On 2024-04-04 11:35:43, Alexey Kardashevskiy wrote: > First, sorry I am late into the discussion. Comments below. > > > On Thu, 28 Mar 2024, at 17:00, Kautuk Consul wrote: > > While testing with a qcow2 with a DOS boot partition it was found that > > when we set the logical_block_size in the guest XML to >512 then the > > boot would fail in the following interminable loop: > > Why would anyone tweak this? And when you do, what happens inside the SLOF, does it keep using 512? Well, we had an image with DOS boot partition and we tested it with logical_block_size = 1024 and got this infinite loop. In SLOF the block-size becomes what we configure in the logical_block_size parameter. This same issue doesn't arise with GPT. > > > <SNIP> > > Trying to load: from: /pci@800000020000000/scsi@3 ... > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > </SNIP> > > > > Change the "read-sector" Forth subroutine to throw an exception whenever > > it fails to read a full block-size length of sector from the disk. > > Why not throwing an exception from the "beyond end" message point? > Or fail to open a device if SLOF does not like the block size? I forgot the internals :( This loop is interminable and this "Access beyond end of device!" message continues forever. SLOF doesn't have any option other than to use the block-size that was set in the logical_block_size parameter. It doesn't have any preference as the code is very generic for both DOS as well as GPT. > > > Also change the "open" method to initiate CATCH exception handling for the calls to > > try-partitions/try-files which will also call read-sector which could potentially > > now throw this new exception. > > > > After making the above changes, it fails properly with the correct error > > message as follows: > > <SNIP> > > Trying to load: from: /pci@800000020000000/scsi@3 ... > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > virtioblk_transfer: Access beyond end of device! > > > > E3404: Not a bootable device! > > > > E3407: Load failed > > > > Type 'boot' and press return to continue booting the system. > > Type 'reset-all' and press return to reboot the system. > > > > Ready! > > 0 > > > </SNIP> > > > > Signed-off-by: Kautuk Consul <kconsul@xxxxxxxxxxxxx> > > --- > > slof/fs/packages/disk-label.fs | 12 +++++++++--- > > 1 file changed, 9 insertions(+), 3 deletions(-) > > > > diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs > > index 661c6b0..a6fb231 100644 > > --- a/slof/fs/packages/disk-label.fs > > +++ b/slof/fs/packages/disk-label.fs > > @@ -136,7 +136,8 @@ CONSTANT /gpt-part-entry > > : read-sector ( sector-number -- ) > > \ block-size is 0x200 on disks, 0x800 on cdrom drives > > block-size * 0 seek drop \ seek to sector > > - block block-size read drop \ read sector > > + block block-size read \ read sector > > + block-size < IF throw THEN \ if we read less than the block-size then throw an exception > > When it fails, is the number of bytes ever non zero? Thanks, No, it doesn't reach 0. It is lesser than the block-size. For example if we set the logcial_block_size to 1024, the block-size is that much. if we are reading the last sector which is physically only 512 bytes long then we read that 512 bytes which is lesser than 1024, which should be regarded as an error. > > > ; > > > > : (.part-entry) ( part-entry ) > > @@ -723,10 +724,15 @@ CREATE GPT-LINUX-PARTITION 10 allot > > THEN > > > > partition IF > > - try-partitions > > + ['] try-partitions > > ELSE > > - try-files > > + ['] try-files > > THEN > > + > > + \ Catch any exception that might happen due to read-sector failing to read > > + \ block-size number of bytes from any sector of the disk. > > + CATCH IF false THEN Segher/Alexey, can we keep this CATCH block or should I remove it ? > > + > > dup 0= IF debug-disk-label? IF ." not found." cr THEN close THEN \ free memory again > > ; > > > > -- > > 2.31.1 > > > >
