[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [patch] more correct pfn_valid()
>-----Original Message----- >From: Ian Pratt [mailto:m+Ian.Pratt@xxxxxxxxxxxx] >Sent: Thursday, May 19, 2005 4:20 PM > > > For this part, I made a mistake to confuse domN and dom0. OK, >> for paravirtualized guest, there's actually no I/O range for >> domN, since the front driver in domN will do all things to >> communicate with backend in Dom0. But what about a driver >> domain which has access to physical device, thus need real >> I/O address? > >This works the same in dom0 and other domains: >IO machine addresses must be mapped into the kernel virtual address >space before you can use them. They are totally orthogonal to ram >addresses, and don't get mfn->pfn translated. > >Ian Thanks and that's make it clearer now. So just for last confirmation (sorry for tedious): 1. If driver domN's 'physical' memory is set as 0 - 4G continuously, and 2. When dom0 does PCI bus init, machine mmio space is set between [3G, 3G+512M] (Take a large range for example), Under above 2 conditions, current paravirtualized implementation can clearly handle between: 1. A normal access to 'physical' 3G + 4k address, and 2. Access to machine mmio address 3G + 4k of some physical device Is that assumption right? BTW, will that make some complexities for non-access operation, like comparison upon some address? Thanks a lot, - Kevin _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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