Re: [Qemu-devel] [PATCH] qemu-kvm: Add CPUID support for VIA CPU

[Jan Kiszka]

Hi,

the subject's tag (qemu-kvm) is misleading. This is actually targeting
the uq/master patch queue, i.e. the upstream kvm staging area.

On 2011-05-05 05:03, address@hidden wrote:
> When KVM is running on VIA CPU with host cpu's model, the feautures of
> VIA CPU will be passed into kvm guest by calling the CPUID instruction
> for Centaur.
> 
> Signed-off-by: BrillyWu<address@hidden>
> Signed-off-by: KaryJin<address@hidden>
> ---
>  target-i386/cpu.h   |    7 +++++++
>  target-i386/cpuid.c |   48
> +++++++++++++++++++++++++++++++++++++++++++++++-

You patch is unfortunately line-wrapped.

>  target-i386/kvm.c   |   15 +++++++++++++++
>  3 files changed, 69 insertions(+), 1 deletion(-)
> 
> --- a/target-i386/cpu.h       2011-05-05 09:01:11.742328398 +0800
> +++ b/target-i386/cpu.h       2011-05-05 10:47:32.112329696 +0800
> @@ -441,6 +441,10 @@
>  #define CPUID_VENDOR_AMD_2   0x69746e65 /* "enti" */ 
>  #define CPUID_VENDOR_AMD_3   0x444d4163 /* "cAMD" */
>  
> +#define CPUID_VENDOR_VIA_1   0x746e6543 /* "Cent" */
> +#define CPUID_VENDOR_VIA_2   0x48727561 /* "aurH" */
> +#define CPUID_VENDOR_VIA_3   0x736c7561 /* "auls" */
> +
>  #define CPUID_MWAIT_IBE     (1 << 1) /* Interrupts can exit capability
> */
>  #define CPUID_MWAIT_EMX     (1 << 0) /* enumeration supported */
>  
> @@ -721,6 +725,9 @@ typedef struct CPUX86State {
>      uint32_t cpuid_ext3_features;
>      uint32_t cpuid_apic_id;
>      int cpuid_vendor_override;
> +    /*Store the results of Centaur's CPUID instructions*/

Please format comments like this /* comment text */, ie. with blanks
after/before the /* / */.

> +    uint32_t cpuid_xlevel2;
> +    uint32_t cpuid_ext4_features;
>  
>      /* MTRRs */
>      uint64_t mtrr_fixed[11];
> --- a/target-i386/cpuid.c     2011-05-05 09:01:05.352331142 +0800
> +++ b/target-i386/cpuid.c     2011-05-05 10:47:41.102330705 +0800
> @@ -230,6 +230,9 @@ typedef struct x86_def_t {
>      char model_id[48];
>      int vendor_override;
>      uint32_t flags;
> +    /*Store the results of Centaur's CPUID instructions*/
> +    uint32_t ext4_features;
> +    uint32_t xlevel2;
>  } x86_def_t;
>  
>  #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE) @@ -522,6
> +525,17 @@ static int cpu_x86_fill_host(x86_def_t *
>      cpu_x86_fill_model_id(x86_cpu_def->model_id);
>      x86_cpu_def->vendor_override = 0;
>  
> +    /* Call Centaur's CPUID instruction. */
> +    if (x86_cpu_def->vendor1 == CPUID_VENDOR_VIA_1 &&
> +     x86_cpu_def->vendor2 == CPUID_VENDOR_VIA_2 &&
> +     x86_cpu_def->vendor3 == CPUID_VENDOR_VIA_3) {
> +         host_cpuid(0xC0000000, 0, &eax, &ebx, &ecx, &edx);
> +         if (eax >= 0xC0000001) {
> +             x86_cpu_def->xlevel2 = eax; /*support VIA max extended
> level*/
> +             host_cpuid(0xC0000001, 0, &eax, &ebx, &ecx, &edx);
> +             x86_cpu_def->ext4_features = edx;
> +         }
> +    }
>  
>      /*
>       * Every SVM feature requires emulation support in KVM - so we
> can't just @@ -855,6 +869,8 @@ int cpu_x86_register (CPUX86State *env,
>      env->cpuid_xlevel = def->xlevel;
>      env->cpuid_kvm_features = def->kvm_features;
>      env->cpuid_svm_features = def->svm_features;
> +    env->cpuid_ext4_features = def->ext4_features;
> +    env->cpuid_xlevel2 = def->xlevel2;
>      if (!kvm_enabled()) {
>          env->cpuid_features &= TCG_FEATURES;
>          env->cpuid_ext_features &= TCG_EXT_FEATURES; @@ -1034,7
> +1050,15 @@ void cpu_x86_cpuid(CPUX86State *env, uin
>                     uint32_t *ecx, uint32_t *edx)  {
>      /* test if maximum index reached */
> -    if (index & 0x80000000) {
> +    if ((index & 0xC0000000) == 0xC0000000) {
> +     /* Handle the Centaur's CPUID instruction.*
> +     * If cpuid_xlevel2 is "0", then put into the*
> +     * default case. */
> +     if (env->cpuid_xlevel2 == 0)
> +         index = 0xF0000000;
> +     else if (index > env->cpuid_xlevel2)
> +         index = env->cpuid_xlevel2;

