Re: [Qemu-devel] [PATCH v2 3/4] target-i386: Allow changing of Hypervisor CPUIDs.

[Marcelo Tosatti <mtosatti@redhat.com>]

The problem with integrating this is that it has little or 
no assurance from documentation. The Linux kernel source is a good
source, then say "accordingly to VMWare guest support code in version xyz"
in the changelog.

Also extracting this information in a text file (or comment in the code)
would be better than just adding code.

On Tue, Sep 11, 2012 at 10:07:46AM -0400, Don Slutz wrote:
> This is primarily done so that the guest will think it is running
> under vmware when hypervisor-vendor=vmware is specified as a
> property of a cpu.
> 
> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
> ---
>  target-i386/cpu.c |  214 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  target-i386/cpu.h |   21 +++++
>  target-i386/kvm.c |   33 +++++++--
>  3 files changed, 262 insertions(+), 6 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 5f9866a..9f1f390 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -1135,6 +1135,36 @@ static void x86_cpuid_set_model_id(Object *obj, const char *model_id,
>      }
>  }
>  
> +static void x86_cpuid_set_vmware_extra(Object *obj)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    if ((cpu->env.tsc_khz != 0) &&
> +        (cpu->env.cpuid_hv_level == CPUID_HV_LEVEL_VMARE_4) &&
> +        (cpu->env.cpuid_hv_vendor1 == CPUID_HV_VENDOR_VMWARE_1) &&
> +        (cpu->env.cpuid_hv_vendor2 == CPUID_HV_VENDOR_VMWARE_2) &&
> +        (cpu->env.cpuid_hv_vendor3 == CPUID_HV_VENDOR_VMWARE_3)) {
> +        const uint32_t apic_khz = 1000000L;
> +
> +        /*
> +         * From article.gmane.org/gmane.comp.emulators.kvm.devel/22643
> +         *
> +         *    Leaf 0x40000010, Timing Information.
> +         *
> +         *    VMware has defined the first generic leaf to provide timing
> +         *    information.  This leaf returns the current TSC frequency and
> +         *    current Bus frequency in kHz.
> +         *
> +         *    # EAX: (Virtual) TSC frequency in kHz.
> +         *    # EBX: (Virtual) Bus (local apic timer) frequency in kHz.
> +         *    # ECX, EDX: RESERVED (Per above, reserved fields are set to zero).
> +         */
> +        cpu->env.cpuid_hv_extra = 0x40000010;
> +        cpu->env.cpuid_hv_extra_a = (uint32_t)cpu->env.tsc_khz;
> +        cpu->env.cpuid_hv_extra_b = apic_khz;
> +    }
> +}

What happens in case you migrate the vmware guest to a host
with different frequency? How is that transmitted to the
vmware-guest-running-on-kvm ? Or is migration not supported?

