CVS log for src/sys/dev/nvmm/x86/nvmm_x86_svm.c

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Current tag: thorpej-futex

Revision 1.82.2.1 / (download) - annotate - [select for diffs], Sat Apr 3 22:28:45 2021 UTC (3 years ago) by thorpej
Branch: thorpej-futex
Changes since 1.82: +3 -3 lines
Diff to previous 1.82 (colored) next main 1.83 (colored)

Sync with HEAD.

Revision 1.82 / (download) - annotate - [select for diffs], Sat Oct 24 07:14:30 2020 UTC (3 years, 5 months ago) by mgorny
Branch: MAIN
Branch point for: thorpej-futex, thorpej-cfargs
Changes since 1.81: +6 -4 lines
Diff to previous 1.81 (colored)

Issue 64-bit versions of *XSAVE* for 64-bit amd64 programs

When calling FXSAVE, XSAVE, FXRSTOR, ... for 64-bit programs on amd64
use the 64-suffixed variant in order to include the complete FIP/FDP
registers in the x87 area.

The difference between the two variants is that the FXSAVE64 (new)
variant represents FIP/FDP as 64-bit fields (union fp_addr.fa_64),
while the legacy FXSAVE variant uses split fields: 32-bit offset,
16-bit segment and 16-bit reserved field (union fp_addr.fa_32).
The latter implies that the actual addresses are truncated to 32 bits
which is insufficient in modern programs.

The change is applied only to 64-bit programs on amd64.  Plain i386
and compat32 continue using plain FXSAVE.  Similarly, NVMM is not
changed as I am not familiar with that code.

This is a potentially breaking change.  However, I don't think it likely
to actually break anything because the data provided by the old variant
were not meaningful (because of the truncated pointer).

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