| Message ID | 20181019111432.5040-3-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i386/kvm: add support for Hyper-V Enlightened VMCS | expand |
On Fri, Oct 19, 2018 at 01:14:32PM +0200, Vitaly Kuznetsov wrote: > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -798,6 +798,7 @@ 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; > @@ -841,7 +842,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > memset(signature, 0, 12); > memcpy(signature, cpu->hyperv_vendor_id, len); > } > - c->eax = HV_CPUID_MIN; > + c->eax = cpu->hyperv_evmcs ? HV_CPUID_MIN_NESTED : HV_CPUID_MIN; I think these two aren't meant to be used on the hypervisor side. My understanding is that HV_CPUID_MIN is only there as a reminder that the real Hyper-V exposes at least that many hypervisor-specific leaves so the guest can rely on that. So I'd rather use directly HV_CPUID_IMPLEMENT_LIMITS : HV_CPUID_NESTED_FEATURES, and not introduce HV_CPUID_MIN_NESTED. Maybe better yet is to update this field with the maximum value while populating HV_* leaves: if (hyperv_enabled(cpu)) { uint32_t *cpuid_40000000_eax; c = &cpuid_data.entries[cpuid_i++]; c->function = HV_CPUID_VENDOR_AND_MAX_FUNCTIONS; cpuid_40000000_eax = &c->eax; *cpuid_40000000_eax = c->function; .... c = &cpuid_data.entries[cpuid_i++]; c->function = HV_CPUID_...; *cpuid_40000000_eax = max(*cpuid_40000000_eax, c->function); but I think it can be done later and doesn't need to hold this patch. Another question related to this: are the guests OK with leaves 0x40000006..0x40000009 missing? Thanks, Roman.
Roman Kagan <rkagan@virtuozzo.com> writes: > On Fri, Oct 19, 2018 at 01:14:32PM +0200, Vitaly Kuznetsov wrote: >> --- a/target/i386/kvm.c >> +++ b/target/i386/kvm.c >> @@ -798,6 +798,7 @@ 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; >> @@ -841,7 +842,7 @@ int kvm_arch_init_vcpu(CPUState *cs) >> memset(signature, 0, 12); >> memcpy(signature, cpu->hyperv_vendor_id, len); >> } >> - c->eax = HV_CPUID_MIN; >> + c->eax = cpu->hyperv_evmcs ? HV_CPUID_MIN_NESTED : HV_CPUID_MIN; > > > I think these two aren't meant to be used on the hypervisor side. My > understanding is that HV_CPUID_MIN is only there as a reminder that the > real Hyper-V exposes at least that many hypervisor-specific leaves so > the guest can rely on that. So I'd rather use directly > HV_CPUID_IMPLEMENT_LIMITS : HV_CPUID_NESTED_FEATURES, and not introduce > HV_CPUID_MIN_NESTED. Makes sense, will do v2. > Maybe better yet is to update this field with the > maximum value while populating HV_* leaves: > > if (hyperv_enabled(cpu)) { > uint32_t *cpuid_40000000_eax; > c = &cpuid_data.entries[cpuid_i++]; > c->function = HV_CPUID_VENDOR_AND_MAX_FUNCTIONS; > cpuid_40000000_eax = &c->eax; > *cpuid_40000000_eax = c->function; > > .... > > c = &cpuid_data.entries[cpuid_i++]; > c->function = HV_CPUID_...; > *cpuid_40000000_eax = max(*cpuid_40000000_eax, c->function); > > but I think it can be done later and doesn't need to hold this patch. > > Another question related to this: are the guests OK with leaves > 0x40000006..0x40000009 missing? They seem to be, however, after you've asked I'm leaning towards zeroing them 'just in case'.
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index c88876dfe3..5c0e84fb99 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -5564,6 +5564,7 @@ static Property x86_cpu_properties[] = { DEFINE_PROP_BOOL("hv-frequencies", X86CPU, hyperv_frequencies, false), DEFINE_PROP_BOOL("hv-reenlightenment", X86CPU, hyperv_reenlightenment, false), DEFINE_PROP_BOOL("hv-tlbflush", X86CPU, hyperv_tlbflush, false), + DEFINE_PROP_BOOL("hv-evmcs", X86CPU, hyperv_evmcs, false), DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true), DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false), DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true), diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 730c06f80a..013d953b57 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1382,6 +1382,7 @@ struct X86CPU { bool hyperv_frequencies; bool hyperv_reenlightenment; bool hyperv_tlbflush; + bool hyperv_evmcs; bool check_cpuid; bool enforce_cpuid; bool expose_kvm; diff --git a/target/i386/hyperv-proto.h b/target/i386/hyperv-proto.h index d6d5a79293..fcb0c416f8 100644 --- a/target/i386/hyperv-proto.h +++ b/target/i386/hyperv-proto.h @@ -18,7 +18,9 @@ #define HV_CPUID_FEATURES 0x40000003 #define HV_CPUID_ENLIGHTMENT_INFO 0x40000004 #define HV_CPUID_IMPLEMENT_LIMITS 0x40000005 +#define HV_CPUID_NESTED_FEATURES 0x4000000A #define HV_CPUID_MIN 0x40000005 +#define HV_CPUID_MIN_NESTED 0x4000000A #define HV_CPUID_MAX 0x4000ffff #define HV_HYPERVISOR_PRESENT_BIT 0x80000000 @@ -59,6 +61,7 @@ #define HV_SYSTEM_RESET_RECOMMENDED (1u << 4) #define HV_RELAXED_TIMING_RECOMMENDED (1u << 5) #define HV_EX_PROCESSOR_MASKS_RECOMMENDED (1u << 11) +#define HV_ENLIGHTENED_VMCS_RECOMMENDED (1u << 14) /* * Basic virtualized MSRs diff --git a/target/i386/kvm.c b/target/i386/kvm.c index a46ad102d8..8e383e7197 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -798,6 +798,7 @@ 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; @@ -841,7 +842,7 @@ int kvm_arch_init_vcpu(CPUState *cs) memset(signature, 0, 12); memcpy(signature, cpu->hyperv_vendor_id, len); } - c->eax = HV_CPUID_MIN; + c->eax = cpu->hyperv_evmcs ? HV_CPUID_MIN_NESTED : HV_CPUID_MIN; c->ebx = signature[0]; c->ecx = signature[1]; c->edx = signature[2]; @@ -888,7 +889,16 @@ int kvm_arch_init_vcpu(CPUState *cs) c->eax |= HV_REMOTE_TLB_FLUSH_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->ebx = cpu->hyperv_spinlock_attempts; c = &cpuid_data.entries[cpuid_i++]; @@ -899,6 +909,12 @@ int kvm_arch_init_vcpu(CPUState *cs) kvm_base = KVM_CPUID_SIGNATURE_NEXT; has_msr_hv_hypercall = true; + + if (cpu->hyperv_evmcs) { + c = &cpuid_data.entries[cpuid_i++]; + c->function = HV_CPUID_NESTED_FEATURES; + c->eax = evmcs_version; + } } if (cpu->expose_kvm) {
Adds a new CPU flag to enable the Enlightened VMCS KVM feature. QEMU enables KVM_CAP_HYPERV_ENLIGHTENED_VMCS and gets back the version to be advertised in lower 16 bits of CPUID.0x4000000A:EAX. Suggested-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- target/i386/cpu.c | 1 + target/i386/cpu.h | 1 + target/i386/hyperv-proto.h | 3 +++ target/i386/kvm.c | 20 ++++++++++++++++++-- 4 files changed, 23 insertions(+), 2 deletions(-)