[Qemu-devel] [PATCH v2 0/5] Enable TOPOEXT to support hyperthreading on AMD CPU

[Qemu-devel] [PATCH v2 0/5] Enable TOPOEXT to support hyperthreading on AMD CPU

[Babu Moger]

These series enable TOPOEXT feature on AMD CPU. These are required to support
hyperthreading on kvm guests. Addresses the issues reported by these bugs
https://bugzilla.redhat.com/show_bug.cgi?id=1481253
https://bugs.launchpad.net/qemu/+bug/1703506 

v2:
Fixed few more minor issues per Gary Hooks comments. Thank you Gary.
Removed the patch#1. We need to handle the instruction cache associativity 
seperately. It varies based on the cpu family. I will comeback to that later.
Added two more typo corrections in patch#1 and patch#5.

v1:
Stanislav Lanci posted few patches earlier. 
https://patchwork.kernel.org/patch/10040903/

Rebased his patches with few changes.
1. Spit the patches into two, separating cpuid functions 
   0x8000001D and 0x8000001E (Patch 2 and 3).
2. Removed the generic non-intel check and made a separate patch
   with some changes(Patch 5).
3. Fixed L3_N_SETS_AMD(from 4096 to 8192) based on CPUID_Fn8000001D_ECX_x03.

Added 2 more patches.
Patch 1. Fixes cache associativity.
Patch 4. Adds TOPOEXT feature on AMD EPYC CPU.


Babu Moger (3):
  target/i386: Fix a minor typo found while reviwing
  target/i386: Enable TOPOEXT feature on AMD EPYC CPU
  target/i386: Remove generic SMT thread check

Stanislav Lanci (2):
  target/i386: Populate AMD Processor Cache Information
  target/i386: Add support for CPUID_8000_001E for AMD

 linux-headers/asm-x86/kvm.h |   2 +-
 target/i386/cpu.c           | 104 ++++++++++++++++++++++++++++++++++++++++----
 target/i386/kvm.c           |  31 +++++++++++--
 3 files changed, 124 insertions(+), 13 deletions(-)

-- 
1.8.3.1

[Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo found while reviwing

[Babu Moger]

Changed KVM_CPUID_FLAG_SIGNIFCANT_INDEX to KVM_CPUID_FLAG_SIGNIFICANT_INDEX

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 linux-headers/asm-x86/kvm.h | 2 +-
 target/i386/kvm.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
index f3a9604..6aec661 100644
--- a/linux-headers/asm-x86/kvm.h
+++ b/linux-headers/asm-x86/kvm.h
@@ -220,7 +220,7 @@ struct kvm_cpuid_entry2 {
 	__u32 padding[3];
 };
 
-#define KVM_CPUID_FLAG_SIGNIFCANT_INDEX		(1 << 0)
+#define KVM_CPUID_FLAG_SIGNIFICANT_INDEX	(1 << 0)
 #define KVM_CPUID_FLAG_STATEFUL_FUNC		(1 << 1)
 #define KVM_CPUID_FLAG_STATE_READ_NEXT		(1 << 2)
 
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index ad4b159..85856b6 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -844,7 +844,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
                     break;
                 }
                 c->function = i;
-                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+                c->flags = KVM_CPUID_FLAG_SIGNIFICANT_INDEX;
                 c->index = j;
                 cpu_x86_cpuid(env, i, j, &c->eax, &c->ebx, &c->ecx, &c->edx);
 
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo found while reviwing

[Radim Krčmář]

2018-02-23 21:30-0500, Babu Moger:
> Changed KVM_CPUID_FLAG_SIGNIFCANT_INDEX to KVM_CPUID_FLAG_SIGNIFICANT_INDEX
> 
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  linux-headers/asm-x86/kvm.h | 2 +-
>  target/i386/kvm.c           | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
> index f3a9604..6aec661 100644
> --- a/linux-headers/asm-x86/kvm.h
> +++ b/linux-headers/asm-x86/kvm.h
> @@ -220,7 +220,7 @@ struct kvm_cpuid_entry2 {
>  	__u32 padding[3];
>  };
>  
> -#define KVM_CPUID_FLAG_SIGNIFCANT_INDEX		(1 << 0)

The typo is in the original kernel header and we periodically copy it
over with scripts/update-linux-headers.sh, so this change would only add
overhead in the long run.

I'd keep the typo.

(The alternative is to add KVM_CPUID_FLAG_SIGNIFICANT_INDEX to the linux
 header, so there would be both variants and use the correct one here.)

Thanks.

> +#define KVM_CPUID_FLAG_SIGNIFICANT_INDEX	(1 << 0)
>  #define KVM_CPUID_FLAG_STATEFUL_FUNC		(1 << 1)
>  #define KVM_CPUID_FLAG_STATE_READ_NEXT		(1 << 2)
>  
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index ad4b159..85856b6 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -844,7 +844,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>                      break;
>                  }
>                  c->function = i;
> -                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> +                c->flags = KVM_CPUID_FLAG_SIGNIFICANT_INDEX;
>                  c->index = j;
>                  cpu_x86_cpuid(env, i, j, &c->eax, &c->ebx, &c->ecx, &c->edx);
>  
> -- 
> 1.8.3.1
> 

Re: [Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo found while reviwing

[Eric Blake]

On 02/28/2018 11:38 AM, Radim Krčmář wrote:
> 2018-02-23 21:30-0500, Babu Moger:

In the subject line: s/reviwing/reviewing/  [It's never a good sign when 
a fix claiming to fix a typo introduces a typo ;) ]

