Re: [PATCH V2] hw/riscv: virt: Remove size restriction for pflash

[Peter Maydell]

On Mon, 7 Nov 2022 at 14:08, Sunil V L <sunilvl@ventanamicro.com> wrote:
>
> On Mon, Nov 07, 2022 at 01:06:38PM +0000, Peter Maydell wrote:
> > On Mon, 7 Nov 2022 at 13:03, Sunil V L <sunilvl@ventanamicro.com> wrote:
> > >
> > > The pflash implementation currently assumes fixed size of the
> > > backend storage. Due to this, the backend storage file needs to be
> > > exactly of size 32M. Otherwise, there will be an error like below.
> > >
> > > "device requires 33554432 bytes, block backend provides 4194304 bytes"
> > >
> > > Fix this issue by using the actual size of the backing store.
> > >
> > > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > > ---
> >
> > Do you really want the flash device size presented to the guest
> > to be variable depending on what the user passed as a block backend?
> > I don't think this is how we handle flash devices on other boards...
> >

> x86 appears to support variable flash but arm doesn't. What is
> the reason for not supporting variable size flash in arm?

Mostly, that that's the straightforward thing to code.
Partly, that it avoids weird cases (eg you can have a backing
file that's an odd number of bytes but you can't have a
flash that size).

If x86 has a standard way of handling this then I'm all
in favour of being consistent across platforms. What's
the x86 board doing there?

thanks
-- PMM