Re: [PATCH v3 4/8] target/i386/intel-pt: print special message for INTEL_PT_ADDR_RANGES_NUM

[Chenyi Qiang]

On 12/13/2022 8:09 PM, Xiaoyao Li wrote:
> On 12/9/2022 2:43 PM, Chenyi Qiang wrote:
>>
>>
>> On 12/8/2022 2:25 PM, Xiaoyao Li wrote:
>>> Bit[2:0] of CPUID.14H_01H:EAX stands as a whole for the number of INTEL
>>> PT ADDR RANGES. For unsupported value that exceeds what KVM reports,
>>> report it as a whole in mark_unavailable_features() as well.
>>>
>>
>> Maybe this patch can be put before 3/8.
> 
> patch 3 introduces the logic to check bit 2:0 of CPUID leaf 14_1 as
> whole. So it's better to be after patch 3.
> 
> +            /* Bits 2:0 are as a whole to represent
> INTEL_PT_ADDR_RANGES */
> +            if ((requested_features & INTEL_PT_ADDR_RANGES_NUM_MASK) >
> +                (host_feat & INTEL_PT_ADDR_RANGES_NUM_MASK)) {
> +                unavailable_features |= requested_features &
> +                                        INTEL_PT_ADDR_RANGES_NUM_MASK;
> 

Yeah, I didn't notice Eduardo prefer having duplicate error message
showing bit 2,1,0 which I considered to avoid. Then it's OK.

>>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>>> ---
>>>   target/i386/cpu.c | 9 ++++++++-
>>>   1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>>> index 65c6f8ae771a..4d7beccc0af7 100644
>>> --- a/target/i386/cpu.c
>>> +++ b/target/i386/cpu.c
>>> @@ -4387,7 +4387,14 @@ static void mark_unavailable_features(X86CPU
>>> *cpu, FeatureWord w, uint64_t mask,
>>>           return;
>>>       }
>>>   -    for (i = 0; i < 64; ++i) {
>>> +    if ((w == FEAT_14_1_EAX) && (mask &
>>> INTEL_PT_ADDR_RANGES_NUM_MASK)) {
>>> +        warn_report("%s: CPUID.14H_01H:EAX [bit 2:0]", verbose_prefix);
>>> +        i = 3;
>>> +    } else {
>>> +        i = 0;
>>> +    }
>>> +
>>> +    for (; i < 64; ++i) {
>>>           if ((1ULL << i) & mask) {
>>>               g_autofree char *feat_word_str =
>>> feature_word_description(f, i);
>>>               warn_report("%s: %s%s%s [bit %d]",
>