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Re: [Qemu-devel] [PATCH] i386/kvm: expose HV_CPUID_ENLIGHTMENT_INFO.EAX
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] i386/kvm: expose HV_CPUID_ENLIGHTMENT_INFO.EAX and HV_CPUID_NESTED_FEATURES.EAX as feature words |
Date: |
Thu, 29 Nov 2018 11:20:14 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 26/11/18 14:59, Vitaly Kuznetsov wrote:
> It was found that QMP users of QEMU (e.g. libvirt) may need
> HV_CPUID_ENLIGHTMENT_INFO.EAX/HV_CPUID_NESTED_FEATURES.EAX information. In
> particular, 'hv_tlbflush' and 'hv_evmcs' enlightenments are only exposed in
> HV_CPUID_ENLIGHTMENT_INFO.EAX.
>
> HV_CPUID_NESTED_FEATURES.EAX is exposed for two reasons: convenience
> (we don't need to export it from hyperv_handle_properties() and as
> future-proof for Enlightened MSR-Bitmap, PV EPT invalidation and
> direct virtual flush features.
>
> Signed-off-by: Vitaly Kuznetsov <address@hidden>
Can you add a comment to feature_word_info, explaining why the
feat_names are not set?
Thanks,
Paolo
> ---
> target/i386/cpu.c | 30 +++++++++++++++++
> target/i386/cpu.h | 2 ++
> target/i386/kvm.c | 85 +++++++++++++++++++++++++----------------------
> 3 files changed, 77 insertions(+), 40 deletions(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index f81d35e1f9..8306670e09 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -980,6 +980,36 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS]
> = {
> },
> .cpuid = { .eax = 0x40000003, .reg = R_EDX, },
> },
> + [FEAT_HV_RECOMM_EAX] = {
> + .type = CPUID_FEATURE_WORD,
> + .feat_names = {
> + NULL /* hv_recommend_pv_as_switch */,
> + NULL /* hv_recommend_pv_tlbflush_local */,
> + NULL /* hv_recommend_pv_tlbflush_remote */,
> + NULL /* hv_recommend_msr_apic_access */,
> + NULL /* hv_recommend_msr_reset */,
> + NULL /* hv_recommend_relaxed_timing */,
> + NULL /* hv_recommend_dma_remapping */,
> + NULL /* hv_recommend_int_remapping */,
> + NULL /* hv_recommend_x2apic_msrs */,
> + NULL /* hv_recommend_autoeoi_deprecation */,
> + NULL /* hv_recommend_pv_ipi */,
> + NULL /* hv_recommend_ex_hypercalls */,
> + NULL /* hv_hypervisor_is_nested */,
> + NULL /* hv_recommend_int_mbec */,
> + NULL /* hv_recommend_evmcs */,
> + NULL,
> + NULL, NULL, NULL, NULL,
> + NULL, NULL, NULL, NULL,
> + NULL, NULL, NULL, NULL,
> + NULL, NULL, NULL, NULL,
> + },
> + .cpuid = { .eax = 0x40000004, .reg = R_EAX, },
> + },
> + [FEAT_HV_NESTED_EAX] = {
> + .type = CPUID_FEATURE_WORD,
> + .cpuid = { .eax = 0x4000000A, .reg = R_EAX, },
> + },
> [FEAT_SVM] = {
> .type = CPUID_FEATURE_WORD,
> .feat_names = {
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 9c52d0cbeb..dd881510ac 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -497,6 +497,8 @@ typedef enum FeatureWord {
> FEAT_HYPERV_EAX, /* CPUID[4000_0003].EAX */
> FEAT_HYPERV_EBX, /* CPUID[4000_0003].EBX */
> FEAT_HYPERV_EDX, /* CPUID[4000_0003].EDX */
> + FEAT_HV_RECOMM_EAX, /* CPUID[4000_0004].EAX */
> + FEAT_HV_NESTED_EAX, /* CPUID[4000_000A].EAX */
> FEAT_SVM, /* CPUID[8000_000A].EDX */
> FEAT_XSAVE, /* CPUID[EAX=0xd,ECX=1].EAX */
> FEAT_6_EAX, /* CPUID[6].EAX */
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index f524e7d929..b4d2b40a40 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -797,6 +797,48 @@ static int hyperv_handle_properties(CPUState *cs)
> }
> env->features[FEAT_HYPERV_EAX] |= HV_SYNTIMERS_AVAILABLE;
> }
> + if (cpu->hyperv_relaxed_timing) {
> + env->features[FEAT_HV_RECOMM_EAX] |= HV_RELAXED_TIMING_RECOMMENDED;
