Re: [PATCH v6 1/2] x86/kexec: Build identity mapping for EFI systab and ACPI tables

[Baoquan He]

On 05/14/19 at 11:22am, Dave Young wrote:
> On 05/13/19 at 04:06pm, Baoquan He wrote:
> > Hi Dave,
> > 
> > On 05/13/19 at 09:50am, Borislav Petkov wrote:
> > > On Mon, May 13, 2019 at 03:32:54PM +0800, Baoquan He wrote:
> > > > This is a critical bug which breaks memory hotplug,
> > > 
> > > Please concentrate and stop the blabla:
> > > 
> > > 36f0c423552d ("x86/boot: Disable RSDP parsing temporarily")
> > > 
> > > already explains what the deal is. This code was *purposefully* disabled
> > > because we ran out of time and it broke a couple of machines. Don't make
> > 
> > I remember your machine is the one on whihc the issue is reported. Could
> > you also test it and confirm if these all things found ealier are
> > cleared out?
> > 
> 
> I did some tests on the laptop,  thing is:
> 1. apply the 3 patches (two you posted + Boris's revert commit 52b922c3d49c)
>    on latest Linus master branch, everything works fine.
> 
> 2. build and test the tip/next-merge-window branch, kernel hangs early
> without output, (both 1st boot and kexec boot)

Thanks, Dave.

Yeah, I also tested on a HP machine, problem reprodued on the current
master branch when revert commit 52b922c3d49c.

Then apply these two patches, problem solved.

Tried boris's next-merge-window branch too, kexec works very well.

Dirk, Junichi, feel free to add your test result if you have time.

> 
> Another thing is we can move the get rsdp after console_init, but that
> can be done later as separate patch.

Yes, agree.