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From: "Xu, Quan" <quan.xu@intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "dario.faggioli@citrix.com" <dario.faggioli@citrix.com>,
	"Wu, Feng" <feng.wu@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [Patch v11 1/3] IOMMU: add a timeout parameter for device IOTLB invalidation
Date: Wed, 15 Jun 2016 02:55:17 +0000	[thread overview]
Message-ID: <945CA011AD5F084CBEA3E851C0AB28894B8E5D32@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <5750259102000078000F0D75@prv-mh.provo.novell.com>

On June 02, 2016 6:25 PM, Jan Beulich <JBeulich@suse.com> wrote:
> >>> On 01.06.16 at 11:05, <quan.xu@intel.com> wrote:
> > From: Quan Xu <quan.xu@intel.com>
> > v11: Change the timeout parameter from 'vtd_qi_timeout' to
> >     'iommu_dev_iotlb_timeout', which is not only for VT-d device
> >     IOTLB invalidation, but also for other IOMMU implementations.
> 
> This goes after the first --- separator.
> 

Got it. It should be:

---
v11:
       - ...
       - ...
---


> > --- a/docs/misc/xen-command-line.markdown
> > +++ b/docs/misc/xen-command-line.markdown
> > @@ -996,6 +996,15 @@ debug hypervisor only).
> >
> >  >> Enable IOMMU debugging code (implies `verbose`).
> >
> > +### iommu\_dev\_iotlb\_timeout
> > +> `= <integer>`
> > +
> > +> Default: `1`
> 
> So on v10 I had made clear that any timeout reduction from its current value
> is, for the ATS case, not acceptable, unless you have proof that this lower
> value will fit all past, present, and future devices. Otherwise we're risking a
> regression here.
> 

I really misunderstood the 'current value', which should be about 'DMAR_OPERATION_TIMEOUT MILLISECS(1000) ', instead of ' IOMMU_QI_TIMEOUT MILLISECS(1)' in my patch.
So the default is 1000.
 
> > --- a/xen/drivers/passthrough/vtd/qinval.c
> > +++ b/xen/drivers/passthrough/vtd/qinval.c
> > @@ -28,6 +28,8 @@
> >  #include "vtd.h"
> >  #include "extern.h"
> >
> > +#define IOMMU_QI_TIMEOUT MILLISECS(1)
> 
> May I suggest VTD_QI_TIMEOUT (but see also below)?
> 

Agreed. VTD_QI_TIMEOUT is a better one.

> > @@ -163,14 +165,21 @@ static int queue_invalidate_wait(struct iommu
> *iommu,
> >      /* Now we don't support interrupt method */
> >      if ( sw )
> >      {
> > +        s_time_t timeout;
> > +
> >          /* In case all wait descriptor writes to same addr with same data */
> > -        start_time = NOW();
> > +        timeout = flush_dev_iotlb ?
> > +                  (NOW() + iommu_dev_iotlb_timeout * MILLISECS(1)) :
> 
> MILLISECS(iommu_dev_iotlb_timeout)
> 
> > +                  (NOW() + IOMMU_QI_TIMEOUT);
> 
> Or really the whole expression should probably simply become
> 
>         timeout = NOW() + MILLISECS(flush_dev_iotlb ?
> iommu_dev_iotlb_timeout : VTD_QI_TIMEOUT);
> 
> (of course with VTD_QI_TIMEOUT having its MILLISECS() dropped, and
> suitably line wrapped).
> 


I prefer this later one.

Quan
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  reply	other threads:[~2016-06-15  2:55 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-01  9:05 [Patch v11 0/3] VT-d Device-TLB flush issue Xu, Quan
2016-06-01  9:05 ` [Patch v11 1/3] IOMMU: add a timeout parameter for device IOTLB invalidation Xu, Quan
2016-06-02 10:24   ` Jan Beulich
2016-06-15  2:55     ` Xu, Quan [this message]
2016-06-01  9:05 ` [Patch v11 2/3] vt-d: synchronize for Device-TLB flush one by one Xu, Quan
2016-06-02 10:49   ` Jan Beulich
2016-06-01  9:05 ` [Patch v11 3/3] vt-d: fix vt-d Device-TLB flush timeout issue Xu, Quan
2016-06-02 11:07   ` Jan Beulich
2016-06-16  8:42     ` Xu, Quan
2016-06-16  9:04       ` Jan Beulich
2016-06-17  6:08         ` Xu, Quan
2016-06-17  7:00           ` Jan Beulich
2016-06-17  8:15             ` Xu, Quan
2016-06-17  8:40               ` Jan Beulich
2016-06-22 15:54             ` Xu, Quan
2016-06-22 16:18               ` Jan Beulich
2016-06-23  2:08                 ` Xu, Quan

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