On 06/13/2013 11:53 AM, Yinghai Lu wrote: > > - if (base & size_or_mask || size & size_or_mask) { > + if (base >> (boot_cpu_data.x86_phys_bits - PAGE_SHIFT) || > + base > (base + size) || > + (base + size - 1) >> (boot_cpu_data.x86_phys_bits - PAGE_SHIFT)) { > pr_warning("mtrr: base or size exceeds the MTRR width\n"); > return -EINVAL; > }
Most of this patch looks good as far as being a minimal patch, but I'm really confused about this bit. Could you explain the reason for why the original doesn't work? (To be fair: I am not even sure the original does anything useful so it could just be a "this is just too broken to live" kind of thing.) The first and third clause of the test can be simplified, however: (base | (base + size - 1)) >> (boot_cpu_data.x86_phys_bits - PAGE_SHIFT) ... although it would be cleaner to put boot_cpu_data.x86_phys_bits - PAGE_SHIFT into a variable. A lot of the mask_hi/mask_lo stuff should just get removed by using rdmsrl/wrmsrl, but that is not stable material obviously. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/