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

[Dave Young]

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)

So I think these 3 patches are good,  but there could be other issues
which is not related to the problem we saw.

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

Thanks
Dave