On Mar 24, 2021, at 22:12, Liu, Jing2 <jing2....@linux.intel.com> wrote: > On 3/25/2021 5:09 AM, Len Brown wrote: >> >> For AMX, we must still reserve the space, but we are not going to write zeros >> for clean state. We so this in software by checking XINUSE=0, and clearing >> the xstate_bf for the XSAVE. As a result, for XINUSE=0, we can skip >> writing the zeros, even though we can't compress the space. > So my understanding is that clearing xstate_bv will not help prevent saving > zeros, but only not masking EDX:EAX, since the following logic. Not sure if > this is just what you mean. :)
FWIW, PATCH21 [1] uses the instruction mask to skip writing zeros on sigframe. Then, XSAVE will clear the xstate_bv for the xtile data state bit. [1] https://lore.kernel.org/lkml/20210221185637.19281-22-chang.seok....@intel.com/ Thanks, Chang
