Re: [Qemu-block] [Qemu-devel] [PATCH] pflash_cfi01: fix per device sector length in CFI table

[Andrew Jones]

On Fri, Jan 27, 2017 at 02:54:20PM +0000, Peter Maydell wrote:
> On 27 January 2017 at 14:31, Peter Maydell <address@hidden> wrote:
> > On 12 January 2017 at 11:36, Andrew Jones <address@hidden> wrote:
> >> On Thu, Jan 12, 2017 at 10:42:41AM +0000, Peter Maydell wrote:
> >>> Thanks for the patch. I haven't checked against the pflash spec yet,
> >>> but this looks like it's probably the right thing.
> >>>
> >>> The only two machines which use a setup with multiple devices (ie
> >>> which specify device_width to the pflash_cfi01) are vexpress and virt.
> >>> For all other machines this patch leaves the behaviour unchanged.
> >>>
> >>> Q: do we need to have some kind of nasty hack so that pre-2.9 virt
> >>> still gets the old broken values in the CFI table, for version and
> >>> migration compatibility? Ccing Drew for an opinion...
> >>>
> >>
> >> I'm pretty sure we need the nasty hack, but I'm also Ccing David for
> >> his opinion.
> >
> > So given our decision about not needing the back-compat property
> > for the UEFI table entry, do we still agree that we need one here?
> 
> Looking more closely at the patch, changing writeblock underneath
> a guest's feet is probably not very polite, so let's take the safe
> path of making it version-dependent.

Right, and I think ACPI generation is getting a bit of special treatment
due to its status as "part of firmware". Hardware should probably never
change.

> 
> I've applied David's patch to target-arm.next (with some tweaks to
> the commit message).
> 
> thanks
> -- PMM

Thanks,
drew