Or go for a shorter subject:
  target/i386: Fix a minor typo

>> Changed KVM_CPUID_FLAG_SIGNIFCANT_INDEX to KVM_CPUID_FLAG_SIGNIFICANT_INDEX
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo found while reviwing

[Moger, Babu]

> -----Original Message-----
> From: Eric Blake [mailto:eblake@redhat.com]
> Sent: Wednesday, February 28, 2018 12:49 PM
> To: Radim Krčmář <rkrcmar@redhat.com>; Moger, Babu
> <Babu.Moger@amd.com>
> Cc: ehabkost@redhat.com; kvm@vger.kernel.org; mtosatti@redhat.com;
> Hook, Gary <Gary.Hook@amd.com>; qemu-devel@nongnu.org;
> pbonzini@redhat.com; pixo@polepetko.eu; rth@twiddle.net
> Subject: Re: [Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo
> found while reviwing
> 
> On 02/28/2018 11:38 AM, Radim Krčmář wrote:
> > 2018-02-23 21:30-0500, Babu Moger:
> 
> In the subject line: s/reviwing/reviewing/  [It's never a good sign when
> a fix claiming to fix a typo introduces a typo ;) ]

Good catch Eric. Sorry about that.  We don’t need this patch anymore. Thanks.

> 
> Or go for a shorter subject:
>   target/i386: Fix a minor typo
> 
> >> Changed KVM_CPUID_FLAG_SIGNIFCANT_INDEX to
> KVM_CPUID_FLAG_SIGNIFICANT_INDEX
> >>
> >> Signed-off-by: Babu Moger <babu.moger@amd.com>
> >> ---
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.           +1-919-301-3266
> Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH v2 1/5] target/i386: Fix a minor typo found while reviwing

[Moger, Babu]

> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Wednesday, February 28, 2018 11:38 AM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> Subject: Re: [PATCH v2 1/5] target/i386: Fix a minor typo found while
> reviwing
> 
> 2018-02-23 21:30-0500, Babu Moger:
> > Changed KVM_CPUID_FLAG_SIGNIFCANT_INDEX to
> KVM_CPUID_FLAG_SIGNIFICANT_INDEX
> >
> > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > ---
> >  linux-headers/asm-x86/kvm.h | 2 +-
> >  target/i386/kvm.c           | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
> > index f3a9604..6aec661 100644
> > --- a/linux-headers/asm-x86/kvm.h
> > +++ b/linux-headers/asm-x86/kvm.h
> > @@ -220,7 +220,7 @@ struct kvm_cpuid_entry2 {
> >  	__u32 padding[3];
> >  };
> >
> > -#define KVM_CPUID_FLAG_SIGNIFCANT_INDEX		(1 << 0)
> 
> The typo is in the original kernel header and we periodically copy it
> over with scripts/update-linux-headers.sh, so this change would only add
> overhead in the long run.

Yes. I see that now.

> 
> I'd keep the typo.

Sure. I will drop this patch. Let me not complicate things.

> 
> (The alternative is to add KVM_CPUID_FLAG_SIGNIFICANT_INDEX to the
> linux
>  header, so there would be both variants and use the correct one here.)
> 
> Thanks.
> 
> > +#define KVM_CPUID_FLAG_SIGNIFICANT_INDEX	(1 << 0)
> >  #define KVM_CPUID_FLAG_STATEFUL_FUNC		(1 << 1)
> >  #define KVM_CPUID_FLAG_STATE_READ_NEXT		(1 << 2)
> >
> > diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> > index ad4b159..85856b6 100644
> > --- a/target/i386/kvm.c
> > +++ b/target/i386/kvm.c
> > @@ -844,7 +844,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
> >                      break;
> >                  }
> >                  c->function = i;
> > -                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> > +                c->flags = KVM_CPUID_FLAG_SIGNIFICANT_INDEX;
> >                  c->index = j;
> >                  cpu_x86_cpuid(env, i, j, &c->eax, &c->ebx, &c->ecx, &c->edx);
> >
> > --
> > 1.8.3.1
> >

[Qemu-devel] [PATCH v2 2/5] target/i386: Populate AMD Processor Cache Information

[Babu Moger]

From: Stanislav Lanci <pixo@polepetko.eu>

Adds information about cache size and topology from cpuid 0x8000001D leaf
for different cache types on AMD processors.

Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 target/i386/cpu.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 target/i386/kvm.c | 29 ++++++++++++++++++---
 2 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index b5e431e..a5a480e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -118,6 +118,7 @@
 #define L1I_LINE_SIZE         64
 #define L1I_ASSOCIATIVITY      8
 #define L1I_SETS              64
+#define L1I_SETS_AMD         256
 #define L1I_PARTITIONS         1
 /* Size = LINE_SIZE*ASSOCIATIVITY*SETS*PARTITIONS = 32KiB */
 #define L1I_DESCRIPTOR CPUID_2_L1I_32KB_8WAY_64B
@@ -129,7 +130,9 @@
 /* Level 2 unified cache: */
 #define L2_LINE_SIZE          64
 #define L2_ASSOCIATIVITY      16
+#define L2_ASSOCIATIVITY_AMD   8
 #define L2_SETS             4096
+#define L2_SETS_AMD         1024
 #define L2_PARTITIONS          1
 /* Size = LINE_SIZE*ASSOCIATIVITY*SETS*PARTITIONS = 4MiB */
 /*FIXME: CPUID leaf 2 descriptor is inconsistent with CPUID leaf 4 */
@@ -146,6 +149,7 @@
 #define L3_N_LINE_SIZE         64
 #define L3_N_ASSOCIATIVITY     16
 #define L3_N_SETS           16384
+#define L3_N_SETS_AMD        8192
 #define L3_N_PARTITIONS         1
 #define L3_N_DESCRIPTOR CPUID_2_L3_16MB_16WAY_64B
 #define L3_N_LINES_PER_TAG      1
@@ -3590,6 +3594,78 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             *edx = 0;
         }
         break;
+    case 0x8000001D: /* AMD TOPOEXT cache info */
+        if (cpu->cache_info_passthrough) {
+            host_cpuid(index, count, eax, ebx, ecx, edx);
+            break;
+        } else if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
+            *eax = 0;
+            switch (count) {
+            case 0: /* L1 dcache info */
+                *eax |= CPUID_4_TYPE_DCACHE | \
+                        CPUID_4_LEVEL(1) | \
+                        CPUID_4_SELF_INIT_LEVEL | \
+                        ((cs->nr_threads - 1) << 14);
+                *ebx = (L1D_LINE_SIZE - 1) | \
+                       ((L1D_PARTITIONS - 1) << 12) | \
+                       ((L1D_ASSOCIATIVITY - 1) << 22);
+                *ecx = L1D_SETS - 1;
+                *edx = 0;
+                break;
+            case 1: /* L1 icache info */
+                *eax |= CPUID_4_TYPE_ICACHE | \
+                        CPUID_4_LEVEL(1) | \
+                        CPUID_4_SELF_INIT_LEVEL | \
+                        ((cs->nr_threads - 1) << 14);
+                *ebx = (L1I_LINE_SIZE - 1) | \
+                       ((L1I_PARTITIONS - 1) << 12) | \
+                       ((L1I_ASSOCIATIVITY_AMD - 1) << 22);
+                *ecx = L1I_SETS_AMD - 1;
+                *edx = 0;
+                break;
+            case 2: /* L2 cache info */
+                *eax |= CPUID_4_TYPE_UNIFIED | \
+                        CPUID_4_LEVEL(2) | \
+                        CPUID_4_SELF_INIT_LEVEL | \
+                        ((cs->nr_threads - 1) << 14);
+                *ebx = (L2_LINE_SIZE - 1) | \
+                       ((L2_PARTITIONS - 1) << 12) | \
+                       ((L2_ASSOCIATIVITY_AMD - 1) << 22);
+                *ecx = L2_SETS_AMD - 1;
+                *edx = CPUID_4_INCLUSIVE;
+                break;
+            case 3: /* L3 cache info */
+                if (!cpu->enable_l3_cache) {
+                    *eax = 0;
+                    *ebx = 0;
+                    *ecx = 0;
+                    *edx = 0;
+                    break;
+                }
+                *eax |= CPUID_4_TYPE_UNIFIED | \
+                        CPUID_4_LEVEL(3) | \
+                        CPUID_4_SELF_INIT_LEVEL | \
+                        ((cs->nr_cores * cs->nr_threads - 1) << 14);
+                *ebx = (L3_N_LINE_SIZE - 1) | \
+                       ((L3_N_PARTITIONS - 1) << 12) | \
+                       ((L3_N_ASSOCIATIVITY - 1) << 22);
+                *ecx = L3_N_SETS_AMD - 1;
+                *edx = CPUID_4_NO_INVD_SHARING;
+                break;
+            default: /* end of info */
+                *eax = 0;
+                *ebx = 0;
+                *ecx = 0;
+                *edx = 0;
+                break;
+            }
+        } else {
+            *eax = 0;
+            *ebx = 0;
+            *ecx = 0;
+            *edx = 0;
+        }
+        break;
     case 0xC0000000:
         *eax = env->cpuid_xlevel2;
         *ebx = 0;
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 85856b6..8adf7d1 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -909,9 +909,32 @@ int kvm_arch_init_vcpu(CPUState *cs)
         }
         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);
+        switch (i) {
+        case 0x8000001d:
+            /* Query for all AMD cache information leaves */
+            for (j = 0; ; j++) {
+                c->function = i;
+                c->flags = KVM_CPUID_FLAG_SIGNIFICANT_INDEX;
+                c->index = j;
+                cpu_x86_cpuid(env, i, j, &c->eax, &c->ebx, &c->ecx, &c->edx);
+
+                if (c->eax == 0) {
+                    break;
+                }
+                if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
+                    fprintf(stderr, "cpuid_data is full, no space for "
+                            "cpuid(eax:0x%x,ecx:0x%x)\n", i, j);
+                    abort();
+                }
+                c = &cpuid_data.entries[cpuid_i++];
+            }
+            break;
+        default:
+            c->function = i;
+            c->flags = 0;
+            cpu_x86_cpuid(env, i, 0, &c->eax, &c->ebx, &c->ecx, &c->edx);
+            break;
+        }
     }
 
     /* Call Centaur's CPUID instructions they are supported. */
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH v2 2/5] target/i386: Populate AMD Processor Cache Information

[Radim Krčmář]

2018-02-23 21:30-0500, Babu Moger:
> From: Stanislav Lanci <pixo@polepetko.eu>
> 
> Adds information about cache size and topology from cpuid 0x8000001D leaf
> for different cache types on AMD processors.
> 
> Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> @@ -3590,6 +3594,78 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
>              *edx = 0;
>          }
>          break;
> +    case 0x8000001D: /* AMD TOPOEXT cache info */
> +        if (cpu->cache_info_passthrough) {
> +            host_cpuid(index, count, eax, ebx, ecx, edx);
> +            break;
> +        } else if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
> +            *eax = 0;
> +            switch (count) {
> +            case 0: /* L1 dcache info */
> +                *eax |= CPUID_4_TYPE_DCACHE | \
> +                        CPUID_4_LEVEL(1) | \
> +                        CPUID_4_SELF_INIT_LEVEL | \
> +                        ((cs->nr_threads - 1) << 14);

CPUID_4 uses the same format even for bits 25-14, so this would look
better with a macro.

