[Xen-devel] [PATCH][HVM] Inject #GP for un-emulated instructions rather than crash guest

["Cui, Dexuan" <dexuan.cui@xxxxxxxxx>]

The CrashMe stress test (a process repeatedly forks child processes, and
the child processes initialize a buffer with random numbers, then treat
the buffer as code, and execute it) can crash 32-bit HVM RHEL5.1 guest
easily; this is because we haven't emulated all the instructions in
handle_mmio() yet.

The CrashMe process runs with root rights, and can access MMIO space in
an unknown way ("strace -f" shows the random codes running at CPL=3
don't call mmap(), and don't open any special files in /dev/ "); the gpa
may look like 0xa**** or  0xb****, or 0xfee0****.  
After running CrashMe for several hours, I have found 24 un-emulated
instructions may be hit...

This patch may serve as a workaround.

Signed-off-by: Dexuan Cui <dexuan.cui@xxxxxxxxx>

Attachment: inject_#GP_for_unemulated_instruction.patch
Description: inject_#GP_for_unemulated_instruction.patch

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