Re: [Qemu-devel] [patch QEMU] kvm: i386: halt poll control MSR support

[Paolo Bonzini]

On 04/06/19 01:04, Marcelo Tosatti wrote:
> (CC'ing qemu devel)
> 
> Add support for halt poll control MSR: save/restore, migration
> and new feature name.
> 
> The purpose of this MSR is to allow the guest to disable
> host halt poll.
> 
> Signed-off-by: Marcelo Tosatti <address@hidden>
> 
> diff --git a/include/standard-headers/asm-x86/kvm_para.h 
> b/include/standard-headers/asm-x86/kvm_para.h
> index 35cd8d6..e171514 100644
> --- a/include/standard-headers/asm-x86/kvm_para.h
> +++ b/include/standard-headers/asm-x86/kvm_para.h
> @@ -29,6 +29,7 @@
>  #define KVM_FEATURE_PV_TLB_FLUSH     9
>  #define KVM_FEATURE_ASYNC_PF_VMEXIT  10
>  #define KVM_FEATURE_PV_SEND_IPI      11
> +#define KVM_FEATURE_POLL_CONTROL     12
>  
>  #define KVM_HINTS_REALTIME      0
>  
> @@ -47,6 +48,7 @@
>  #define MSR_KVM_ASYNC_PF_EN 0x4b564d02
>  #define MSR_KVM_STEAL_TIME  0x4b564d03
>  #define MSR_KVM_PV_EOI_EN      0x4b564d04
> +#define MSR_KVM_POLL_CONTROL 0x4b564d05
>  
>  struct kvm_steal_time {
>       uint64_t steal;
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index c1ab86d..1ca6944 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -903,7 +903,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = 
> {
>              "kvmclock", "kvm-nopiodelay", "kvm-mmu", "kvmclock",
>              "kvm-asyncpf", "kvm-steal-time", "kvm-pv-eoi", "kvm-pv-unhalt",
>              NULL, "kvm-pv-tlb-flush", NULL, "kvm-pv-ipi",
> -            NULL, NULL, NULL, NULL,
> +            "kvm-poll-control", NULL, NULL, NULL,
>              NULL, NULL, NULL, NULL,
>              NULL, NULL, NULL, NULL,
>              "kvmclock-stable-bit", NULL, NULL, NULL,
> @@ -3001,6 +3001,7 @@ static PropValue kvm_default_props[] = {
>      { "kvm-asyncpf", "on" },
>      { "kvm-steal-time", "on" },
>      { "kvm-pv-eoi", "on" },
> +    { "kvm-poll-control", "on" },
>      { "kvmclock-stable-bit", "on" },
>      { "x2apic", "on" },
>      { "acpi", "off" },
> @@ -5660,6 +5661,8 @@ static void x86_cpu_initfn(Object *obj)
>      object_property_add_alias(obj, "kvm_steal_time", obj, "kvm-steal-time", 
> &error_abort);
>      object_property_add_alias(obj, "kvm_pv_eoi", obj, "kvm-pv-eoi", 
> &error_abort);
>      object_property_add_alias(obj, "kvm_pv_unhalt", obj, "kvm-pv-unhalt", 
> &error_abort);
> +    object_property_add_alias(obj, "kvm_poll_control", obj, 
> "kvm-poll-control",
> +                              &error_abort);
>      object_property_add_alias(obj, "svm_lock", obj, "svm-lock", 
> &error_abort);
>      object_property_add_alias(obj, "nrip_save", obj, "nrip-save", 
> &error_abort);
>      object_property_add_alias(obj, "tsc_scale", obj, "tsc-scale", 
> &error_abort);
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index bd06523..21ed2f8 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1241,6 +1241,7 @@ typedef struct CPUX86State {
>      uint64_t steal_time_msr;
>      uint64_t async_pf_en_msr;
>      uint64_t pv_eoi_en_msr;
> +    uint64_t poll_control_msr;
>  
>      /* Partition-wide HV MSRs, will be updated only on the first vcpu */
>      uint64_t msr_hv_hypercall;
