| Message ID | 20211222123124.130107-1-vsementsov@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v16] 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. Please wrap your commit messages around column 70. > > 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> This needs review from x86 CPU maintainers. Eduardo? [...] > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index f5ec4bc172..0ac575b1b9 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -341,3 +341,49 @@ > '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. > +# > +# > +# 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. Long line, please wrap around column 70. > +# > +# Since: 7.0 > +## > +{ 'command': 'x-query-x86-cpuid', > + 'returns': ['CpuidEntry'], > + 'if': 'TARGET_I386' } Needs feature 'unstable' now; see commit a3c45b3e62 'qapi: New special feature flag "unstable"' and also commit 57df0dff1a "qapi: Extend -compat to set policy for unstable interfaces". Incremental patch appended for your convenience. diff --git a/qapi/machine-target.json b/qapi/machine-target.json index 0ac575b1b9..049fa48a35 100644 --- a/qapi/machine-target.json +++ b/qapi/machine-target.json @@ -378,6 +378,8 @@ # 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. @@ -386,4 +388,5 @@ ## { 'command': 'x-query-x86-cpuid', 'returns': ['CpuidEntry'], - 'if': 'TARGET_I386' } + 'if': 'TARGET_I386', + 'features': [ 'unstable' ] }
19.01.2022 17:37, Markus Armbruster wrote: > 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. > > Please wrap your commit messages around column 70. > >> >> 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> > > This needs review from x86 CPU maintainers. Eduardo? > > [...] > >> diff --git a/qapi/machine-target.json b/qapi/machine-target.json >> index f5ec4bc172..0ac575b1b9 100644 >> --- a/qapi/machine-target.json >> +++ b/qapi/machine-target.json >> @@ -341,3 +341,49 @@ >> '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. >> +# >> +# >> +# 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. > > Long line, please wrap around column 70. > >> +# >> +# Since: 7.0 >> +## >> +{ 'command': 'x-query-x86-cpuid', >> + 'returns': ['CpuidEntry'], >> + 'if': 'TARGET_I386' } > > Needs feature 'unstable' now; see commit a3c45b3e62 'qapi: New special > feature flag "unstable"' and also commit 57df0dff1a "qapi: Extend > -compat to set policy for unstable interfaces". Incremental patch > appended for your convenience. > > > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index 0ac575b1b9..049fa48a35 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -378,6 +378,8 @@ > # 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. > @@ -386,4 +388,5 @@ > ## > { 'command': 'x-query-x86-cpuid', > 'returns': ['CpuidEntry'], > - 'if': 'TARGET_I386' } > + 'if': 'TARGET_I386', > + 'features': [ 'unstable' ] } > Thanks! I'll resend for convenience.
diff --git a/qapi/machine-target.json b/qapi/machine-target.json index f5ec4bc172..0ac575b1b9 100644 --- a/qapi/machine-target.json +++ b/qapi/machine-target.json @@ -341,3 +341,49 @@ '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. +# +# +# 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' } 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..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 13f8e30c2a..b7f6c7fcec 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" @@ -1564,6 +1566,44 @@ 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 { @@ -1980,6 +2020,10 @@ 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;