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Diffstat (limited to 'open_issues')
| -rw-r--r-- | open_issues/xen_crash_copy-size_le_page_size.mdwn | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/open_issues/xen_crash_copy-size_le_page_size.mdwn b/open_issues/xen_crash_copy-size_le_page_size.mdwn index 58784e96..0aa030fd 100644 --- a/open_issues/xen_crash_copy-size_le_page_size.mdwn +++ b/open_issues/xen_crash_copy-size_le_page_size.mdwn @@ -77,3 +77,28 @@ GDB on `mkfs.ext2`: #3 0x0805e87d in ext2fs_zero_blocks (fs=0x8082940, blk=524272, num=16, ret_blk=0x15ffb1c, ret_count=0x0) at ../../../git/lib/ext2fs/mkjournal.c:182 #4 0x0804ec56 in main (argc=131072, argv=0x80000) at ../../git/misc/mke2fs.c:2032 + +Discussion: + + <tschwinge> I had a look at the code, but unfortunately don't really know + how this data transfers between Xen and the domU work. + <tschwinge> Well, I know how it roughly works, but not the implementation + deatils. + <youpi> well here it's not about the xen/domU transfers + <youpi> it's about copying data to align it + <youpi> i.e. when offset is not aligned, I need to copy it + <tschwinge> Yes- + <youpi> I was lazy, just implemented it for things smaller than a page + <youpi> it just needs to be extended into copying several pages + <tschwinge> youpi: Hmm, do we need to copy all the data to shift away the + offset or is there a better way? + <youpi> the blkbackend needs data to be sector-aligned + <youpi> just aligning on a page makes offset computation simpler + <youpi> as it's rare that's not a problem + <tschwinge> And a sector is the usual 512 bytes there, I assume? + <tschwinge> But then we do need to copy all of it? + <youpi> let me check + <youpi> the sector is the granularity you can't go below + <youpi> sector is the sector_size reported by the backend + <youpi> but for sector_number and first/last_sect it's 512 + <youpi> yes, that's weird |