On Tue, Feb 21 2023 at 19:05, Chang S. Bae wrote:
On 2/21/2023 8:36 AM, Mingwei Zhang wrote:
@@ -1151,10 +1152,11 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate, pkru.pkru = pkru_val; membuf_write(&to, &pkru, sizeof(pkru)); } else {
copy_feature(header.xfeatures & BIT_ULL(i), &to,__raw_xsave_addr(xsave, i),__raw_xsave_addr(xinit, i),xstate_sizes[i]);
xsave_addr = (header.xfeatures & BIT_ULL(i)) ?__raw_xsave_addr(xsave, i) :__raw_xsave_addr(xinit, i);membuf_write(&to, xsave_addr, xstate_sizes[i]);
- Keep track of the last copied state in the non-compacted
So this hunk is under for_each_extended_xfeature(i, mask) -- it skips the copy routine if mask[i] == 0; instead, it fills zeros.
We have this [1]:
if (fpu_state_size_dynamic()) mask &= (header.xfeatures | xinit->header.xcomp_bv);
If header.xfeatures[18] = 0 then mask[18] = 0 because xinit->header.xcomp_bv[18] = 0. Then, it won't hit that code. So, I'm confused about the problem that you described here.
Read the suggested changelog I wrote in my reply to Mingwei.
TLDR:
xsave.header.xfeatures[18] = 1 xinit.header.xfeatures[18] = 0 -> mask[18] = 1 -> __raw_xsave_addr(xsave, 18) <- Success -> __raw_xsave_addr(xinit, 18) <- WARN
Thanks,
tglx