** Description changed: [Impact] QEMU crashes when passing through 8 GPU devices on an AMD Rome-based system which is configured (via BIOS) as a single NUMA domain. [Test Case] + + uvt-kvm create test + uvt-kvm wait test + uvt-kvm ssh test sudo poweroff + + virsh edit test + + # change: + # <driver name='qemu' type='qcow2'/> + # to: + # <driver name='qemu' type='qcow2' queues='128'/> + + virsh start test + virsh console test + + # QEMU will crash before booting into the kernel [Fix] the index into the bitmap array of batch_notify_vqs incremented itself by BITS_PER_LONG but then incorrectly indexed the unsigned long bitmap array by the full index value; when the number of vqs was under BITS_PER_LONG, the index was always 0, but once the number of vqs increased over BITS_PER_LONG, the bitmap array was indexed with (e.g. using BITS_PER_LONG == 64) bitmap[64] instead of bitmap[1]. Fix it to use the proper index by dividing the index counter by BITS_PER_LONG to get the bitmap array index. [Regression Risk] as this changes/fixes the index into an array, regressions would likely occur around notifications to the guest about virtio-blk device updates, or out-of-bounds errors in qemu itself, causing crash. [Scope] This is needed in b/e/f. This bug was introduced by commit e21737ab150c2742dd94089017db96c472dd4b87 which was introduced in version 2.7.0, so this bug does not exist in Xenial or earlier. This is fixed by commit 725fe5d10dbd4259b1853b7d253cef83a3c0d22a which is not yet in focal, but per comment 3 is included in the pending MR for focal. [other info] I added 'block-proposed' tags for b/e for this, to prevent release until after the patch has been released in focal.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1859527 Title: vring_get_region_caches: Assertion `caches != NULL' failed. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1859527/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
