On 08/29/2013 11:49 PM, Steve Reinhardt wrote:
What is the status of using kvm for x86 simulation?  I know Andreas S. has
committed a bunch of patches, but I see that x86 is still not listed
in the is_isa_kvm_compatible()
function in the SConstruct.  Does that mean there are still known issues?

Currently, the main issue that has kept me from submitting the patches is the x87 interface. gem5 uses 64-bit doubles internally to represent floating point numbers, while the hardware uses 80-bits. The problem boils down to converting between the two. My current version is using a gcc-specific 80-bit float type, which is something I need to fix before submitting. I have the code[1] to do the conversion in software, but I haven't had time to integrate it into gem5 yet.

Apart from the FP issues, things should work fine. I've seen less than 10% slowdown compared to native when executing SPEC and features like CPU switching and checkpointing work.

Unfortunately, I don't expect to get time to prepare the code for review until mid/late September.

//Andreas

[1] https://github.com/andysan/libfputils

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