Re: [PATCH for-4.20 v2] x86/intel: Fix PERF_GLOBAL fixup when virtualised

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 21/01/2025 5:04 pm, Jan Beulich wrote:
> On 21.01.2025 17:56, Andrew Cooper wrote:
>> --- a/xen/arch/x86/cpu/intel.c
>> +++ b/xen/arch/x86/cpu/intel.c
>> @@ -535,39 +535,49 @@ static void intel_log_freq(const struct cpuinfo_x86 *c)
>>      printk("%u MHz\n", (factor * max_ratio + 50) / 100);
>>  }
>>  
>> +static void init_intel_perf(struct cpuinfo_x86 *c)
>> +{
>> +    uint64_t val;
>> +    unsigned int eax, ver, nr_cnt;
>> +
>> +    if ( c->cpuid_level <= 9 ||
>> +         ({  rdmsrl(MSR_IA32_MISC_ENABLE, val);
> Just curious (not an objection or anything): Is there a reason you have
> two padding blanks here instead of just one?

Alignment with the next line.

> (Really we may want to gain
> a function-like form to invoke RDMSR, but that's orthogonal to the change
> here.)

Indeed.

* def0701b5373 - (xen-nj-msr) switch rdmsrl => rdmsr (30 hours ago)
<Andrew Cooper>
* 1a3f92abccf1 - rdmsr (30 hours ago) <Andrew Cooper>
* 01c9ec7d9482 - rdmsr_safe (30 hours ago) <Andrew Cooper>
* 7ec72a0379b2 - fix error printing in write_msr() (30 hours ago)
<Andrew Cooper>
* 3ff3d60835a5 - drop wrmsrl (30 hours ago) <Andrew Cooper>
* 136128799b4a - wrmsr cleanup (30 hours ago) <Andrew Cooper>
* b2ed78d2e7e3 - x86/msr: Move MSR_FEATURE_CONTROL handling to the new
MSR infrastructure (30 hours ago) <Andrew Cooper>
* 7691edea3d67 - x86/msr: Clean up the MSR_DEBUGCTL constants (30 hours
ago) <Andrew Cooper>
* 77ba2827a955 - x86/msr: Clean up the MSR_MISC_ENABLE constants (30
hours ago) <Andrew Cooper>
* 7f2768cfc4b3 - ---upstream--- (30 hours ago) <Andrew Cooper>
* 8b2e048fdd14 - x86/msr: Introduce msr_{set,clear}_bits() helpers (30
hours ago) <Andrew Cooper>
* 562f88503342 - x86/msr: Clean up the MSR_FEATURE_CONTROL constants (30
hours ago) <Andrew Cooper>
* 199888c9e2f8 - x86/msr: Clean up the
MSR_{PLATFORM_INFO,MISC_FEATURES_ENABLES} constants (30 hours ago)
<Andrew Cooper>
* c3f5d1bb40b5 - (tag: 4.20.0-rc2, xenbits/staging, xenbits/master,
upstream/staging, upstream/master, origin/staging, origin/master,
origin/HEAD, staging, pending, master) automation/cirrus-ci: introduce
FreeBSD randconfig builds (4 days ago) <Roger Pau Monne>

That was work I did while sat in an airport unable to leave XenSummit in
Nanjing...

It's blocked on arguments over naming.

~Andrew