On 04/13/2010 02:58 PM, H. Peter Anvin wrote: > On 04/13/2010 02:42 PM, Yinghai wrote: >> On 04/13/2010 02:18 PM, H. Peter Anvin wrote: >>> On 04/13/2010 02:11 PM, Yinghai wrote: >>>>> >>>>> I guess the real question (which I haven't looked at myself) is if the >>>>> E820_RESERVED -> BUSY will cause an explicitly assigned BAR from being >>>>> moved. That's bad, not so much for this particular range, but from BARs >>>>> which may be assigned by SMM. Hacking that up in a simulator >>>>> (Qemu/Bochs) and testing it is probably on the to do list... >>>> >>>> no, if some device BAR fall in that range, it should still use that range, and will not be relocated. >>>> >>>> will update the change log. >>>> >>> >>> Good, that's what we want. >> >> the driver for that device later can not use pci_request_region(). because that region is BUSY already. >> > > That's not good (in general - for devices in this particular range it's > not such a big deal, but it is potentially really bad for devices marked > reserved for them not to be moved.) > > We have talked about a need to resolve this before. current code for mmio that is just below 4g, if some PCI BAR use that range, and those range is falling into E820_RESERVED, those range still can be claimed, but driver can not use pci_request_region() later. So We still 1. rely that BIOS does not reserve the [0xa0000, 0xe0000) 2. kernel only reserve the range when we make sure these is legacy device on that range. YH -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
