[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 Wed, Apr 12, 2017 at 02:57:23AM -0600, 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? As to No. I have confirmed this with VT-d architect that VT-d hardware doesn't update IRTEs. For posted format, VT-d hardware will atomically update Posted Interrupt Descriptor, an address recorded in posted format IRTE. >software not updating, with there not being any synchronization >clearly visible around here, I'm afraid this also needs expanding >on (in the commit message at least, not necessarily in the >comment). Will do. > >> + * If a caller want an atomic update from the views of VT-d > >wants > >Also what do you mean by "from the views of VT-d"? OK. will fix this too. Do you mean it is (and should be) atomic from software's view , so these words are redundant. Thanks Chao _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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