> +                *ebx = (L1D_LINE_SIZE - 1) | \
> +                       ((L1D_PARTITIONS - 1) << 12) | \
> +                       ((L1D_ASSOCIATIVITY - 1) << 22);
> +                *ecx = L1D_SETS - 1;

These numbers seem to have the same meaning as CPUID 4, but have
conflicting values.

I think we should not expose CPUID 4 with AMD CPUs or at least when they
have CPUID_EXT3_TOPOEXT (the latter is easier wrt. compatibility).

> +                *edx = 0;
> +                break;
> +            case 1: /* L1 icache info */
> +                *eax |= CPUID_4_TYPE_ICACHE | \
> +                        CPUID_4_LEVEL(1) | \
> +                        CPUID_4_SELF_INIT_LEVEL | \
> +                        ((cs->nr_threads - 1) << 14);
> +                *ebx = (L1I_LINE_SIZE - 1) | \
> +                       ((L1I_PARTITIONS - 1) << 12) | \
> +                       ((L1I_ASSOCIATIVITY_AMD - 1) << 22);
> +                *ecx = L1I_SETS_AMD - 1;
> +                *edx = 0;
> +                break;
> +            case 2: /* L2 cache info */
> +                *eax |= CPUID_4_TYPE_UNIFIED | \
> +                        CPUID_4_LEVEL(2) | \
> +                        CPUID_4_SELF_INIT_LEVEL | \
> +                        ((cs->nr_threads - 1) << 14);
> +                *ebx = (L2_LINE_SIZE - 1) | \
> +                       ((L2_PARTITIONS - 1) << 12) | \
> +                       ((L2_ASSOCIATIVITY_AMD - 1) << 22);
> +                *ecx = L2_SETS_AMD - 1;
> +                *edx = CPUID_4_INCLUSIVE;
> +                break;
> +            case 3: /* L3 cache info */
> +                if (!cpu->enable_l3_cache) {
> +                    *eax = 0;
> +                    *ebx = 0;
> +                    *ecx = 0;
> +                    *edx = 0;
> +                    break;
> +                }
> +                *eax |= CPUID_4_TYPE_UNIFIED | \
> +                        CPUID_4_LEVEL(3) | \
> +                        CPUID_4_SELF_INIT_LEVEL | \
> +                        ((cs->nr_cores * cs->nr_threads - 1) << 14);

This number seems to be the only difference that isn't just a difference
constant.  It tempts me to merge the cases for 4 and 0x8000001D as it
seems that vendors try to be compatible.

> +                *ebx = (L3_N_LINE_SIZE - 1) | \
> +                       ((L3_N_PARTITIONS - 1) << 12) | \
> +                       ((L3_N_ASSOCIATIVITY - 1) << 22);
> +                *ecx = L3_N_SETS_AMD - 1;
> +                *edx = CPUID_4_NO_INVD_SHARING;
> +                break;
> +            default: /* end of info */
> +                *eax = 0;
> +                *ebx = 0;
> +                *ecx = 0;
> +                *edx = 0;
> +                break;
> +            }
> +        } else {
> +            *eax = 0;
> +            *ebx = 0;
> +            *ecx = 0;
> +            *edx = 0;
> +        }
> +        break;
>      case 0xC0000000:
>          *eax = env->cpuid_xlevel2;
>          *ebx = 0;

The numbers looks like real hardware,

thanks.

Re: [Qemu-devel] [PATCH v2 2/5] target/i386: Populate AMD Processor Cache Information

[Moger, Babu]

Radim, Thanks for your comments. I am working on the changes.
But, I need few clarifications on your comments. Please see inline. 

> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Wednesday, February 28, 2018 12:09 PM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> Subject: Re: [PATCH v2 2/5] target/i386: Populate AMD Processor Cache
> Information
> 
> 2018-02-23 21:30-0500, Babu Moger:
> > From: Stanislav Lanci <pixo@polepetko.eu>
> >
> > Adds information about cache size and topology from cpuid 0x8000001D
> leaf
> > for different cache types on AMD processors.
> >
> > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > ---
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > @@ -3590,6 +3594,78 @@ void cpu_x86_cpuid(CPUX86State *env,
> uint32_t index, uint32_t count,
> >              *edx = 0;
> >          }
> >          break;
> > +    case 0x8000001D: /* AMD TOPOEXT cache info */
> > +        if (cpu->cache_info_passthrough) {
> > +            host_cpuid(index, count, eax, ebx, ecx, edx);
> > +            break;
> > +        } else if (env->features[FEAT_8000_0001_ECX] &
> CPUID_EXT3_TOPOEXT) {
> > +            *eax = 0;
> > +            switch (count) {
> > +            case 0: /* L1 dcache info */
> > +                *eax |= CPUID_4_TYPE_DCACHE | \
> > +                        CPUID_4_LEVEL(1) | \
> > +                        CPUID_4_SELF_INIT_LEVEL | \
> > +                        ((cs->nr_threads - 1) << 14);
> 
> CPUID_4 uses the same format even for bits 25-14, so this would look
> better with a macro.

Yes. We can do that. 

