Messages in this thread | | | Subject | Re: [PATCH] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive | From | Yongji Xie <> | Date | Tue, 3 May 2016 15:36:05 +0800 |
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On 2016/5/3 14:11, Tian, Kevin wrote:
>> From: Yongji Xie [mailto:xyjxie@linux.vnet.ibm.com] >> Sent: Tuesday, May 03, 2016 1:52 PM >> >>>> + >>>> + if (!(res->start & ~PAGE_MASK)) { >>>> + /* >>>> + * Add shadow resource for sub-page bar whose mmio >>>> + * page is exclusive in case that hot-add device's >>>> + * bar is assigned into the mem hole. >>>> + */ >>>> + shadow_res = kzalloc(sizeof(*shadow_res), GFP_KERNEL); >>>> + shadow_res->resource.start = res->end + 1; >>>> + shadow_res->resource.end = res->start + PAGE_SIZE - 1; >>> What about res->start not page aligned so you end up still having >>> a portion before res->start not exclusively reserved? >> Do you mean add a 'dummy' resource to reserve the portion >> before res->start if res->start not page aligned? >> >> But would it happen that there is a mem hole in the portion >> before res->start? The resource should have been assigned >> into the hole at the beginning. >> > Just a quick thought. Another device might occupy that range > before initializing this device, and then 'another device' is hot > removed later... > > Thanks > Kevin
That's a good point! I will add support for this case in v2.
Thanks, Yongji
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