Le jeu. 5 mai 2022, 15:55, Stefan Agner <ste...@agner.ch> a écrit : > Despite the UEFI specification saying "the requirement is that the > start address of a buffer must be evenly divisible by IoAlign with > no remainder.", it seems that a higher alignment requirement is > neecssary on some system (e.g. a Intel NUC system with NVMe SSD). > That particular system has IoAlign set to 2, and sometimes returns > status 7 when buffers with alignment of 2 are passed. Things seem > to work fine with buffers aligned to 4 bytes. > > It seems that IoAlign > 1 means 2 ^ IoAlign. There is also such a hint > in an example printed in the Driver Writer's Guide: > ScsiPassThruMode.IoAlign = 2; // Data must be alligned on 4-byte boundary > > Pass 2 ^ IoAlign aligned buffers to make sure GRUB2 works properly on > all systems. > > Note: The problem has only noticed with compressed squashfs. It seems > that ext4 (and presumably other file system drivers) pass buffers with > a higher alignment already. > > Signed-off-by: Stefan Agner <ste...@agner.ch> > --- > grub-core/disk/efi/efidisk.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/grub-core/disk/efi/efidisk.c b/grub-core/disk/efi/efidisk.c > index f077b5f55..0fc2f0826 100644 > --- a/grub-core/disk/efi/efidisk.c > +++ b/grub-core/disk/efi/efidisk.c > @@ -553,8 +553,16 @@ grub_efidisk_readwrite (struct grub_disk *disk, > grub_disk_addr_t sector, > d = disk->data; > bio = d->block_io; > > - /* Set alignment to 1 if 0 specified */ > - io_align = bio->media->io_align ? bio->media->io_align : 1; > + /* > + * If IoAlign is > 1, it means alignment by 2^IoAlign > + * Note: UEFI spec claims alignment by IoAlign. But there are systems > + * with IoAlign=2 which return status 7 if 2 bytes aligned buffers are > + * passed. > + */ > + if (bio->media->io_align > 1) > + io_align = 1 << bio->media->io_align; > + else > + io_align = 1; > May be it should be >=1 rather than > 1?
> num_bytes = size << disk->log_sector_size; > > if ((grub_addr_t) buf & (io_align - 1)) > -- > 2.36.0 > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >
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