On 11/27/13 14:52, Markus Armbruster wrote: > Jordan Justen <jljus...@gmail.com> writes: > >> On Tue, Nov 26, 2013 at 5:32 AM, Laszlo Ersek <ler...@redhat.com> wrote: >>> On 11/26/13 13:36, Markus Armbruster wrote: >>> >>>> Your stated purpose for multiple -pflash: >>>> >>>> This accommodates the following use case: suppose that OVMF is split in >>>> two parts, a writeable host file for non-volatile variable storage, >>>> and a >>>> read-only part for bootstrap and decompressible executable code. >>>> >>>> Such a split between writable part and read-only part makes sense to me. >>>> How is it done in physical hardware? Single device with configurable >>>> write-protect, or two separate devices? >>> >>> (Jordan could help more.) >>> >>> Likely one device that's fully writeable. >> >> Most parts will have a dedicated read-only line. >> >> Many devices have 'block-locking' that will make some subset of blocks >> read-only until a reset. >> >> In addition to this, many chipsets will allow flash writes to be >> protected by triggering SMM when a flash write occurs. >> >> Using multiple chips are less common due to cost, but this is not a >> factor for QEMU. :) > > Should we stick to what real hardware does? Single device, perhaps with > block locking.
I can't back a single flash device with two drives (= two host-side files), which is the incentive for this change. Thanks Laszlo
