On 10.02.20 10:50, Shameerali Kolothum Thodi wrote: > > >> -----Original Message----- >> From: David Hildenbrand [mailto:da...@redhat.com] >> Sent: 10 February 2020 09:29 >> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>; >> Igor Mammedov <imamm...@redhat.com> >> Cc: peter.mayd...@linaro.org; xiaoguangrong.e...@gmail.com; >> m...@redhat.com; shannon.zha...@gmail.com; qemu-devel@nongnu.org; >> xuwei (O) <xuw...@huawei.com>; Linuxarm <linux...@huawei.com>; >> eric.au...@redhat.com; qemu-...@nongnu.org; ler...@redhat.com >> Subject: Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback >> >>>> Can you look the original value up somehow and us the resize callback >>>> only as a notification that something changed? (that value would have to >>>> be stored somewhere and migrated I assume - maybe that's already being >>>> done) >>> >>> Ok. I will take a look at that. But can we instead pass the >>> block->used_length >> to >>> fw_cfg_add_file_callback(). That way we don’t have to change the >> qemu_ram_resize() >>> as well. I think Igor has suggested this before[1] and I had a go at it >>> before >> coming up >>> with the "req_length" proposal here. >> >> You mean, passing the old size as well? I don't see how that will solve >> the issue, but yeah, nothing speaks against simply sending the old and >> the new size. > > Nope. I actually meant using the block->used_length to store in the > s->files->f[index].size. > > virt_acpi_setup() > acpi_add_rom_blob() > rom_add_blob() > rom_set_mr() --> used_length = page aligned blob size > fw_cfg_add_file_callback() --> uses actual blob size. > > > Right now what we do is use the actual blob size to store in FWCfgEntry. > Instead pass the RAMBlock used_length to fw_cfg_add_file_callback(). > Of course by this, the firmware will see an aligned size, but that is fine I > think. > But at the same time this means the qemu_ram_resize() can stay as it is > because it will invoke the callback when the size changes beyond the aligned > page size. And also during migration, there won't be any inconsistency as > everyone > works on aligned page size. > > Does that make sense? Or I am again missing something here?
Oh, you mean simply rounding up to full pages in the fw entries? If we can drop the "sub-page" restriction, that would be awesome! Need to double check if that could be an issue for fw/migration/whatever. -- Thanks, David / dhildenb
