On Thu, Nov 10, Boris Ostrovsky wrote:

> Are you sure it's this patch that causes the failure?
> 
> I commented out '| VM_IO' and still unable to boot with this option.

Yes, this works for me, sles12sp2 dom0+domU, which is linux-4.4 based:

+++ b/drivers/xen/gntdev.c
@@ -804,7 +804,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 
        vma->vm_ops = &gntdev_vmops;
 
-       vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+       vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP /*| VM_IO*/;
 
        if (use_ptemod)
                vma->vm_flags |= VM_DONTCOPY;

with this domU.cfg:

name="x"
memory=1024
serial="pty"
builder="hvm"
disk=[ 'vdev=xvda, direct-io-safe, backendtype=qdisk, target=x.raw', ]
vif=[ 'bridge=br0' ]
keymap="de"
cmdline="linemode=1 console=ttyS0,115200 ignore_loglevel install=http://host/sles_dvd1/ start_shell"
kernel= "/sles_dvd1/boot/x86_64/vmlinuz-xen"
ramdisk="/sles_dvd1/boot/x86_64/initrd-xen"


Without VM_IO 'fdisk -l /dev/xvda' works, with VM_IO 'fdisk -l
/dev/xvda' gives IO errors.

Olaf