On 05/07/2018 10:45, Hu, Robert wrote:
>> This should be a CPU feature, not a machine feature. As mentioned in the
>> review of the kernel patch, please work with Robert to use the same
>> infrastructure for both MSR_TEST_CTL and MSR_IA32_ARCH_CAPABILITIES.
>>
>> (Robert, does IceLake have this feature? If so, we cannot create the CPU
>> model
>> until everything is in place).
>
> [Robert Hoo]
> Hi Paolo,
> This is not an Icelake feature.
So why is Intel pushing operating system code for half-baked features?
This "MSRs are the new CPUID" attitude must stop.
Paolo
>> BTW, why is the availability of the feature not exposed with a CPUID bit? It
>> doesn't make much sense.
>>
>> Paolo
>>
>>> Signed-off-by: Jingqi Liu <jingqi....@intel.com>
>>> ---
>>> accel/kvm/kvm-all.c | 10 ++++++++++
>>> hw/core/machine.c | 19 +++++++++++++++++++
>>> include/hw/boards.h | 1 +
>>> linux-headers/linux/kvm.h | 1 +
>>> qemu-options.hx | 3 +++
>>> 5 files changed, 34 insertions(+)
>>>
>>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index
>>> eb7db92..e960a4d 100644
>>> --- a/accel/kvm/kvm-all.c
>>> +++ b/accel/kvm/kvm-all.c
>>> @@ -1699,6 +1699,16 @@ static int kvm_init(MachineState *ms)
>>>
>>> s->sync_mmu = !!kvm_vm_check_extension(kvm_state,
>>> KVM_CAP_SYNC_MMU);
>>>
>>> + if (ms->split_lock_ac &&
>>> + kvm_check_extension(s, KVM_CAP_X86_SPLIT_LOCK_AC)) {
>>> + ret = kvm_vm_enable_cap(s, KVM_CAP_X86_SPLIT_LOCK_AC, 0);
>>> + if (ret) {
>>> + fprintf(stderr, "Could not enable the feature that #AC
>>> exception"
>>> + "will be generated for split lock accesses!\n");
>>> + goto err;
>>> + }
>>> + }
>>> +
>>> return 0;
>>>
>>> err:
>>> diff --git a/hw/core/machine.c b/hw/core/machine.c index
>>> 617e5f8..e054119 100644
>>> --- a/hw/core/machine.c
>>> +++ b/hw/core/machine.c
>>> @@ -350,6 +350,22 @@ static void machine_set_memory_encryption(Object
>> *obj, const char *value,
>>> ms->memory_encryption = g_strdup(value); }
>>>
>>> +static void machine_set_split_lock_ac(Object *obj, bool value,
>>> + Error **errp) {
>>> + MachineState *ms = MACHINE(obj);
>>> +
>>> + ms->split_lock_ac = value;
>>> +}
>>> +
>>> +static bool machine_get_split_lock_ac(Object *obj, Error **errp) {
>>> + MachineState *ms = MACHINE(obj);
>>> +
>>> + return ms->split_lock_ac;
>>> +}
>>> +
>>> +
>>> void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const
>>> char *type) {
>>> strList *item = g_new0(strList, 1); @@ -634,6 +650,9 @@ static
>>> void machine_class_init(ObjectClass *oc, void *data)
>>> &error_abort);
>>> object_class_property_set_description(oc, "memory-encryption",
>>> "Set memory encyption object to use", &error_abort);
>>> + object_class_property_add_bool(oc, "split-lock-ac",
>>> + machine_get_split_lock_ac, machine_set_split_lock_ac,
>>> + &error_abort);
>>> }
>>>
>>> static void machine_class_base_init(ObjectClass *oc, void *data) diff
>>> --git a/include/hw/boards.h b/include/hw/boards.h index
>>> 79069dd..9c1e2c0 100644
>>> --- a/include/hw/boards.h
>>> +++ b/include/hw/boards.h
>>> @@ -256,6 +256,7 @@ struct MachineState {
>>> bool suppress_vmdesc;
>>> bool enforce_config_section;
>>> bool enable_graphics;
>>> + bool split_lock_ac;
>>> char *memory_encryption;
>>> DeviceMemoryState *device_memory;
>>>
>>> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
>>> index 98f389a..4bfa879 100644
>>> --- a/linux-headers/linux/kvm.h
>>> +++ b/linux-headers/linux/kvm.h
>>> @@ -949,6 +949,7 @@ struct kvm_ppc_resize_hpt { #define
>>> KVM_CAP_GET_MSR_FEATURES 153 #define KVM_CAP_HYPERV_EVENTFD
>> 154
>>> #define KVM_CAP_HYPERV_TLBFLUSH 155
>>> +#define KVM_CAP_X86_SPLIT_LOCK_AC 156
>>>
>>> #ifdef KVM_CAP_IRQ_ROUTING
>>>
>>> diff --git a/qemu-options.hx b/qemu-options.hx index 81b1e99..935cefe
>>> 100644
>>> --- a/qemu-options.hx
>>> +++ b/qemu-options.hx
>>> @@ -44,6 +44,7 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
>>> " nvdimm=on|off controls NVDIMM support (default=off)\n"
>>> " enforce-config-section=on|off enforce configuration
>>> section
>> migration (default=off)\n"
>>> " s390-squash-mcss=on|off (deprecated) controls support
>>> for
>> squashing into default css (default=off)\n"
>>> + " split-lock-ac=on|off controls support #AC exception
>>> for split
>> locked accesses (default=off)\n"
>>> " memory-encryption=@var{} memory encryption object to
>>> use
>> (default=none)\n",
>>> QEMU_ARCH_ALL)
>>> STEXI
>>> @@ -113,6 +114,8 @@ NOTE: this parameter is deprecated. Please use
>>> @option{-global} @option{migration.send-configuration}=@var{on|off}
>> instead.
>>> @item memory-encryption=@var{}
>>> Memory encryption object to use. The default is none.
>>> +@item split-lock-ac=on|off
>>> +Enables or disables #AC exception for split locked accesses.
>>> @end table
>>> ETEXI
>>>
>>>
>