> +static void x86_cpuid_set_hv_level(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +    uint32_t value;
> +
> +    visit_type_uint32(v, &value, name, errp);
> +    if (error_is_set(errp)) {
> +        return;
> +    }
> +
> +    if ((value != 0) && (value < 0x40000000)) {
> +        value += 0x40000000;
> +    }
> +    cpu->env.cpuid_hv_level = value;
> +}
> +
> +static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +    CPUX86State *env = &cpu->env;
> +    char *value;
> +    int i;
> +
> +    value = (char *)g_malloc(CPUID_VENDOR_SZ + 1);
> +    for (i = 0; i < 4; i++) {
> +        value[i + 0] = env->cpuid_hv_vendor1 >> (8 * i);
> +        value[i + 4] = env->cpuid_hv_vendor2 >> (8 * i);
> +        value[i + 8] = env->cpuid_hv_vendor3 >> (8 * i);
> +    }
> +    value[CPUID_VENDOR_SZ] = '\0';
> +
> +    /* Convert known names */
> +    if (!strcmp(value, CPUID_HV_VENDOR_VMWARE)) {
> +        if (env->cpuid_hv_level == CPUID_HV_LEVEL_VMARE_4) {
> +            pstrcpy(value, sizeof(value), "vmware4");
> +        } else if (env->cpuid_hv_level == CPUID_HV_LEVEL_VMARE_3) {
> +            pstrcpy(value, sizeof(value), "vmware3");
> +        }
> +    } else if (!strcmp(value, CPUID_HV_VENDOR_XEN) &&
> +               env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) {
> +        pstrcpy(value, sizeof(value), "xen");
> +    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) &&
> +               env->cpuid_hv_level == 0) {
> +        pstrcpy(value, sizeof(value), "kvm");
> +    }
> +    return value;
> +}
> +
> +static void x86_cpuid_set_hv_vendor(Object *obj, const char *value,
> +                                     Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +    CPUX86State *env = &cpu->env;
> +    int i;
> +    char adj_value[CPUID_VENDOR_SZ + 1];
> +
> +    memset(adj_value, 0, sizeof(adj_value));
> +
> +    /* Convert known names */
> +    if (!strcmp(value, "vmware") || !strcmp(value, "vmware4")) {
> +        if (env->cpuid_hv_level == 0) {
> +            env->cpuid_hv_level = CPUID_HV_LEVEL_VMARE_4;
> +        }
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_VMWARE);
> +    } else if (!strcmp(value, "vmware3")) {
> +        if (env->cpuid_hv_level == 0) {
> +            env->cpuid_hv_level = CPUID_HV_LEVEL_VMARE_3;
> +        }
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_VMWARE);
> +    } else if (!strcmp(value, "xen")) {
> +        if (env->cpuid_hv_level == 0) {
> +            env->cpuid_hv_level = CPUID_HV_LEVEL_XEN;
> +        }
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN);
> +    } else if (!strcmp(value, "kvm")) {
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
> +    } else {
> +        pstrcpy(adj_value, sizeof(adj_value), value);
> +    }
> +
> +    env->cpuid_hv_vendor1 = 0;
> +    env->cpuid_hv_vendor2 = 0;
> +    env->cpuid_hv_vendor3 = 0;
> +    for (i = 0; i < 4; i++) {
> +        env->cpuid_hv_vendor1 |= ((uint8_t)adj_value[i + 0]) << (8 * i);
> +        env->cpuid_hv_vendor2 |= ((uint8_t)adj_value[i + 4]) << (8 * i);
> +        env->cpuid_hv_vendor3 |= ((uint8_t)adj_value[i + 8]) << (8 * i);
> +    }
> +    x86_cpuid_set_vmware_extra(obj);
> +}
> +
> +static void x86_cpuid_get_hv_extra(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    visit_type_uint32(v, &cpu->env.cpuid_hv_extra, name, errp);
> +}
> +
> +static void x86_cpuid_set_hv_extra(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +    uint32_t value;
> +
> +    visit_type_uint32(v, &value, name, errp);
> +    if (error_is_set(errp)) {
> +        return;
> +    }
> +
> +    if ((value != 0) && (value < 0x40000000)) {
> +        value += 0x40000000;
> +    }
> +    cpu->env.cpuid_hv_extra = value;
> +}
> +
> +static void x86_cpuid_get_hv_extra_a(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_a, name, errp);
> +}
> +
> +static void x86_cpuid_set_hv_extra_a(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_a, name, errp);
> +}
> +
> +static void x86_cpuid_get_hv_extra_b(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_b, name, errp);
> +}
> +
> +static void x86_cpuid_set_hv_extra_b(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_b, name, errp);
>  }
>  
>  #if !defined(CONFIG_USER_ONLY)
> +static void x86_set_hyperv(Object *obj, Error **errp)
> +{
> +    X86CPU *cpu = X86_CPU(obj);
> +
> +    cpu->env.cpuid_hv_level = HYPERV_CPUID_MIN;
> +    x86_cpuid_set_hv_vendor(obj, "Microsoft Hv", errp);
> +}
> +
>  static void x86_get_hv_spinlocks(Object *obj, Visitor *v, void *opaque,
>                                   const char *name, Error **errp)
>  {
> @@ -1189,6 +1385,7 @@ static void x86_set_hv_spinlocks(Object *obj, Visitor *v, void *opaque,
>          return;
>      }
>      hyperv_set_spinlock_retries(value);
> +    x86_set_hyperv(obj, errp);
>  }
>  
>  static void x86_get_hv_relaxed(Object *obj, Visitor *v, void *opaque,
> @@ -1209,6 +1406,7 @@ static void x86_set_hv_relaxed(Object *obj, Visitor *v, void *opaque,
>          return;
>      }
>      hyperv_enable_relaxed_timing(value);
> +    x86_set_hyperv(obj, errp);
>  }

This seems unrelated to the rest of the patch?

