Re: [PATCH v2 00/28] x86: Improve operation under QEMU

[Tom Rini <trini@konsulko.com>]

[-- Attachment #1: Type: text/plain, Size: 1606 bytes --]

On Mon, Feb 17, 2025 at 06:14:12AM -0700, Simon Glass wrote:
> Hi Tom,
> 
> On Sun, 16 Feb 2025 at 14:57, Tom Rini <trini@konsulko.com> wrote:
> >
> > On Sun, Feb 16, 2025 at 01:43:45PM -0700, 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
> >
> > This seems needlessly not against mainline.
> 
> I just tried it and yes there is a very small delta. I can resend it
> rebased to -next if you like. I'd really like to get some OS-booting
> tests into CI.

Sure, and please start pushing scripts to u-boot-extras. Having these
scripts in u-boot itself explicitly makes it harder to use them for
debug as you now rely on them being within the tree with the changes you
want on whatever older commit you want. And since you want to move these
to Python too you that also means language updates need to be in there
as well. Thanks.

-- 
Tom

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 659 bytes --]