| Message ID | 20220121163943.2720015-1-vsementsov@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v17] qapi: introduce 'x-query-x86-cpuid' QMP command. | expand |
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> writes: > From: Valeriy Vdovin <valeriy.vdovin@virtuozzo.com> > > 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": "x-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 <valeriy.vdovin@virtuozzo.com> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > > v17: wrap long lines, add QAPI feature 'unstable' [Markus] > > qapi/machine-target.json | 50 ++++++++++++++++++++++++++++++++++++++ > softmmu/cpus.c | 2 +- > target/i386/kvm/kvm-stub.c | 9 +++++++ > target/i386/kvm/kvm.c | 44 +++++++++++++++++++++++++++++++++ > tests/qtest/qmp-cmd-test.c | 1 + > 5 files changed, 105 insertions(+), 1 deletion(-) > > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index f5ec4bc172..1568e17e74 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -341,3 +341,53 @@ > 'TARGET_I386', > 'TARGET_S390X', > '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: 7.0 > +## > +{ 'struct': 'CpuidEntry', > + 'data': { 'in-eax' : 'uint32', > + '*in-ecx' : 'uint32', > + 'eax' : 'uint32', > + 'ebx' : 'uint32', > + 'ecx' : 'uint32', > + 'edx' : 'uint32' > + }, > + 'if': 'TARGET_I386' } > + > +## > +# @x-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. > +# > +# Features: > +# @unstable: This command is experimental. > +# > +# 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: 7.0 > +## > +{ 'command': 'x-query-x86-cpuid', > + 'returns': [ 'CpuidEntry' ], > + 'if': 'TARGET_I386', > + 'features': [ 'unstable' ] } QAPI schema Acked-by: Markus Armbruster <armbru@redhat.com> [...]
Ping :) Any hope that we will merge it one day?) 21.01.2022 19:39, Vladimir Sementsov-Ogievskiy wrote: > From: Valeriy Vdovin <valeriy.vdovin@virtuozzo.com> > > 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": "x-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 <valeriy.vdovin@virtuozzo.com> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > > v17: wrap long lines, add QAPI feature 'unstable' [Markus] > > qapi/machine-target.json | 50 ++++++++++++++++++++++++++++++++++++++ > softmmu/cpus.c | 2 +- > target/i386/kvm/kvm-stub.c | 9 +++++++ > target/i386/kvm/kvm.c | 44 +++++++++++++++++++++++++++++++++ > tests/qtest/qmp-cmd-test.c | 1 + > 5 files changed, 105 insertions(+), 1 deletion(-) > > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index f5ec4bc172..1568e17e74 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -341,3 +341,53 @@ > 'TARGET_I386', > 'TARGET_S390X', > '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: 7.0 > +## > +{ 'struct': 'CpuidEntry', > + 'data': { 'in-eax' : 'uint32', > + '*in-ecx' : 'uint32', > + 'eax' : 'uint32', > + 'ebx' : 'uint32', > + 'ecx' : 'uint32', > + 'edx' : 'uint32' > + }, > + 'if': 'TARGET_I386' } > + > +## > +# @x-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. > +# > +# Features: > +# @unstable: This command is experimental. > +# > +# 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: 7.0 > +## > +{ 'command': 'x-query-x86-cpuid', > + 'returns': [ 'CpuidEntry' ], > + 'if': 'TARGET_I386', > + 'features': [ 'unstable' ] } > diff --git a/softmmu/cpus.c b/softmmu/cpus.c > index 23bca46b07..33045bf45c 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..71631e560d 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 +45,11 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) > { > abort(); > } > + > +CpuidEntryList *qmp_x_query_x86_cpuid(Error **errp); > + > +CpuidEntryList *qmp_x_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 