>  static void x86_get_hv_vapic(Object *obj, Visitor *v, void *opaque,
> @@ -1229,6 +1427,7 @@ static void x86_set_hv_vapic(Object *obj, Visitor *v, void *opaque,
>          return;
>      }
>      hyperv_enable_vapic_recommended(value);
> +    x86_set_hyperv(obj, errp);
>  }
>  #endif
>  
> @@ -2061,6 +2260,21 @@ static void x86_cpu_initfn(Object *obj)
>      object_property_add(obj, "enforce", "bool",
>                          x86_cpuid_get_enforce,
>                          x86_cpuid_set_enforce, NULL, NULL, NULL);
> +    object_property_add(obj, "hypervisor-level", "int",
> +                        x86_cpuid_get_hv_level,
> +                        x86_cpuid_set_hv_level, NULL, NULL, NULL);
> +    object_property_add_str(obj, "hypervisor-vendor",
> +                            x86_cpuid_get_hv_vendor,
> +                            x86_cpuid_set_hv_vendor, NULL);
> +    object_property_add(obj, "hypervisor-extra", "int",
> +                        x86_cpuid_get_hv_extra,
> +                        x86_cpuid_set_hv_extra, NULL, NULL, NULL);
> +    object_property_add(obj, "hypervisor-extra-a", "int",
> +                        x86_cpuid_get_hv_extra_a,
> +                        x86_cpuid_set_hv_extra_a, NULL, NULL, NULL);
> +    object_property_add(obj, "hypervisor-extra-b", "int",
> +                        x86_cpuid_get_hv_extra_b,
> +                        x86_cpuid_set_hv_extra_b, NULL, NULL, NULL);
>  #if !defined(CONFIG_USER_ONLY)
>      object_property_add(obj, "hv_spinlocks", "int",
>                          x86_get_hv_spinlocks,
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 5265c5a..a2d3588 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -488,6 +488,18 @@
>  
>  #define CPUID_VENDOR_VIA   "CentaurHauls"
>  
> +#define CPUID_HV_VENDOR_VMWARE_1 0x61774d56 /* "VMwa" */
> +#define CPUID_HV_VENDOR_VMWARE_2 0x4d566572 /* "reVM" */
> +#define CPUID_HV_VENDOR_VMWARE_3 0x65726177 /* "ware" */
> +#define CPUID_HV_VENDOR_VMWARE "VMwareVMware"
> +#define CPUID_HV_LEVEL_VMARE_3 0x40000002
> +#define CPUID_HV_LEVEL_VMARE_4 0x40000010
> +
> +#define CPUID_HV_VENDOR_XEN "XenVMMXenVMM"
> +#define CPUID_HV_LEVEL_XEN  0x40000002
> +
> +#define CPUID_HV_VENDOR_KVM "KVMKVMKVM"
> +
>  #define CPUID_MWAIT_IBE     (1 << 1) /* Interrupts can exit capability */
>  #define CPUID_MWAIT_EMX     (1 << 0) /* enumeration supported */
>  
> @@ -782,6 +794,15 @@ typedef struct CPUX86State {
>      uint32_t cpuid_ext4_features;
>      /* Flags from CPUID[EAX=7,ECX=0].EBX */
>      uint32_t cpuid_7_0_ebx;
> +    /* Hypervisor CPUIDs */
> +    uint32_t cpuid_hv_level;
> +    uint32_t cpuid_hv_vendor1;
> +    uint32_t cpuid_hv_vendor2;
> +    uint32_t cpuid_hv_vendor3;
> +    /* VMware extra data */
> +    uint32_t cpuid_hv_extra;
> +    uint32_t cpuid_hv_extra_a;
> +    uint32_t cpuid_hv_extra_b;
>  
>      /* MTRRs */
>      uint64_t mtrr_fixed[11];
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 895d848..17c72bc 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -389,16 +389,18 @@ int kvm_arch_init_vcpu(CPUX86State *env)
>      c = &cpuid_data.entries[cpuid_i++];
>      memset(c, 0, sizeof(*c));
>      c->function = KVM_CPUID_SIGNATURE;
> -    if (!hyperv_enabled()) {
> +    if (env->cpuid_hv_level == 0) {
>          memcpy(signature, "KVMKVMKVM\0\0\0", 12);
>          c->eax = 0;
> +        c->ebx = signature[0];
> +        c->ecx = signature[1];
> +        c->edx = signature[2];
>      } else {
> -        memcpy(signature, "Microsoft Hv", 12);
> -        c->eax = HYPERV_CPUID_MIN;
> +        c->eax = env->cpuid_hv_level;
> +        c->ebx = env->cpuid_hv_vendor1;
> +        c->ecx = env->cpuid_hv_vendor2;
> +        c->edx = env->cpuid_hv_vendor3;
>      }
> -    c->ebx = signature[0];
> -    c->ecx = signature[1];
> -    c->edx = signature[2];
>  
>      c = &cpuid_data.entries[cpuid_i++];
>      memset(c, 0, sizeof(*c));
> @@ -452,6 +454,25 @@ int kvm_arch_init_vcpu(CPUX86State *env)
>          c->ebx = signature[0];
>          c->ecx = signature[1];
>          c->edx = signature[2];
> +    } else if (env->cpuid_hv_level > 0) {
> +        for (i = KVM_CPUID_FEATURES + 1; i <= env->cpuid_hv_level; i++) {
> +            c = &cpuid_data.entries[cpuid_i++];
> +            memset(c, 0, sizeof(*c));
> +            c->function = i;
> +            if (i == env->cpuid_hv_extra) {
> +                c->eax = env->cpuid_hv_extra_a;
> +                c->ebx = env->cpuid_hv_extra_b;
> +            }
> +        }
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = KVM_CPUID_SIGNATURE_NEXT;
> +        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> +        c->eax = 0;
> +        c->ebx = signature[0];
> +        c->ecx = signature[1];
> +        c->edx = signature[2];
>      }
>  
>      has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);


Its one big patch, better split in logically correlated patches
(with better changelog). This would help reviewers.