Please validate your patch before posting with scripts/checkpatch.pl.

> +    } else if (index & 0x80000000) {
>          if (index > env->cpuid_xlevel)
>              index = env->cpuid_level;
>      } else {
> @@ -1256,6 +1280,28 @@ void cpu_x86_cpuid(CPUX86State *env, uin
>               *edx = 0;
>       }
>          break;
> +    case 0xC0000000:
> +     *eax = env->cpuid_xlevel2;
> +     *ebx = 0;
> +     *ecx = 0;
> +     *edx = 0;
> +     break;
> +    case 0xC0000001:
> +     /* Support for VIA CPU's CPUID instruction */
> +     *eax = env->cpuid_version;
> +     *ebx = 0;
> +     *ecx = 0;
> +     *edx = env->cpuid_ext4_features;
> +     break;
> +    case 0xC0000002:
> +    case 0xC0000003:
> +    case 0xC0000004:
> +     /*Reserved for the future, and now filled with zero*/
> +     *eax = 0;
> +     *ebx = 0;
> +     *ecx = 0;
> +     *edx = 0;
> +     break;
>      default:
>          /* reserved values: zero */
>          *eax = 0;
> --- a/target-i386/kvm.c       2011-05-05 09:01:17.182326246 +0800
> +++ b/target-i386/kvm.c       2011-05-05 10:47:48.312331989 +0800
> @@ -496,6 +496,21 @@ int kvm_arch_init_vcpu(CPUState *env)
>          cpu_x86_cpuid(env, i, 0, &c->eax, &c->ebx, &c->ecx, &c->edx);
>      }
>  
> +    /* Call Centaur's CPUID instructions they are supported. */
> +    if (env->cpuid_xlevel2 > 0) {
> +     env->cpuid_ext4_features &=
> +             kvm_arch_get_supported_cpuid(env, 0xC0000001, 0, R_EDX);
> +     cpu_x86_cpuid(env, 0xC0000000, 0, &limit, &unused, &unused,
> &unused);
> +
> +     for (i = 0xC0000000; i <= limit; i++) {
> +         c = &cpuid_data.entries[cpuid_i++];
> +
> +         c->function = i;
> +         c->flags = 0;
> +         cpu_x86_cpuid(env, i, 0, &c->eax, &c->ebx, &c->ecx,
> &c->edx);
> +     }
> +    }
> +
>      cpuid_data.cpuid.nent = cpuid_i;
>  
>  #ifdef KVM_CAP_MCE

Thanks,
Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux