From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hollis Blanchard Date: Tue, 04 Nov 2008 22:14:20 +0000 Subject: large page size virtio issues Message-Id: <1225836860.15410.32.camel@localhost.localdomain> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org Hi Rusty, I'm using a patch that changes the Linux base page size to 64K. (This is actually pretty common in ppc64 world, but I happen to be trying it on ppc32.) I'm seeing a problem with virtio. I think at least part of it can be explained by qemu's TARGET_PAGE_BITS=12, and the guest's PAGE_SHIFT=16. The guest allocates the queue, then passes the pfn (pa >> PAGE_SHIFT) to the virtio backend (vp_find_vq()). The backend then calculates the pa as pfn << TARGET_PAGE_BITS. I have to run right now, but quickly changing qemu TARGET_PAGE_BITS to 16 got me a little further but still didn't work. Any thoughts? Thanks! -- Hollis Blanchard IBM Linux Technology Center