> 
> > +                *ebx = (L1D_LINE_SIZE - 1) | \
> > +                       ((L1D_PARTITIONS - 1) << 12) | \
> > +                       ((L1D_ASSOCIATIVITY - 1) << 22);
> > +                *ecx = L1D_SETS - 1;
> 
> These numbers seem to have the same meaning as CPUID 4, but have
> conflicting values.

I am not sure about conflicting values. Looking at the specs(page 78 CPUID_Fn8000001D_EBX_x00)
 https://support.amd.com/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf
 It looks correct to me.

> 
> I think we should not expose CPUID 4 with AMD CPUs or at least when they
> have CPUID_EXT3_TOPOEXT (the latter is easier wrt. compatibility).

Can you please elaborate on these comments? 
Did you mean we should remove the check CPUID_EXT3_TOPOEXT and remove all CPUID 4 references? 

> 
> > +                *edx = 0;
> > +                break;
> > +            case 1: /* L1 icache info */
> > +                *eax |= CPUID_4_TYPE_ICACHE | \
> > +                        CPUID_4_LEVEL(1) | \
> > +                        CPUID_4_SELF_INIT_LEVEL | \
> > +                        ((cs->nr_threads - 1) << 14);
> > +                *ebx = (L1I_LINE_SIZE - 1) | \
> > +                       ((L1I_PARTITIONS - 1) << 12) | \
> > +                       ((L1I_ASSOCIATIVITY_AMD - 1) << 22);
> > +                *ecx = L1I_SETS_AMD - 1;
> > +                *edx = 0;
> > +                break;
> > +            case 2: /* L2 cache info */
> > +                *eax |= CPUID_4_TYPE_UNIFIED | \
> > +                        CPUID_4_LEVEL(2) | \
> > +                        CPUID_4_SELF_INIT_LEVEL | \
> > +                        ((cs->nr_threads - 1) << 14);
> > +                *ebx = (L2_LINE_SIZE - 1) | \
> > +                       ((L2_PARTITIONS - 1) << 12) | \
> > +                       ((L2_ASSOCIATIVITY_AMD - 1) << 22);
> > +                *ecx = L2_SETS_AMD - 1;
> > +                *edx = CPUID_4_INCLUSIVE;
> > +                break;
> > +            case 3: /* L3 cache info */
> > +                if (!cpu->enable_l3_cache) {
> > +                    *eax = 0;
> > +                    *ebx = 0;
> > +                    *ecx = 0;
> > +                    *edx = 0;
> > +                    break;
> > +                }
> > +                *eax |= CPUID_4_TYPE_UNIFIED | \
> > +                        CPUID_4_LEVEL(3) | \
> > +                        CPUID_4_SELF_INIT_LEVEL | \
> > +                        ((cs->nr_cores * cs->nr_threads - 1) << 14);
> 
> This number seems to be the only difference that isn't just a difference
> constant.  It tempts me to merge the cases for 4 and 0x8000001D as it
> seems that vendors try to be compatible.

Yes. We could merge cases for 4 and 0x8000001D.

> 
> > +                *ebx = (L3_N_LINE_SIZE - 1) | \
> > +                       ((L3_N_PARTITIONS - 1) << 12) | \
> > +                       ((L3_N_ASSOCIATIVITY - 1) << 22);
> > +                *ecx = L3_N_SETS_AMD - 1;
> > +                *edx = CPUID_4_NO_INVD_SHARING;
> > +                break;
> > +            default: /* end of info */
> > +                *eax = 0;
> > +                *ebx = 0;
> > +                *ecx = 0;
> > +                *edx = 0;
> > +                break;
> > +            }
> > +        } else {
> > +            *eax = 0;
> > +            *ebx = 0;
> > +            *ecx = 0;
> > +            *edx = 0;
> > +        }
> > +        break;
> >      case 0xC0000000:
> >          *eax = env->cpuid_xlevel2;
> >          *ebx = 0;
> 
> The numbers looks like real hardware,

Do you want me to change anything here? 

> 
> thanks.

Re: [Qemu-devel] [PATCH v2 2/5] target/i386: Populate AMD Processor Cache Information

[Radim Krčmář]

2018-03-01 15:55+0000, Moger, Babu:
> Radim, Thanks for your comments. I am working on the changes.
> But, I need few clarifications on your comments. Please see inline. 
> 
> > -----Original Message-----
> > From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> > Sent: Wednesday, February 28, 2018 12:09 PM
> > To: Moger, Babu <Babu.Moger@amd.com>
> > Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> > mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> > pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> > Subject: Re: [PATCH v2 2/5] target/i386: Populate AMD Processor Cache
> > Information
> > 
> > 2018-02-23 21:30-0500, Babu Moger:
> > > From: Stanislav Lanci <pixo@polepetko.eu>
> > >
> > > Adds information about cache size and topology from cpuid 0x8000001D
> > leaf
> > > for different cache types on AMD processors.
> > >
> > > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > > ---
> > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > > @@ -3590,6 +3594,78 @@ void cpu_x86_cpuid(CPUX86State *env,
> > > +                *ebx = (L1D_LINE_SIZE - 1) | \
> > > +                       ((L1D_PARTITIONS - 1) << 12) | \
> > > +                       ((L1D_ASSOCIATIVITY - 1) << 22);
> > > +                *ecx = L1D_SETS - 1;
> > 
> > These numbers seem to have the same meaning as CPUID 4, but have
> > conflicting values.
> 
> I am not sure about conflicting values. Looking at the specs(page 78 CPUID_Fn8000001D_EBX_x00)
>  https://support.amd.com/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf
>  It looks correct to me.

