm_entry = &cpuid_data_cached->entries[i]; > + entry = g_malloc0(sizeof(*entry)); > + entry->in_eax = kvm_entry->function; > + if (kvm_entry->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) { > + entry->in_ecx = kvm_entry->index; > + entry->has_in_ecx = true; > + } > + entry->eax = kvm_entry->eax; > + entry->ebx = kvm_entry->ebx; > + entry->ecx = kvm_entry->ecx; > + entry->edx = kvm_entry->edx; > + QAPI_LIST_APPEND(tail, entry); > + } > + > + return head; > +} > + > int kvm_arch_init_vcpu(CPUState *cs) > { > struct { > @@ -1923,6 +1970,10 @@ int kvm_arch_init_vcpu(CPUState *cs) > if (r) { > goto fail; > } > + if (!cpuid_data_cached) { > + cpuid_data_cached = g_malloc0(sizeof(cpuid_data)); > + memcpy(cpuid_data_cached, &cpuid_data, sizeof(cpuid_data)); > + } > > if (has_xsave) { > env->xsave_buf_len = sizeof(struct kvm_xsave); > diff --git a/tests/qtest/qmp-cmd-test.c b/tests/qtest/qmp-cmd-test.c > index c98b78d033..bd883f7f52 100644 > --- a/tests/qtest/qmp-cmd-test.c > +++ b/tests/qtest/qmp-cmd-test.c > @@ -46,6 +46,7 @@ static int query_error_class(const char *cmd) > { "query-balloon", ERROR_CLASS_DEVICE_NOT_ACTIVE }, > { "query-hotpluggable-cpus", ERROR_CLASS_GENERIC_ERROR }, > { "query-vm-generation-id", ERROR_CLASS_GENERIC_ERROR }, > + { "query-x86-cpuid", ERROR_CLASS_GENERIC_ERROR }, > { NULL, -1 } > }; > int i; > -- > 2.17.1 > -- Eduardo