Re: [PATCH v5 00/46] x86: Improve operation under QEMU

[Tom Rini <trini@konsulko.com>]

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On Sat, Mar 15, 2025 at 02:25:20PM +0000, Simon Glass wrote:

> U-Boot can start and boot an OS in both qemu-x86 and qemu-x86_64 but it
> is not perfect.
> 
> With both builds, executing the VESA ROM causes an intermittent hang, at
> least on some AMD CPUs.
> 
> With qemu-x86_64 kvm cannot be used since the move to long mode (64-bit)
> is done in a way that works on real hardware but not with QEMU. This
> means that performance is 4-5x slower than it could be, at least on my
> CPU.
> 
> We can work around the first problem by using Bochs, which is anyway a
> better choice than VESA for QEMU. The second can be addressed by using
> the same descriptor across the jump to long mode.
> 
> With an MTRR fix this allows booting into Ubuntu on qemu-x86_64
> 
> In v3 some e820 patches are included to make booting reliable and avoid
> ACPI tables being dropped. Also, several MTTR problems are addressed, to
> support memory sizes above 4GB reliably.

For the series, applied to u-boot/next, thanks.

-- 
Tom

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