FLOSS virtualization hacker, occasional brewer

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Joined 2 years ago
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Cake day: June 9th, 2023

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  • I work for a company that makes money supporting FLOSS. Our members pay fairly hefty membership fees because they have a vested interest in their chips being well supported by Linux and the wider ecosystem. That money funds common projects they all benefit from all well as numerous maintainers in projects keeping those projects ticking.

    The engineers on the project I mostly work on are predominantly paid to work on it. We value our hobbyist itch scratchers (~10% off contributors) but it’s commercial money that keeps those patches reviewed and flowing.






  • QEMU is always going to focus on emulation fidelity first and there are few shortcuts. With floating point the differences aren’t generally in the numbers but in how the NaNs and other edge cases are handled. If you want to execute FP heavy code you should be cross compiling anyway.





  • Pretty much. From v8.0 onwards all the extra features are indicated by id flags. Stuff that is relevant to kernel mode will generally be automatically handled by the kernel patching itself on booting up and in user space some libraries will select appropriately accelerated functions when the ISA extensions are probed. There are a bunch off advisory instructions encoded in the hint space that will be effectively NOPs on older hardware but will enhance execution if run on newer hardware.

    If you want to play with newer instructions have a look at QEMUs “max” CPU.