Re: [PATCH v4 09/10] x86/resctrl: Add arch_has_{sparse,empty}_bitmaps to explain CAT differences

Hi James, On 5/26/2020 6:40 AM, James Morse wrote: > Intel CPUs expect the cache bitmap provided by user-space to have on > a single span of 1s, whereas AMD can support bitmaps like 0xf00f. > Arm's MPAM support also allows sparse bitmaps. > > Similarly, Intel CPUs check at least one bit set,

[PATCH v4 09/10] x86/resctrl: Add arch_has_{sparse,empty}_bitmaps to explain CAT differences

Intel CPUs expect the cache bitmap provided by user-space to have on a single span of 1s, whereas AMD can support bitmaps like 0xf00f. Arm's MPAM support also allows sparse bitmaps. Similarly, Intel CPUs check at least one bit set, whereas AMD CPUs are quite happy with an empty bitmap. Arm's MPAM