> -----Original Message----- > From: linux-kernel-ow...@vger.kernel.org [mailto:linux-kernel- > ow...@vger.kernel.org] On Behalf Of Joerg Roedel > Sent: Thursday, October 15, 2015 10:24 PM > To: Wu, Feng <feng...@intel.com> > Cc: io...@lists.linux-foundation.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH] iommu/vt-d: Use cmpxchg16b to update posted format > IRTE atomically > > On Thu, Oct 15, 2015 at 10:19:11AM +0800, Feng Wu wrote: > > If IRTE is in posted format, the 'pda' field goes across the 64-bit > > boundary, we need use cmpxchg16b to atomically update it. We only > > expose posted-interrupt when X86_FEATURE_CX16 is supported and use > > to update it atomically. > > + > > + ret = cmpxchg_double(&irte->low, &irte->high, > > + irte->low, irte->high, > > + irte_modified->low, irte_modified->high); > > + /* > > + * We use cmpxchg16 to atomically update the 128-bit IRTE, > > + * and it cannot be updated by the hardware or other > processors > > + * behind us, so the return value of cmpxchg16 should be the > > + * same as the old value. > > + */ > > + BUG_ON(!ret); > > Changed this to a WARN_ON, otherwise applied.
Thanks a lot, Joerg! Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
