On Wed, 20 May 2020 19:10:07 +0530 Kirti Wankhede <kwankhede@xxxxxxxxxx> wrote: > On 5/20/2020 8:25 AM, Yan Zhao wrote: > > On Tue, May 19, 2020 at 10:58:04AM -0600, Alex Williamson wrote: > >> Hi folks, > >> > >> My impression is that we're getting pretty close to a workable > >> implementation here with v22 plus respins of patches 5, 6, and 8. We > >> also have a matching QEMU series and a proposal for a new i40e > >> consumer, as well as I assume GVT-g updates happening internally at > >> Intel. I expect all of the latter needs further review and discussion, > >> but we should be at the point where we can validate these proposed > >> kernel interfaces. Therefore I'd like to make a call for reviews so > >> that we can get this wrapped up for the v5.8 merge window. I know > >> Connie has some outstanding documentation comments and I'd like to make > >> sure everyone has an opportunity to check that their comments have been > >> addressed and we don't discover any new blocking issues. Please send > >> your Acked-by/Reviewed-by/Tested-by tags if you're satisfied with this > >> interface and implementation. Thanks! > >> > > hi Alex and Kirti, > > after porting to qemu v22 and kernel v22, it is found out that > > it can not even pass basic live migration test with error like > > > > "Failed to get dirty bitmap for iova: 0xca000 size: 0x3000 err: 22" > > > > Thanks for testing Yan. > I think last moment change in below cause this failure > > https://lore.kernel.org/kvm/1589871178-8282-1-git-send-email-kwankhede@xxxxxxxxxx/ > > > if (dma->iova > iova + size) > > break; > > Surprisingly with my basic testing with 2G sys mem QEMU didn't raise > abort on g_free, but I do hit this with large sys mem. > With above change, that function iterated through next vfio_dma as well. > Check should be as below: > > - if (dma->iova > iova + size) > + if (dma->iova > iova + size -1) Or just: if (dma->iova >= iova + size) Thanks, Alex > break; > > Another fix is in QEMU. > https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg04751.html > > > > + range->bitmap.size = ROUND_UP(pages, 64) / 8; > > > > ROUND_UP(npages/8, sizeof(u64))? > > > > If npages < 8, npages/8 is 0 and ROUND_UP(0, 8) returns 0. > > Changing it as below > > - range->bitmap.size = ROUND_UP(pages / 8, sizeof(uint64_t)); > + range->bitmap.size = ROUND_UP(pages, sizeof(__u64) * > BITS_PER_BYTE) / > + BITS_PER_BYTE; > > I'm updating patches with these fixes and Cornelia's suggestion soon. > > Due to short of time I may not be able to address all the concerns > raised on previous versions of QEMU, I'm trying make QEMU side code > available for testing for others with latest kernel changes. Don't > worry, I will revisit comments on QEMU patches. Right now first priority > is to test kernel UAPI and prepare kernel patches for 5.8 > > Thanks, > Kirti >
