Messages in this thread |  | | Date | Mon, 15 Aug 2005 23:08:04 -0400 | From | Brian Gerst <> | Subject | Re: [PATCH 0/6] i386 virtualization patches, Set 3 |
| |
zach@vmware.com wrote: > This round attempts to conclude all of the LDT related cleanup with some > finally nice looking LDT code, fixes for the UML build, a bugfix for > really rather nasty kprobes problems, and the basic framework for an LDT > test suite. It is really rather unfortunate that this code is so > difficult to test, even with DOSemu and Wine, there are still very nasty > corner cases here - anyone want an iret to 16-bit stack test?. > > I was going to attempt to clean up the math-emu code to make it use the > nice new segment and descriptor table accessors, but it quickly became > apparent that this would be a long, tedious, error prone process that > would eventually result in the death of a large section of my brain. > In addition, it is not very fun to test this on the actual hardware it > is designed to run on (although I did manage to track down a 386 with > detachable i387 coprocessor, the owner is not sure it still boots). > Someday it would be nice to have an audit of this code; it appears to > be riddled with bugs relating to segmentation, for example it assumes > LDT segments on overrides, does not use the mm->context semaphore to > protect LDT access, and generally looks scarily out of date in both > function and appearance.
If you really want to test the math emu code, you can hack check_x87 in head.S to always leave the fpu disabled. Then you can test it on any cpu, not just a 386.
-- Brian Gerst - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |