From: "Tian, Kevin" <kevin.tian@intel.com>
To: "Xu, Quan" <quan.xu@intel.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Cc: "dario.faggioli@citrix.com" <dario.faggioli@citrix.com>,
"Wu, Feng" <feng.wu@intel.com>,
"jbeulich@suse.com" <jbeulich@suse.com>
Subject: Re: [PATCH v7 2/2] VT-d: Fix vt-d Device-TLB flush timeout issue
Date: Mon, 21 Mar 2016 03:27:23 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D15F7EF016@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <945CA011AD5F084CBEA3E851C0AB28894B86785F@SHSMSX101.ccr.corp.intel.com>
> From: Xu, Quan
> Sent: Friday, March 18, 2016 8:22 PM
>
> > > +int dev_invalidate_iotlb_sync(struct iommu *iommu, u16 did,
> > > + u16 seg, u8 bus, u8 devfn) {
> > > + struct qi_ctrl *qi_ctrl = iommu_qi_ctrl(iommu);
> > > + int rc = 0;
> > > +
> > > + if ( qi_ctrl->qinval_maddr )
> > > + {
> > > + rc = queue_invalidate_wait(iommu, 0, 1, 1);
> > > + if ( rc == -ETIMEDOUT )
> > > + dev_invalidate_iotlb_timeout(iommu, did, seg, bus, devfn);
> > > + }
> > > +
> > > + return rc;
> > > +}
> > > +
> >
> > Is this function a temporary one which will be removed later once we can
> > handle timeout for all types of flushes (at that time suppose this logic will be
> > reflected in invalidate_sync directly)?
> >
> No, it's not a temporary one.
> dev_invalidate_iotlb_sync -- for Device-TLB invalidation sync, as we need SBDF to indicate
> which device flush timed out.
> invalidate_sync -- for VT-d iotlb/iec/context invalidation sync.
Thanks. I recalled it. Once you defined some INVALID seg/bus/devfn to
reuse same interface, and then the suggestion is to go with different
interfaces.:-)
>
>
> > > static void queue_invalidate_iec(struct iommu *iommu, u8 granu, u8
> > > im, u16 iidx) {
> > > unsigned long flags;
> > > @@ -342,8 +393,6 @@ static int flush_iotlb_qi(
> > >
> > > if ( qi_ctrl->qinval_maddr != 0 )
> > > {
> > > - int rc;
> > > -
> > > /* use queued invalidation */
> > > if (cap_write_drain(iommu->cap))
> > > dw = 1;
> > > @@ -353,11 +402,17 @@ static int flush_iotlb_qi(
> > > queue_invalidate_iotlb(iommu,
> > > type >>
> > DMA_TLB_FLUSH_GRANU_OFFSET, dr,
> > > dw, did, size_order, 0, addr);
> > > +
> > > + /*
> > > + * Before Device-TLB invalidation we need to synchronize
> > > + * invalidation completions with hardware.
> > > + */
> > > + ret = invalidate_sync(iommu);
> > > + if ( ret )
> > > + return ret;
> > > +
> > > if ( flush_dev_iotlb )
> > > ret = dev_invalidate_iotlb(iommu, did, addr, size_order, type);
> > > - rc = invalidate_sync(iommu);
> > > - if ( !ret )
> > > - ret = rc;
> >
> > Current change looks not consistent. For IOMMU iotlb flush, we have
> > invalidate_sync out of invalidate operation, however below...
> >
>
> Now, does it still look not consistent?
>
Yes, still inconsistent. As I said, you put invalidation sync within
dev_invalidate_iotlb, while for all other IOMMU invalidations the
sync is put after. Below would be consistent then:
if ( flush_dev_iotlb )
ret = dev_invalidate_iotlb(iommu, did, addr, size_order, type);
rc = dev_invalidate_iotlb_sync(...);
if ( !ret )
ret = rc;
Thanks
Kevin
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next prev parent reply other threads:[~2016-03-21 3:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-17 7:12 [PATCH v7 0/2] VT-d Device-TLB flush issue Quan Xu
2016-03-17 7:12 ` [PATCH v7 1/2] VT-d: Reduce spin timeout to 1ms, which can be boot-time changed Quan Xu
2016-03-17 7:45 ` Tian, Kevin
2016-03-17 8:11 ` Xu, Quan
2016-03-17 8:13 ` Jan Beulich
2016-03-17 8:17 ` Xu, Quan
2016-03-17 7:12 ` [PATCH v7 2/2] VT-d: Fix vt-d Device-TLB flush timeout issue Quan Xu
2016-03-17 8:17 ` Tian, Kevin
2016-03-17 9:43 ` Jan Beulich
2016-03-17 11:13 ` Tian, Kevin
2016-03-17 11:30 ` Xu, Quan
2016-03-17 11:32 ` Tian, Kevin
2016-03-17 11:33 ` Jan Beulich
2016-03-18 12:21 ` Xu, Quan
2016-03-21 3:27 ` Tian, Kevin [this message]
2016-03-23 2:12 ` Xu, Quan
2016-03-23 3:29 ` Xu, Quan
2016-03-23 5:36 ` Tian, Kevin
2016-03-23 5:39 ` Xu, Quan
2016-03-18 11:18 ` Jan Beulich
2016-03-18 11:31 ` Xu, Quan
2016-03-18 13:35 ` Jan Beulich
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