| Message ID | 20190524081839.6228-2-tao3.xu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: Enable user wait instructions | expand |
On Fri, 24 May 2019 16:18:38 +0800 Tao Xu <tao3.xu@intel.com> wrote: > UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions. > Availability of the user wait instructions is indicated by the presence > of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. > > The patch enable the umonitor, umwait and tpause features in KVM. > Because umwait and tpause can put a (psysical) CPU into a power saving > state, by default we dont't expose it in kvm and provide a capability to > enable it. Use kvm capability to enable UMONITOR, UMWAIT and TPAUSE when > QEMU use "-overcommit cpu-pm=on, a VM can use UMONITOR, UMWAIT and TPAUSE > instructions. If the instruction causes a delay, the amount of time > delayed is called here the physical delay. The physical delay is first > computed by determining the virtual delay (the time to delay relative to > the VM’s timestamp counter). Otherwise, UMONITOR, UMWAIT and TPAUSE cause > an invalid-opcode exception(#UD). > > The release document ref below link: > https://software.intel.com/sites/default/files/\ > managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf > > Co-developed-by: Jingqi Liu <jingqi.liu@intel.com> > Signed-off-by: Jingqi Liu <jingqi.liu@intel.com> > Signed-off-by: Tao Xu <tao3.xu@intel.com> > --- > linux-headers/linux/kvm.h | 1 + > target/i386/cpu.c | 3 ++- > target/i386/cpu.h | 1 + > target/i386/kvm.c | 13 +++++++++++++ > 4 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h > index c8423e760c..86cc2dbdd0 100644 > --- a/linux-headers/linux/kvm.h > +++ b/linux-headers/linux/kvm.h > @@ -993,6 +993,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_ARM_SVE 170 > #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171 > #define KVM_CAP_ARM_PTRAUTH_GENERIC 172 > +#define KVM_CAP_ENABLE_USR_WAIT_PAUSE 173 > > #ifdef KVM_CAP_IRQ_ROUTING > No comment on the actual change, but please split out any linux-header changes so they can be replaced with a proper headers update when the code is merged.
On 6/4/2019 10:34 PM, Cornelia Huck wrote: > On Fri, 24 May 2019 16:18:38 +0800 > Tao Xu <tao3.xu@intel.com> wrote: > >> UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions. >> Availability of the user wait instructions is indicated by the presence >> of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. >> >> The patch enable the umonitor, umwait and tpause features in KVM. >> Because umwait and tpause can put a (psysical) CPU into a power saving >> state, by default we dont't expose it in kvm and provide a capability to >> enable it. Use kvm capability to enable UMONITOR, UMWAIT and TPAUSE when >> QEMU use "-overcommit cpu-pm=on, a VM can use UMONITOR, UMWAIT and TPAUSE >> instructions. If the instruction causes a delay, the amount of time >> delayed is called here the physical delay. The physical delay is first >> computed by determining the virtual delay (the time to delay relative to >> the VM’s timestamp counter). Otherwise, UMONITOR, UMWAIT and TPAUSE cause >> an invalid-opcode exception(#UD). >> >> The release document ref below link: >> https://software.intel.com/sites/default/files/\ >> managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf >> >> Co-developed-by: Jingqi Liu <jingqi.liu@intel.com> >> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com> >> Signed-off-by: Tao Xu <tao3.xu@intel.com> >> --- >> linux-headers/linux/kvm.h | 1 + >> target/i386/cpu.c | 3 ++- >> target/i386/cpu.h | 1 + >> target/i386/kvm.c | 13 +++++++++++++ >> 4 files changed, 17 insertions(+), 1 deletion(-) >> >> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h >> index c8423e760c..86cc2dbdd0 100644 >> --- a/linux-headers/linux/kvm.h >> +++ b/linux-headers/linux/kvm.h >> @@ -993,6 +993,7 @@ struct kvm_ppc_resize_hpt { >> #define KVM_CAP_ARM_SVE 170 >> #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171 >> #define KVM_CAP_ARM_PTRAUTH_GENERIC 172 >> +#define KVM_CAP_ENABLE_USR_WAIT_PAUSE 173 >> >> #ifdef KVM_CAP_IRQ_ROUTING >> > > No comment on the actual change, but please split out any linux-header > changes so they can be replaced with a proper headers update when the > code is merged. > Thank you for your review, I will update this patch when the kvm patch change a lot.
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h index c8423e760c..86cc2dbdd0 100644 --- a/linux-headers/linux/kvm.h +++ b/linux-headers/linux/kvm.h @@ -993,6 +993,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_SVE 170 #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172 +#define KVM_CAP_ENABLE_USR_WAIT_PAUSE 173 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 2df56fa977..c2ad7866a5 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1057,7 +1057,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = { .type = CPUID_FEATURE_WORD, .feat_names = { NULL, "avx512vbmi", "umip", "pku", - NULL /* ospke */, NULL, "avx512vbmi2", NULL, + NULL /* ospke */, "waitpkg", "avx512vbmi2", NULL, "gfni", "vaes", "vpclmulqdq", "avx512vnni", "avx512bitalg", NULL, "avx512-vpopcntdq", NULL, "la57", NULL, NULL, NULL, @@ -5196,6 +5196,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, &cpu->mwait.ecx, &cpu->mwait.edx); env->features[FEAT_1_ECX] |= CPUID_EXT_MONITOR; + env->features[FEAT_7_0_ECX] |= CPUID_7_0_ECX_WAITPKG; } } diff --git a/target/i386/cpu.h b/target/i386/cpu.h index fce6660bac..66fa61f02b 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -679,6 +679,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS]; #define CPUID_7_0_ECX_UMIP (1U << 2) #define CPUID_7_0_ECX_PKU (1U << 3) #define CPUID_7_0_ECX_OSPKE (1U << 4) +#define CPUID_7_0_ECX_WAITPKG (1U << 5) /* UMONITOR/UMWAIT/TPAUSE Instructions */ #define CPUID_7_0_ECX_VBMI2 (1U << 6) /* Additional VBMI Instrs */ #define CPUID_7_0_ECX_GFNI (1U << 8) #define CPUID_7_0_ECX_VAES (1U << 9) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 3b29ce5c0d..b58fc7ab3a 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -389,6 +389,10 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, if (host_tsx_blacklisted()) { ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE); } + } else if (function == 7 && index == 0 && reg == R_ECX) { + if (enable_cpu_pm) { + ret |= CPUID_7_0_ECX_WAITPKG; + } } else if (function == 7 && index == 0 && reg == R_EDX) { /* * Linux v4.17-v4.20 incorrectly return ARCH_CAPABILITIES on SVM hosts. @@ -1654,6 +1658,15 @@ int kvm_arch_init(MachineState *ms, KVMState *s) error_report("kvm: guest stopping CPU not supported: %s", strerror(-ret)); } + + if (kvm_check_extension(s, KVM_CAP_ENABLE_USR_WAIT_PAUSE)) { + ret = kvm_vm_enable_cap(s, KVM_CAP_ENABLE_USR_WAIT_PAUSE, 0); + if (ret < 0) { + error_report("kvm: guest can't enable user-level" + " wait and pause: %s", + strerror(-ret)); + } + } } return 0;