From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hollis Blanchard Date: Thu, 06 Nov 2008 04:54:04 +0000 Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants Message-Id: <200811052254.04409.hollisb@us.ibm.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ia64@vger.kernel.org On Wednesday 05 November 2008 22:49:42 Hollis Blanchard wrote: > virtio: Define and use per-architecture "pfn shift" constants > > Both sides of the virtio interface must agree about how big a pfn really is. > This is particularly an issue on architectures where the page size is > configurable (e.g. PowerPC, IA64) -- the interface must be independent of > PAGE_SHIFT. I forgot to mention that with this patch and the corresponding qemu patch, I can successfully use virtio with qemu TARGET_PAGE_BITS and Linux PAGE_SHIFT. (OK, actually I have other problems once I get to userspace, but I don't believe it's a virtio issue.) -- Hollis Blanchard IBM Linux Technology Center From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hollis Blanchard Date: Thu, 06 Nov 2008 04:54:04 +0000 Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants Message-Id: <200811052254.04409.hollisb@us.ibm.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: rusty@rustcorp.com.au Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-ia64@vger.kernel.org On Wednesday 05 November 2008 22:49:42 Hollis Blanchard wrote: > virtio: Define and use per-architecture "pfn shift" constants > > Both sides of the virtio interface must agree about how big a pfn really is. > This is particularly an issue on architectures where the page size is > configurable (e.g. PowerPC, IA64) -- the interface must be independent of > PAGE_SHIFT. I forgot to mention that with this patch and the corresponding qemu patch, I can successfully use virtio with qemu TARGET_PAGE_BITS and Linux PAGE_SHIFT. (OK, actually I have other problems once I get to userspace, but I don't believe it's a virtio issue.) -- Hollis Blanchard IBM Linux Technology Center From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hollis Blanchard Subject: Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants Date: Wed, 5 Nov 2008 22:54:04 -0600 Message-ID: <200811052254.04409.hollisb@us.ibm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-ia64@vger.kernel.org To: rusty@rustcorp.com.au Return-path: Received: from e36.co.us.ibm.com ([32.97.110.154]:54629 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752356AbYKFEyG (ORCPT ); Wed, 5 Nov 2008 23:54:06 -0500 In-Reply-To: Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: On Wednesday 05 November 2008 22:49:42 Hollis Blanchard wrote: > virtio: Define and use per-architecture "pfn shift" constants > > Both sides of the virtio interface must agree about how big a pfn really is. > This is particularly an issue on architectures where the page size is > configurable (e.g. PowerPC, IA64) -- the interface must be independent of > PAGE_SHIFT. I forgot to mention that with this patch and the corresponding qemu patch, I can successfully use virtio with qemu TARGET_PAGE_BITS=12 and Linux PAGE_SHIFT=16. (OK, actually I have other problems once I get to userspace, but I don't believe it's a virtio issue.) -- Hollis Blanchard IBM Linux Technology Center