From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges Date: Wed, 15 Jul 2015 12:05:35 +0100 Message-ID: References: <1436420047-25356-1-git-send-email-tiejun.chen@intel.com> <1436420047-25356-7-git-send-email-tiejun.chen@intel.com> <55A3D5600200007800090330@mail.emea.novell.com> <55A4AE88.2000200@intel.com> <55A4F2270200007800090834@mail.emea.novell.com> <55A4EA54.60708@intel.com> <55A5138F0200007800090A71@mail.emea.novell.com> <55A5AF6F.1050305@intel.com> <55A5E122.7030203@intel.com> <55A6374E02000078000911EC@mail.emea.novell.com> <55A6210E.8080406@intel.com> <55A64386020000780009132E@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55A64386020000780009132E@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: Wei Liu , Ian Campbell , Stefano Stabellini , Andrew Cooper , Ian Jackson , "xen-devel@lists.xen.org" , Tiejun Chen , Keir Fraser List-Id: xen-devel@lists.xenproject.org On Wed, Jul 15, 2015 at 10:27 AM, Jan Beulich wrote: >>>> On 15.07.15 at 10:59, wrote: >> On 2015/7/15 16:34, Jan Beulich wrote: >>>>>> On 15.07.15 at 06:27, wrote: >>>> Furthermore, could we have this solution as follows? >>> >>> Yet more special casing code you want to add. I said no to this >>> model, and unless you can address the issue _without_ adding >>> a lot of special casing code, the answer will remain no (subject >> >> What about this? >> >> @@ -301,6 +301,19 @@ void pci_setup(void) >> pci_mem_start <<= 1; >> } >> >> + for ( i = 0; i < memory_map.nr_map ; i++ ) >> + { >> + uint64_t reserved_start, reserved_size; >> + reserved_start = memory_map.map[i].addr; >> + reserved_size = memory_map.map[i].size; >> + if ( check_overlap(pci_mem_start, pci_mem_end - pci_mem_start, >> + reserved_start, reserved_size) ) >> + { >> + printf("Reserved device memory conflicts current PCI memory.\n"); >> + BUG(); >> + } >> + } > > So what would the cure be if someone ran into this BUG() (other > than removing the device associated with the conflicting RMRR)? > Afaics such a guest would remain permanently unbootable, which > of course is not an option. Is not booting worse than what we have now -- which is, booting successfully but (probably) having issues due to MMIO ranges overlapping RMRRs? This patch series as a whole represents a lot of work and a lot of tangible improvements to the situation; and (unless the situation has changed) it's almost entirely acked apart from the MMIO placement part. If there is a simple way that we can change hvmloader so that most (or even many) VM/device combinations work properly for the 4.6 release, then I think it's worth considering. -George