* Andrew Jones (drjo...@redhat.com) wrote: > On Thu, Jan 12, 2017 at 10:42:41AM +0000, Peter Maydell wrote: > > On 12 January 2017 at 10:35, David Engraf <david.eng...@sysgo.com> wrote: > > > The CFI entry for sector length must be set to sector length per device. > > > This is important for boards using multiple devices like the ARM Vexpress > > > board (width = 4, device-width = 2). > > > > > > Linux and u-boots calculate the size ratio by dividing both values: > > > > > > size_ratio = info->portwidth / info->chipwidth; > > > > > > After that the sector length will be multiplied by the size_ratio, thus > > > the > > > CFI entry for sector length is doubled. When Linux or u-boot send a sector > > > erase, they expect to erase the doubled sector length, but QEMU only > > > erases > > > the board specified sector length. > > > > > > This patch fixes the sector length in the CFI table to match the length > > > per > > > device, equal to blocks_per_device. > > > > 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.
Hmm I don't understand enough about pflash to understand the change here; but generally if you need to keep something unchanged for older machine types, add a property and then set that property in the compatibility macros. See include/hw/compat.h, I think you'd add the entry to HW_COMPAT_2_8 and follow a simple example like old_msi_addr on intel-hda.c, that should get picked up by aarch, x86, ppc etc versioned machine types. Dave > Thanks, > drew -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
