[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v9 11/17] vt-d: Add API to update IRTE when VT-d PI is used
>>> On 24.11.15 at 08:56, <kevin.tian@xxxxxxxxx> wrote: >> From: Wu, Feng >> Sent: Tuesday, November 24, 2015 3:54 PM >> > From: Tian, Kevin >> > Sent: Tuesday, November 24, 2015 3:45 PM >> > > + /* Setup/Update interrupt remapping table entry. */ >> > > + setup_posted_irte(&new_ire, &old_ire, pi_desc, gvec); >> > > + ret = cmpxchg16b(p, &old_ire, &new_ire); >> > > + >> > > + /* >> > > + * In the above, we use cmpxchg16 to atomically update the 128-bit >> > IRTE, >> > > + * and the hardware cannot update the IRTE behind us, so the return >> > value >> > >> > hardware can DEFINITELY update IRTE behind us, right? e.g. after the IRTE >> > entry >> > is fully up, when interrupt is posted, etc. Here you might mean hardware >> > cannot >> > update the IRTE at this point? >> >> Yes, you description above is more accurate. But why hardware needs to >> update IRTE when interrupt is posted? I think it needs to update the >> posted interrupt descriptor when posting an interrupt, not the IRTE, >> right? > > sorry mess IRTE and posted descriptor together. but using "behind" > is still not accurate to state your point here. :-) Well, "behind us" and "behind our back" seem to mean mostly the same to me. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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