Re: [PATCH v4 02/23] x86/cpu: report SMX, TXT and SKINIT capabilities

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 20/08/2026 1:59 pm, Teddy Astie wrote:
> Le 02/08/2026 à 15:14, Sergii Dmytruk a écrit :
>> From: Michał Żygowski <michal.zygowski@xxxxxxxxx>
>>
>> Report TXT capabilities so that dom0 can query the Intel TXT or AMD
>> SKINIT support information using xl dmesg.
>>
>> Signed-off-by: Michał Żygowski <michal.zygowski@xxxxxxxxx>
>> Signed-off-by: Sergii Dmytruk <sergii.dmytruk@xxxxxxxxx>
>> ---
>>
>> Notes:
>>      v4: fixed conditions for not reporting capabilities (match
>> correct comments)
>>      v4: define GETSEC_* macros used only by xen/arch/x86/cpu/intel.c
>> in the file itself (to not depend on Slaunch)
>>      v4: don't postpone restoring state of X86_CR4_SMXE, do it before
>> printing test results
>>
>>   xen/arch/x86/cpu/amd.c   | 16 +++++++++++++
>>   xen/arch/x86/cpu/cpu.h   |  1 +
>>   xen/arch/x86/cpu/hygon.c |  1 +
>>   xen/arch/x86/cpu/intel.c | 50 ++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 68 insertions(+)
>>
>> diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c
>> index 70783c9a0a..5ea16ad8a8 100644
>> --- a/xen/arch/x86/cpu/amd.c
>> +++ b/xen/arch/x86/cpu/amd.c
>> @@ -617,6 +617,21 @@ void amd_process_freq(const struct cpuinfo_x86 *c,
>>           *low_mhz = amd_parse_freq(c->family, lo);
>>   }
>>   +void amd_log_skinit(const struct cpuinfo_x86 *c)
>> +{
>> +    /*
>> +     * Run only on BSP and not during resume to report the
>> capability only once.
>> +     */
>> +    if ( system_state == SYS_STATE_resume || smp_processor_id() )
>> +        return;
>> +
>> +    printk("CPU: SKINIT capability ");
>> +    if ( !test_bit(X86_FEATURE_SKINIT, &boot_cpu_data.x86_capability) )
>> +        printk("not supported\n");
>> +    else
>> +        printk("supported\n");
>> +}
>> +
>>   void cf_check early_init_amd(struct cpuinfo_x86 *c)
>>   {
>>       if (c == &boot_cpu_data)
>> @@ -1325,6 +1340,7 @@ static void cf_check init_amd(struct
>> cpuinfo_x86 *c)
>>           setup_force_cpu_cap(X86_FEATURE_XEN_REP_MOVSB);
>>         amd_log_freq(c);
>> +    amd_log_skinit(c);
>>   }
>
> On which Xen branch this patch is based ?
>
> early_init_amd() doesn't seem to have amd_log_freq (which is in
> init_amd instead).

See the cover letter:

base-commit: 7c77acd452fb6a3079661e75ebb5cf23ed985cc7

$ git describe 7c77acd452fb6a3079661e75ebb5cf23ed985cc7
4.23-dev-119-g7c77acd452fb

so it's something recent.