> + }
> + if (cpu->hyperv_vapic) {
> + env->features[FEAT_HV_RECOMM_EAX] |= HV_APIC_ACCESS_RECOMMENDED;
> + }
> + if (cpu->hyperv_tlbflush) {
> + if (kvm_check_extension(cs->kvm_state,
> + KVM_CAP_HYPERV_TLBFLUSH) <= 0) {
> + fprintf(stderr, "Hyper-V TLB flush support "
> + "(requested by 'hv-tlbflush' cpu flag) "
> + " is not supported by kernel\n");
> + return -ENOSYS;
> + }
> + env->features[FEAT_HV_RECOMM_EAX] |= HV_REMOTE_TLB_FLUSH_RECOMMENDED;
> + env->features[FEAT_HV_RECOMM_EAX] |=
> HV_EX_PROCESSOR_MASKS_RECOMMENDED;
> + }
> + if (cpu->hyperv_ipi) {
> + if (kvm_check_extension(cs->kvm_state,
> + KVM_CAP_HYPERV_SEND_IPI) <= 0) {
> + fprintf(stderr, "Hyper-V IPI send support "
> + "(requested by 'hv-ipi' cpu flag) "
> + " is not supported by kernel\n");
> + return -ENOSYS;
> + }
> + env->features[FEAT_HV_RECOMM_EAX] |= HV_CLUSTER_IPI_RECOMMENDED;
> + env->features[FEAT_HV_RECOMM_EAX] |=
> HV_EX_PROCESSOR_MASKS_RECOMMENDED;
> + }
> + if (cpu->hyperv_evmcs) {
> + uint16_t evmcs_version;
> +
> + if (kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_ENLIGHTENED_VMCS, 0,
> + (uintptr_t)&evmcs_version)) {
> + fprintf(stderr, "Hyper-V Enlightened VMCS "
> + "(requested by 'hv-evmcs' cpu flag) "
> + "is not supported by kernel\n");
> + return -ENOSYS;
> + }
> + env->features[FEAT_HV_RECOMM_EAX] |= HV_ENLIGHTENED_VMCS_RECOMMENDED;
> + env->features[FEAT_HV_NESTED_EAX] = evmcs_version;
> + }
> +
> return 0;
> }
>
> @@ -869,7 +911,6 @@ int kvm_arch_init_vcpu(CPUState *cs)
> uint32_t unused;
> struct kvm_cpuid_entry2 *c;
> uint32_t signature[3];
> - uint16_t evmcs_version;
> int kvm_base = KVM_CPUID_SIGNATURE;
> int r;
> Error *local_err = NULL;
> @@ -944,44 +985,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
>
> c = &cpuid_data.entries[cpuid_i++];
> c->function = HV_CPUID_ENLIGHTMENT_INFO;
> - if (cpu->hyperv_relaxed_timing) {
> - c->eax |= HV_RELAXED_TIMING_RECOMMENDED;
> - }
> - if (cpu->hyperv_vapic) {
> - c->eax |= HV_APIC_ACCESS_RECOMMENDED;
> - }
> - if (cpu->hyperv_tlbflush) {
> - if (kvm_check_extension(cs->kvm_state,
> - KVM_CAP_HYPERV_TLBFLUSH) <= 0) {
> - fprintf(stderr, "Hyper-V TLB flush support "
> - "(requested by 'hv-tlbflush' cpu flag) "
> - " is not supported by kernel\n");
> - return -ENOSYS;
> - }
> - c->eax |= HV_REMOTE_TLB_FLUSH_RECOMMENDED;
> - c->eax |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
> - }
> - if (cpu->hyperv_ipi) {
> - if (kvm_check_extension(cs->kvm_state,
> - KVM_CAP_HYPERV_SEND_IPI) <= 0) {
> - fprintf(stderr, "Hyper-V IPI send support "
> - "(requested by 'hv-ipi' cpu flag) "
> - " is not supported by kernel\n");
> - return -ENOSYS;
> - }
> - c->eax |= HV_CLUSTER_IPI_RECOMMENDED;
> - c->eax |= HV_EX_PROCESSOR_MASKS_RECOMMENDED;
> - }
> - if (cpu->hyperv_evmcs) {
> - if (kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_ENLIGHTENED_VMCS, 0,
> - (uintptr_t)&evmcs_version)) {
> - fprintf(stderr, "Hyper-V Enlightened VMCS "
> - "(requested by 'hv-evmcs' cpu flag) "
> - "is not supported by kernel\n");
> - return -ENOSYS;
> - }
> - c->eax |= HV_ENLIGHTENED_VMCS_RECOMMENDED;
> - }
> +
> + c->eax = env->features[FEAT_HV_RECOMM_EAX];
> c->ebx = cpu->hyperv_spinlock_attempts;
>
> c = &cpuid_data.entries[cpuid_i++];
> @@ -1005,7 +1010,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>
> c = &cpuid_data.entries[cpuid_i++];
> c->function = HV_CPUID_NESTED_FEATURES;
> - c->eax = evmcs_version;
> + c->eax = env->features[FEAT_HV_NESTED_EAX];
> }
> }
>
>