Hi Dexuan, On Tue, 4 Apr 2023 20:11:18 +0000 Dexuan Cui <decui@xxxxxxxxxxxxx> wrote: > > From: Dexuan-Linux Cui <dexuan.linux@xxxxxxxxx> > > Sent: Tuesday, April 4, 2023 12:55 PM > > > > On Tue, Mar 21, 2023 at 1:37 AM Petr Tesarik > > <petrtesarik@xxxxxxxxxxxxxxx> wrote: > > ... > > > > Hi Petr, this patch has gone into the mainline: > > 0eee5ae10256 ("swiotlb: fix slot alignment checks") > > > > Somehow it breaks Linux VMs on Hyper-V: a regular VM with > > swiotlb=force or a confidential VM (which uses swiotlb) fails to boot. > > If I revert this patch, everything works fine. > > The log is pasted below. Looks like the SCSI driver hv_storvsc fails to > detect the disk capacity: The first thing I can imagine is that there are in fact no (free) slots in the SWIOTLB which match the alignment constraints, so the map operation fails. However, this would result in a "swiotlb buffer is full" message in the log, and I can see no such message in the log excerpt you have posted. Please, can you check if there are any "swiotlb" messages preceding the first error message? Petr T