Re: [Xen-devel] [PATCH 1/2] guest/pvh: fix handling of multiboot info and module list

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Nov 12, 2018 at 08:12:56AM -0700, Jan Beulich wrote:
> >>> On 12.11.18 at 16:00, <roger.pau@xxxxxxxxxx> wrote:
> > Yes, it's only the module list that's passed by physical address and
> > then mapped using __va. How about the following description:
> > 
> > "When booting Xen as a PVH guest the data in the PVH start info
> > structure is copied over to a multiboot structure and a module list
> > array that resides in the .init section of the Xen image. The
> > resulting multiboot module list is then handed to the generic boot
> > process using the physical address in mbi->mods_addr.
> > 
> > This works fine as long as the Xen image doesn't relocate itself, if
> > there's such a relocation the physical addresses of multiboot module
> > list is no longer valid.
> > 
> > Fix this by handing the virtual address of the module list to the
> > generic boot process instead of it's physical address."
> 
> Sounds fine. But didn't Sergey spot two regions that were not
> taken care of? Or is the other part dealt with in patch 2?

IIRC the other one was the module(s) command line, which are relocated
in the low 1MB by pvh_info_reloc which should be fixed by patch #2.

Thanks, Roger.

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