From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [RFC][PATCH 12/13] hvmloader/pci: skip reserved ranges Date: Fri, 15 May 2015 10:32:30 +0100 Message-ID: <5555D94E020000780007A794@mail.emea.novell.com> References: <1428657724-3498-1-git-send-email-tiejun.chen@intel.com> <1428657724-3498-13-git-send-email-tiejun.chen@intel.com> <553527940200007800073DA5@mail.emea.novell.com> <5555659C.4040104@intel.com> <5555AC10020000780007A59B@mail.emea.novell.com> <5555A185.4020200@intel.com> <5555C002020000780007A6AB@mail.emea.novell.com> <5555AB42.4020004@intel.com> <5555CAF0020000780007A6FB@mail.emea.novell.com> <5555BAB2.8000607@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5555BAB2.8000607@intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Tiejun Chen Cc: tim@xen.org, kevin.tian@intel.com, wei.liu2@citrix.com, ian.campbell@citrix.com, andrew.cooper3@citrix.com, Ian.Jackson@eu.citrix.com, xen-devel@lists.xen.org, stefano.stabellini@citrix.com, yang.z.zhang@intel.com List-Id: xen-devel@lists.xenproject.org >>> On 15.05.15 at 11:21, wrote: > On 2015/5/15 16:31, Jan Beulich wrote: >>>>> On 15.05.15 at 10:16, wrote: >>> On 2015/5/15 15:44, Jan Beulich wrote: >>>>>>> On 15.05.15 at 09:34, wrote: >>>>> So I think we may need to adjust pci_mem_start like this, >>>>> >>>>> @@ -301,6 +301,19 @@ void pci_setup(void) >>>>> pci_mem_start <<= 1; >>>>> } >>>>> >>>>> + /* Relocate PCI memory that overlaps reserved space, like RDM. */ >>>>> + for ( j = 0; j < memory_map.nr_map ; j++ ) >>>>> + { >>>>> + if ( memory_map.map[j].type != E820_RAM ) >>>>> + { >>>>> + reserved_end = memory_map.map[j].addr + memory_map.map[j].size; >>>>> + if ( check_overlap(pci_mem_start, pci_mem_end, >>>>> + memory_map.map[j].addr, >>>>> + memory_map.map[j].size) ) >>>>> + pci_mem_start -= memory_map.map[j].size >> PAGE_SHIFT; >>>>> + } >>>>> + } >>>>> + >>>>> if ( mmio_total > (pci_mem_end - pci_mem_start) ) >>>>> { >>>>> printf("Low MMIO hole not large enough for all devices," >>>>> >>>>> Right? >>>> >>>> I think that gets you in the right direction, but isn't enough, as it >>>> doesn't account for (unavoidable) gaps (BARs are always a power >>>> of 2 in size and accordingly aligned). >>> >>> Right. >>> >>> But as you see, we always take this action, >> PAGE_SHIFT, so this means >>> its always a sort of power of 2. >> >> No, certainly not. > > rdm start or size? Or anything else I'm missing? Both. How can an arbitrary value shifted right be PAGE_SHIFT be guaranteed to be a power of two? Jan