[vbox-dev] [PATCH] Some 64-bit fixes
gbeauchesne at mandriva.com
Mon Feb 5 08:17:26 PST 2007
> Thanks for the patches. However it would help if you described briefly
> what problems the different changes attempt to fix and in some cases
> explain why they fix it...
OK, sorry, there were 4 parts:
- cpuid() stuff. I actually got a SIGSEGV when I built vbox in
BUILD_TYPE=release (default) mode. I have not really looked at the
generated code but rather reimplemented it the way I was used too. ;-)
I believe the constraint should have used "+r" to indicate an
input/output register for the "=r" (*(uint32_t *)pvEBX) part.
- For the QEMU part. I also got a SIGSEGV in either
REMR3EmulateInstruction() or REMR3Run(). By binary code pattern
matching, I determined that the offending code was actually cpu_exec()
where I could realise the callee-saved registers (here, %rbx) where not
saved completely (the upper-half 32-bit were trashed away).
- The xpidl_util.c change was motivated from code inspection after
looking at the build logs (warnings). strdup() was not defined, thus
defaulting to (int) return which can yield to pointer truncation.
Actually, I have not experienced the problem but it was my first
attempt to review all pending warnings when building on x86_64.
- The last part was obvious since the PIDs printed out in the VBox
error box looked the same so one of them was likely 64-bit with
upper-bits non-zero as a NIL_RTPROCESS would be. The correct fix would
have been to make RTPROCESS an integer type exactly as large as an
ULONG (which turns out to use the Win32 semantics, i.e. a 32-bit value).
Thank you for VirtualBox and its decently commented code. ;-)
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