[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] VT-d: correct a comment and remove useless if() statement
>>> On 12.04.17 at 12:58, <andrew.cooper3@xxxxxxxxxx> wrote: > On 12/04/17 09:57, Jan Beulich wrote: >>>>> On 12.04.17 at 02:04, <chao.gao@xxxxxxxxx> wrote: >>> --- a/xen/drivers/passthrough/vtd/intremap.c >>> +++ b/xen/drivers/passthrough/vtd/intremap.c >>> @@ -200,8 +200,9 @@ static void update_irte(struct iommu *iommu, struct >>> iremap_entry *entry, >>> else >>> { >>> /* >>> - * If the caller requests an atomic update but we can't meet it, >>> - * a bug will be raised. >>> + * VT-d hardware doesn't update IRTEs behind us, nor the software. >> Hmm, so far I was under the impression that in posted mode the >> IRTE could be updated by hardware. Is that not the case? > > No. The IRTE is just a translation structure, so conceptually similar > to a pagetable. Not the best analogy, as page tables do get written by the CPU. > With posted interrupts, it is the PI block in memory (referenced by the > IRTE) which gets written to by hardware. Okay, then I apparently misremember Feng saying otherwise in the early stages of the original series. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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