[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH] x86/Intel: don't log bogus frequency range on Core/Core2 processors
Models 0F and 17 don't have PLATFORM_INFO documented. While it exists on at least model 0F, the information there doesn't match the scheme used on newer models (I'm observing a range of 700 ... 600 MHz reported on a Xeon E5345). Sadly the Enhanced Intel Core instance of the table entry is not self- consistent: The numeric description of the low 3 bits doesn't match the subsequent more textual description in some of the cases; I'm using the former here. Include the older Core model 0E as well as the two other Core2 models, none of which have respective MSR tables in the SDM. Fixes: f6b6517cd5db ("x86: retrieve and log CPU frequency information") Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> --- While the SDM table for the two models lists FSB_FREQ, I'm afraid its information is of little use here: If anything it could serve as a reference for the frequency determined by calibrate_APIC_clock(). --- RFC: I may want to rebase over Roger's addition of intel-family.h, but first of all I wanted to see whether going this route is deemed acceptable at all. --- a/xen/arch/x86/cpu/intel.c +++ b/xen/arch/x86/cpu/intel.c @@ -435,6 +435,26 @@ static void intel_log_freq(const struct if ( c->x86 == 6 ) switch ( c->x86_model ) { + static const unsigned short core_factors[] = + { 26667, 13333, 20000, 16667, 33333, 10000, 40000 }; + + case 0x0e: /* Core */ + case 0x0f: case 0x16: case 0x17: case 0x1d: /* Core2 */ + /* + * PLATFORM_INFO, while not documented for these, appears to + * exist in at least some cases, but what it holds doesn't + * match the scheme used by newer CPUs. At a guess, the min + * and max fields look to be reversed, while the scaling + * factor is encoded in FSB_FREQ. + */ + if ( min_ratio > max_ratio ) + SWAP(min_ratio, max_ratio); + if ( rdmsr_safe(MSR_FSB_FREQ, msrval) || + (msrval &= 7) >= ARRAY_SIZE(core_factors) ) + return; + factor = core_factors[msrval]; + break; + case 0x1a: case 0x1e: case 0x1f: case 0x2e: /* Nehalem */ case 0x25: case 0x2c: case 0x2f: /* Westmere */ factor = 13333;
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