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 3b29ce5..a5e9cdf 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1369,6 +1369,8 @@ void kvm_arch_reset_vcpu(X86CPU *cpu)
>  
>          hyperv_x86_synic_reset(cpu);
>      }
> +    /* enabled by default */
> +    env->poll_control_msr = 1;
>  }
>  
>  void kvm_arch_do_init_vcpu(X86CPU *cpu)
> @@ -2059,6 +2061,11 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
>          if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_STEAL_TIME)) {
>              kvm_msr_entry_add(cpu, MSR_KVM_STEAL_TIME, env->steal_time_msr);
>          }
> +
> +        if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_POLL_CONTROL)) {
> +            kvm_msr_entry_add(cpu, MSR_KVM_POLL_CONTROL, 
> env->poll_control_msr);
> +        }
> +
>          if (has_architectural_pmu_version > 0) {
>              if (has_architectural_pmu_version > 1) {
>                  /* Stop the counter.  */
> @@ -2443,6 +2450,9 @@ static int kvm_get_msrs(X86CPU *cpu)
>      if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_STEAL_TIME)) {
>          kvm_msr_entry_add(cpu, MSR_KVM_STEAL_TIME, 0);
>      }
> +    if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_POLL_CONTROL)) {
> +        kvm_msr_entry_add(cpu, MSR_KVM_POLL_CONTROL, 1);
> +    }
>      if (has_architectural_pmu_version > 0) {
>          if (has_architectural_pmu_version > 1) {
>              kvm_msr_entry_add(cpu, MSR_CORE_PERF_FIXED_CTR_CTRL, 0);
> @@ -2677,6 +2687,10 @@ static int kvm_get_msrs(X86CPU *cpu)
>          case MSR_KVM_STEAL_TIME:
>              env->steal_time_msr = msrs[i].data;
>              break;
> +        case MSR_KVM_POLL_CONTROL: {
> +            env->poll_control_msr = msrs[i].data;
> +            break;
> +        }
>          case MSR_CORE_PERF_FIXED_CTR_CTRL:
>              env->msr_fixed_ctr_ctrl = msrs[i].data;
>              break;
> diff --git a/target/i386/machine.c b/target/i386/machine.c
> index 225b5d4..1c23e5e 100644
> --- a/target/i386/machine.c
> +++ b/target/i386/machine.c
> @@ -323,6 +323,14 @@ static bool steal_time_msr_needed(void *opaque)
>      return cpu->env.steal_time_msr != 0;
>  }
>  
> +/* Poll control MSR enabled by default */
> +static bool poll_control_msr_needed(void *opaque)
> +{
> +    X86CPU *cpu = opaque;
> +
> +    return cpu->env.poll_control_msr != 1;
> +}
> +
>  static const VMStateDescription vmstate_steal_time_msr = {
>      .name = "cpu/steal_time_msr",
>      .version_id = 1,
> @@ -356,6 +364,17 @@ static const VMStateDescription vmstate_pv_eoi_msr = {
>      }
>  };
>  
> +static const VMStateDescription vmstate_poll_control_msr = {
> +    .name = "cpu/poll_control_msr",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .needed = poll_control_msr_needed,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT64(env.poll_control_msr, X86CPU),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
>  static bool fpop_ip_dp_needed(void *opaque)
>  {
>      X86CPU *cpu = opaque;
> @@ -1062,6 +1081,7 @@ VMStateDescription vmstate_x86_cpu = {
>          &vmstate_async_pf_msr,
>          &vmstate_pv_eoi_msr,
>          &vmstate_steal_time_msr,
> +        &vmstate_poll_control_msr,
>          &vmstate_fpop_ip_dp,
>          &vmstate_msr_tsc_adjust,
>          &vmstate_msr_tscdeadline,
> 

Queued, thanks.  Sorry for missing it until now.

Paolo