I agree.  My comment is misplaced -- it should have been under the place
that uses *_AMD macros.

I wanted to point out that CPUID in QEMU is very Intel-focused and
always contains CPUID leaf 4, which has fields of the very same meaning,
but with different values.

> > I think we should not expose CPUID 4 with AMD CPUs or at least when they
> > have CPUID_EXT3_TOPOEXT (the latter is easier wrt. compatibility).
> 
> Can you please elaborate on these comments? 
> Did you mean we should remove the check CPUID_EXT3_TOPOEXT and remove all CPUID 4 references? 

CPUID 4 should have never been present when emulating AMD CPUs, but it's
worse now that the numbers are conflicting.

I meant to hide CPUID 4 for all AMD CPUs on future machine types, or at
least when CPUID_EXT3_TOPOEXT is enabled.

Keeping the current logic not a big problem as CPUID 4 should never be
used by operating systems on AMD nor trusted inside a VM.  Bringing the
emulation closer to real state would be nice, but this can definitely be
done later (aka never).

> > The numbers looks like real hardware,
> 
> Do you want me to change anything here?

No, I was just commending,

thanks.

Re: [Qemu-devel] [PATCH v2 2/5] target/i386: Populate AMD Processor Cache Information

[Moger, Babu]

> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Thursday, March 1, 2018 1:56 PM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> Subject: Re: [PATCH v2 2/5] target/i386: Populate AMD Processor Cache
> Information
> 
> 2018-03-01 15:55+0000, Moger, Babu:
> > Radim, Thanks for your comments. I am working on the changes.
> > But, I need few clarifications on your comments. Please see inline.
> >
> > > -----Original Message-----
> > > From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> > > Sent: Wednesday, February 28, 2018 12:09 PM
> > > To: Moger, Babu <Babu.Moger@amd.com>
> > > Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> > > mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> > > pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> > > Subject: Re: [PATCH v2 2/5] target/i386: Populate AMD Processor Cache
> > > Information
> > >
> > > 2018-02-23 21:30-0500, Babu Moger:
> > > > From: Stanislav Lanci <pixo@polepetko.eu>
> > > >
> > > > Adds information about cache size and topology from cpuid 0x8000001D
> > > leaf
> > > > for different cache types on AMD processors.
> > > >
> > > > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > > > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > > > ---
> > > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > > > @@ -3590,6 +3594,78 @@ void cpu_x86_cpuid(CPUX86State *env,
> > > > +                *ebx = (L1D_LINE_SIZE - 1) | \
> > > > +                       ((L1D_PARTITIONS - 1) << 12) | \
> > > > +                       ((L1D_ASSOCIATIVITY - 1) << 22);
> > > > +                *ecx = L1D_SETS - 1;
> > >
> > > These numbers seem to have the same meaning as CPUID 4, but have
> > > conflicting values.
> >
> > I am not sure about conflicting values. Looking at the specs(page 78
> CPUID_Fn8000001D_EBX_x00)
> >
> https://support.amd.com/TechDocs/54945_PPR_Family_17h_Models_00h-
> 0Fh.pdf
> >  It looks correct to me.
> 
> I agree.  My comment is misplaced -- it should have been under the place
> that uses *_AMD macros.
> 
> I wanted to point out that CPUID in QEMU is very Intel-focused and
> always contains CPUID leaf 4, which has fields of the very same meaning,
> but with different values.
> 
> > > I think we should not expose CPUID 4 with AMD CPUs or at least when
> they
> > > have CPUID_EXT3_TOPOEXT (the latter is easier wrt. compatibility).
> >
> > Can you please elaborate on these comments?
> > Did you mean we should remove the check CPUID_EXT3_TOPOEXT and
> remove all CPUID 4 references?
> 
> CPUID 4 should have never been present when emulating AMD CPUs, but it's
> worse now that the numbers are conflicting.
> 
> I meant to hide CPUID 4 for all AMD CPUs on future machine types, or at
> least when CPUID_EXT3_TOPOEXT is enabled.

Sorry, I think I created some confusion here by using CPUID 4 definitions which are
mostly for intel.  Let me rework on this. I will repost the patches.  Thanks for the
feedback.

> 
> Keeping the current logic not a big problem as CPUID 4 should never be
> used by operating systems on AMD nor trusted inside a VM.  Bringing the
> emulation closer to real state would be nice, but this can definitely be
> done later (aka never).
> 
> > > The numbers looks like real hardware,
> >
> > Do you want me to change anything here?
> 
> No, I was just commending,
> 
> thanks.

[Qemu-devel] [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E for AMD

[Babu Moger]

From: Stanislav Lanci <pixo@polepetko.eu>

Populate threads/core_id/apic_ids/socket_id when CPUID_EXT3_TOPOEXT
feature is supported. This is required to support hyperthreading
feature on AMD CPUS. These are supported via CPUID_8000_001E extended
functions.

Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 target/i386/cpu.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index a5a480e..191e850 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -3666,6 +3666,14 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             *edx = 0;
         }
         break;
+    case 0x8000001E:
+        if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
+            *eax = cpu->apic_id;
+            *ebx = (cs->nr_threads - 1) << 8 | cpu->core_id;
+            *ecx = cpu->socket_id;
+            *edx = 0;
+        }
+        break;
     case 0xC0000000:
         *eax = env->cpuid_xlevel2;
         *ebx = 0;
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E for AMD

[Radim Krčmář]

2018-02-23 21:30-0500, Babu Moger:
> From: Stanislav Lanci <pixo@polepetko.eu>
> 
> Populate threads/core_id/apic_ids/socket_id when CPUID_EXT3_TOPOEXT
> feature is supported. This is required to support hyperthreading
> feature on AMD CPUS. These are supported via CPUID_8000_001E extended
> functions.
> 
> Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
>  target/i386/cpu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index a5a480e..191e850 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -3666,6 +3666,14 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
>              *edx = 0;
>          }
>          break;
> +    case 0x8000001E:
> +        if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
> +            *eax = cpu->apic_id;
> +            *ebx = (cs->nr_threads - 1) << 8 | cpu->core_id;

Do we somewhere assert that AMD cannot have cpu->core_id > 255?
(qemu does allow weird configurations.)

Thanks.

> +            *ecx = cpu->socket_id;
> +            *edx = 0;
> +        }
> +        break;
>      case 0xC0000000:
>          *eax = env->cpuid_xlevel2;
>          *ebx = 0;
> -- 
> 1.8.3.1
> 

Re: [Qemu-devel] [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E for AMD

[Moger, Babu]

> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Wednesday, February 28, 2018 12:24 PM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> Subject: Re: [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E
> for AMD
> 
> 2018-02-23 21:30-0500, Babu Moger:
> > From: Stanislav Lanci <pixo@polepetko.eu>
> >
> > Populate threads/core_id/apic_ids/socket_id when CPUID_EXT3_TOPOEXT
> > feature is supported. This is required to support hyperthreading
> > feature on AMD CPUS. These are supported via CPUID_8000_001E
> extended
> > functions.
> >
> > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > ---
> >  target/i386/cpu.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index a5a480e..191e850 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -3666,6 +3666,14 @@ void cpu_x86_cpuid(CPUX86State *env,
> uint32_t index, uint32_t count,
> >              *edx = 0;
> >          }
> >          break;
> > +    case 0x8000001E:
> > +        if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
> > +            *eax = cpu->apic_id;
> > +            *ebx = (cs->nr_threads - 1) << 8 | cpu->core_id;
> 
> Do we somewhere assert that AMD cannot have cpu->core_id > 255?
> (qemu does allow weird configurations.)

I don't see specific assert on core_id.   But, I see that qemu does not allow nr_cores more than 255.
Also I see that core_id is iterated based on nr_cores.  If you strongly believe we need to add assert here, I will add it. 
Let me know.
 
> Thanks.
> 
> > +            *ecx = cpu->socket_id;
> > +            *edx = 0;
> > +        }
> > +        break;
> >      case 0xC0000000:
> >          *eax = env->cpuid_xlevel2;
> >          *ebx = 0;
> > --
> > 1.8.3.1
> >

Re: [Qemu-devel] [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E for AMD

[Radim Krčmář]

2018-02-28 22:18+0000, Moger, Babu:
> > -----Original Message-----
> > From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> > Sent: Wednesday, February 28, 2018 12:24 PM
> > To: Moger, Babu <Babu.Moger@amd.com>
> > Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> > mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> > pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> > Subject: Re: [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E
> > for AMD
> > 
> > 2018-02-23 21:30-0500, Babu Moger:
> > > From: Stanislav Lanci <pixo@polepetko.eu>
> > >
> > > Populate threads/core_id/apic_ids/socket_id when CPUID_EXT3_TOPOEXT
> > > feature is supported. This is required to support hyperthreading
> > > feature on AMD CPUS. These are supported via CPUID_8000_001E
> > extended
> > > functions.
> > >
> > > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > > ---
> > >  target/i386/cpu.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > > index a5a480e..191e850 100644
> > > --- a/target/i386/cpu.c
> > > +++ b/target/i386/cpu.c
> > > @@ -3666,6 +3666,14 @@ void cpu_x86_cpuid(CPUX86State *env,
> > uint32_t index, uint32_t count,
> > >              *edx = 0;
> > >          }
> > >          break;
> > > +    case 0x8000001E:
> > > +        if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
> > > +            *eax = cpu->apic_id;
> > > +            *ebx = (cs->nr_threads - 1) << 8 | cpu->core_id;
> > 
> > Do we somewhere assert that AMD cannot have cpu->core_id > 255?
> > (qemu does allow weird configurations.)
> 
> I don't see specific assert on core_id.   But, I see that qemu does not allow nr_cores more than 255.
> Also I see that core_id is iterated based on nr_cores.  If you strongly believe we need to add assert here, I will add it. 
> Let me know.

A user can emulate AMD with x2apic and intel-iommu to allow more than
255 vcpus and all of them can be a separate core (or its own socket),
which would overflow this (or the next counter).

Forbidding that crazy configuration may be preferable, but an assert
won't hurt now,

thanks.

> > Thanks.
> > 
> > > +            *ecx = cpu->socket_id;
> > > +            *edx = 0;
> > > +        }
> > > +        break;
> > >      case 0xC0000000:
> > >          *eax = env->cpuid_xlevel2;
> > >          *ebx = 0;
> > > --
> > > 1.8.3.1
> > >

Re: [Qemu-devel] [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E for AMD

[Moger, Babu]

> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Thursday, March 1, 2018 1:57 PM
> To: Moger, Babu <Babu.Moger@amd.com>
> Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> Subject: Re: [PATCH v2 3/5] target/i386: Add support for CPUID_8000_001E
> for AMD
> 
> 2018-02-28 22:18+0000, Moger, Babu:
> > > -----Original Message-----
> > > From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> > > Sent: Wednesday, February 28, 2018 12:24 PM
> > > To: Moger, Babu <Babu.Moger@amd.com>
> > > Cc: pbonzini@redhat.com; rth@twiddle.net; ehabkost@redhat.com;
> > > mtosatti@redhat.com; qemu-devel@nongnu.org; kvm@vger.kernel.org;
> > > pixo@polepetko.eu; Hook, Gary <Gary.Hook@amd.com>
> > > Subject: Re: [PATCH v2 3/5] target/i386: Add support for
> CPUID_8000_001E
> > > for AMD
> > >
> > > 2018-02-23 21:30-0500, Babu Moger:
> > > > From: Stanislav Lanci <pixo@polepetko.eu>
> > > >
> > > > Populate threads/core_id/apic_ids/socket_id when
> CPUID_EXT3_TOPOEXT
> > > > feature is supported. This is required to support hyperthreading
> > > > feature on AMD CPUS. These are supported via CPUID_8000_001E
> > > extended
> > > > functions.
> > > >
> > > > Signed-off-by: Stanislav Lanci <pixo@polepetko.eu>
> > > > Signed-off-by: Babu Moger <babu.moger@amd.com>
> > > > ---
> > > >  target/i386/cpu.c | 8 ++++++++
> > > >  1 file changed, 8 insertions(+)
> > > >
> > > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > > > index a5a480e..191e850 100644
> > > > --- a/target/i386/cpu.c
> > > > +++ b/target/i386/cpu.c
> > > > @@ -3666,6 +3666,14 @@ void cpu_x86_cpuid(CPUX86State *env,
> > > uint32_t index, uint32_t count,
> > > >              *edx = 0;
> > > >          }
> > > >          break;
> > > > +    case 0x8000001E:
> > > > +        if (env->features[FEAT_8000_0001_ECX] &
> CPUID_EXT3_TOPOEXT) {
> > > > +            *eax = cpu->apic_id;
> > > > +            *ebx = (cs->nr_threads - 1) << 8 | cpu->core_id;
> > >
> > > Do we somewhere assert that AMD cannot have cpu->core_id > 255?
> > > (qemu does allow weird configurations.)
> >
> > I don't see specific assert on core_id.   But, I see that qemu does not allow
> nr_cores more than 255.
> > Also I see that core_id is iterated based on nr_cores.  If you strongly
> believe we need to add assert here, I will add it.
> > Let me know.
> 
> A user can emulate AMD with x2apic and intel-iommu to allow more than
> 255 vcpus and all of them can be a separate core (or its own socket),
> which would overflow this (or the next counter).
> 
> Forbidding that crazy configuration may be preferable, but an assert
> won't hurt now,

Ok. Sure. Will add assert.

> 
> thanks.
> 
> > > Thanks.
> > >
> > > > +            *ecx = cpu->socket_id;
> > > > +            *edx = 0;
> > > > +        }
> > > > +        break;
> > > >      case 0xC0000000:
> > > >          *eax = env->cpuid_xlevel2;
> > > >          *ebx = 0;
> > > > --
> > > > 1.8.3.1
> > > >
> 

[Qemu-devel] [PATCH v2 4/5] target/i386: Enable TOPOEXT feature on AMD EPYC CPU

[Babu Moger]

Enable TOPOEXT feature on EPYC CPU. This is required to support
hyperthreading on VM guests. Also extend xlevel to 0x8000001E.
These are supported via CPUID_8000_001E extended functions.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 target/i386/cpu.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 191e850..6d06637 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1955,7 +1955,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_OSVW | CPUID_EXT3_3DNOWPREFETCH |
             CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM |
-            CPUID_EXT3_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM,
+            CPUID_EXT3_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM |
+            CPUID_EXT3_TOPOEXT,
         .features[FEAT_7_0_EBX] =
             CPUID_7_0_EBX_FSGSBASE | CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_AVX2 |
             CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_RDSEED |
@@ -1970,7 +1971,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_XSAVE_XGETBV1,
         .features[FEAT_6_EAX] =
             CPUID_6_EAX_ARAT,
-        .xlevel = 0x8000000A,
+        .xlevel = 0x8000001E,
         .model_id = "AMD EPYC Processor",
     },
     {
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 5/5] target/i386: Remove generic SMT thread check

[Babu Moger]

Remove generic non-intel check while validating hyperthreading support.
Certain AMD CPUs can support hyperthreading now.

CPU family with TOPOEXT feature can support hyperthreading now.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
 target/i386/cpu.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 6d06637..295c409 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4336,17 +4336,20 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 
     qemu_init_vcpu(cs);
 
-    /* Only Intel CPUs support hyperthreading. Even though QEMU fixes this
-     * issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
-     * based on inputs (sockets,cores,threads), it is still better to gives
+    /* Most Intel and certain AMD CPUs support hyperthreading. Even though QEMU
+     * fixes this issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
+     * based on inputs (sockets,cores,threads), it is still better to give
      * users a warning.
      *
      * NOTE: the following code has to follow qemu_init_vcpu(). Otherwise
      * cs->nr_threads hasn't be populated yet and the checking is incorrect.
      */
-    if (!IS_INTEL_CPU(env) && cs->nr_threads > 1 && !ht_warned) {
-        error_report("AMD CPU doesn't support hyperthreading. Please configure"
-                     " -smp options properly.");
+     if (IS_AMD_CPU(env) &&
+         !(env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) &&
+         cs->nr_threads > 1 && !ht_warned) {
+            error_report("This family of AMD CPU doesn't support "
+                         "hyperthreading. Please configure -smp "
+                         "options properly.");
         ht_warned = true;
     }
 
-- 
1.8.3.1