From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753624AbbFRI5G (ORCPT ); Thu, 18 Jun 2015 04:57:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52440 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752672AbbFRI45 (ORCPT ); Thu, 18 Jun 2015 04:56:57 -0400 Date: Thu, 18 Jun 2015 10:56:54 +0200 From: "Michael S. Tsirkin" To: Gerd Hoffmann Cc: "open list:VIRTIO CORE, NET..." , open list Subject: Re: [PATCH] virtio-pci: alloc only resources actually used. Message-ID: <20150618105628-mutt-send-email-mst@redhat.com> References: <1434463073-29648-1-git-send-email-kraxel@redhat.com> <20150616160052-mutt-send-email-mst@redhat.com> <1434615280.4968.14.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1434615280.4968.14.camel@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 18, 2015 at 10:14:40AM +0200, Gerd Hoffmann wrote: > Hi, > > > > +static struct resource *request_capability(struct pci_dev *dev, int off, > > > + const char *name) > > > +{ > > > + u8 bar; > > > + u32 offset, length; > > > + > > > + pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap, > > > + bar), > > > + &bar); > > > + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset), > > > + &offset); > > > + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > > + &length); > > > + > > > + return request_mem_region(pci_resource_start(dev, bar) + offset, > > > + length, name); > > > +} > > > + > > > > For device config, this might request too much. The spec says: > > The drivers SHOULD only map part of configuration structure large enough > > for device operation. > > We don't map it here though. We just reserve what belongs to virtio > according to the capabilities. > > > I think you should limit this to PAGE_SIZE like we do for map_capability. > > notify is much larger than PAGE_SIZE. Yes - I mean for the device config. > > > err = -EINVAL; > > > vp_dev->common = map_capability(pci_dev, common, > > > sizeof(struct virtio_pci_common_cfg), 4, > > > > map_capability has a bunch of checks in place to validate the capability > > structure. With request_capability called earlier, they are now done too > > late. > > Hmm, lets move the checks to find_capability then? > > cheers, > Gerd >