2c8feb4a6f..eb73869039 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -20,11 +20,13 @@ > > #include <linux/kvm.h> > #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" > @@ -1565,6 +1567,44 @@ static Error *invtsc_mig_blocker; > > #define KVM_MAX_CPUID_ENTRIES 100 > > +struct kvm_cpuid2 *cpuid_data_cached; > + > + > +CpuidEntryList *qmp_x_query_x86_cpuid(Error **errp) > +{ > + int i; > + struct kvm_cpuid_entry2 *kvm_entry; > + CpuidEntryList *head = NULL, **tail = &head; > + CpuidEntry *entry; > + > + if (!kvm_enabled()) { > + error_setg(errp, "Not implemented for non-kvm accel"); > + return NULL; > + } > + > + if (!cpuid_data_cached) { > + 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 { > @@ -1981,6 +2021,10 @@ 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 7f103ea3fd..94d9184a84 100644 > --- a/tests/qtest/qmp-cmd-test.c > +++ b/tests/qtest/qmp-cmd-test.c > @@ -54,6 +54,7 @@ static int query_error_class(const char *cmd) > /* Only valid with accel=tcg */ > { "x-query-jit", ERROR_CLASS_GENERIC_ERROR }, > { "x-query-opcount", ERROR_CLASS_GENERIC_ERROR }, > + { "x-query-x86-cpuid", ERROR_CLASS_GENERIC_ERROR }, > { NULL, -1 } > }; > int i; >
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> writes:
> Ping :) Any hope that we will merge it one day?)
Up to the x86 CPU maintainers: Paolo & Marcelo.
diff --git a/qapi/machine-target.json b/qapi/machine-target.json index f5ec4bc172..1568e17e74 100644 --- a/qapi/machine-target.json +++ b/qapi/machine-target.json @@ -341,3 +341,53 @@ 'TARGET_I386', 'TARGET_S390X', '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: 7.0 +## +{ 'struct': 'CpuidEntry', + 'data': { 'in-eax' : 'uint32', + '*in-ecx' : 'uint32', + 'eax' : 'uint32', + 'ebx' : 'uint32', + 'ecx' : 'uint32', + 'edx' : 'uint32' + }, + 'if': 'TARGET_I386' } + +## +# @x-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. +# +# Features: +# @unstable: This command is experimental. +# +# 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: 7.0 +## +{ 'command': 'x-query-x86-cpuid', + 'returns': [ 'CpuidEntry' ], + 'if': 'TARGET_I386', + 'features': [ 'unstable' ] } diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 23bca46b07..33045bf45c 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..71631e560d 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 +45,11 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) { abort(); } + +CpuidEntryList *qmp_x_query_x86_cpuid(Error **errp); + +CpuidEntryList *qmp_x_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 2c8feb4a6f..eb73869039 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -20,11 +20,13 @@ #include <linux/kvm.h> #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" @@ -1565,6 +1567,44 @@ static Error *invtsc_mig_blocker; #define KVM_MAX_CPUID_ENTRIES 100 +struct kvm_cpuid2 *cpuid_data_cached; + + +CpuidEntryList *qmp_x_query_x86_cpuid(Error **errp) +{ + int i; + struct kvm_cpuid_entry2 *kvm_entry; + CpuidEntryList *head = NULL, **tail = &head; + CpuidEntry *entry; + + if (!kvm_enabled()) { + error_setg(errp, "Not implemented for non-kvm accel"); + return NULL; + } + + if (!cpuid_data_cached) { + 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 { @@ -1981,6 +2021,10 @@ 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 7f103ea3fd..94d9184a84 100644 --- a/tests/qtest/qmp-cmd-test.c +++ b/tests/qtest/qmp-cmd-test.c @@ -54,6 +54,7 @@ static int query_error_class(const char *cmd) /* Only valid with accel=tcg */ { "x-query-jit", ERROR_CLASS_GENERIC_ERROR }, { "x-query-opcount", ERROR_CLASS_GENERIC_ERROR }, + { "x-query-x86-cpuid", ERROR_CLASS_GENERIC_ERROR }, { NULL, -1 } }; int i;