From: "Jan Beulich" <JBeulich@suse.com>
To: Quan Xu <quan.xu@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Feng Wu <feng.wu@intel.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Liu Jinsong <jinsong.liu@alibaba-inc.com>,
Dario Faggioli <dario.faggioli@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Jun Nakajima <jun.nakajima@intel.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Keir Fraser <keir@xen.org>
Subject: Re: [PATCH 1/2] IOMMU/MMU: Adjust top level functions for VT-d Device-TLB flush error.
Date: Thu, 24 Mar 2016 08:37:27 -0600 [thread overview]
Message-ID: <56F409B702000078000E02D0@prv-mh.provo.novell.com> (raw)
In-Reply-To: <945CA011AD5F084CBEA3E851C0AB28894B86B54F@SHSMSX101.ccr.corp.intel.com>
>>> On 24.03.16 at 15:12, <quan.xu@intel.com> wrote:
> On March 24, 2016 5:59pm, <JBeulich@suse.com> wrote:
>> >>> On 24.03.16 at 10:02, <quan.xu@intel.com> wrote:
>> > On March 18, 2016 5:49pm, <JBeulich@suse.com> wrote:
>
>
>> > 3. For iommu_{,un}map_page(), we'd better fix it as a normal error,
>> > as the error is not only from iommu flush, .e.g, '-ENOMEM'.
>> > So, we need to {,un}map from the IOMMU, return an error, and roll
>> > back the failed operation( .e.g, unmap EPT).
>>
>> Well, if that possible in a provably correct way, then sure. But be clear - when
>> the failure occurs while unmapping, unmapping the EPT entry obviously can't be
>> the solution,
>
> I hope we discuss about the same point as bellow?:
> ept_set_entry()
> {
> ....
> if ( iommu_flags )
> for ( i = 0; i < (1 << order); i++ )
> iommu_map_page(d, gfn + i, mfn_x(mfn) + i, iommu_flags);
> else
> for ( i = 0; i < (1 << order); i++ )
> iommu_unmap_page(d, gfn + i);
> ....
> }
>
>
>> you'd need a true roll back.
>
> Does it refer to as:
> If the old entry is present, we need to write back the old entry?
Yes, but that's not as simple as it sounds: You also need to take
care of the splitting of super pages which may have occurred.
Jan
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next prev parent reply other threads:[~2016-03-24 14:37 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-17 6:54 [PATCH 0/2] Check VT-d Device-TLB flush error Quan Xu
2016-03-17 6:54 ` [PATCH 1/2] IOMMU/MMU: Adjust top level functions for " Quan Xu
2016-03-17 7:32 ` Tian, Kevin
2016-03-17 7:58 ` Jan Beulich
2016-03-17 8:00 ` Tian, Kevin
2016-03-17 12:30 ` George Dunlap
2016-03-17 12:33 ` George Dunlap
2016-03-18 3:19 ` Xu, Quan
2016-03-18 8:09 ` Jan Beulich
2016-03-24 6:45 ` Xu, Quan
2016-03-18 7:54 ` Xu, Quan
2016-03-18 8:19 ` Jan Beulich
2016-03-18 9:09 ` Xu, Quan
2016-03-18 9:29 ` Jan Beulich
2016-03-18 9:38 ` Dario Faggioli
2016-03-18 9:48 ` Jan Beulich
2016-03-21 6:18 ` Tian, Kevin
2016-03-21 12:22 ` Jan Beulich
2016-03-24 9:02 ` Xu, Quan
2016-03-24 9:58 ` Jan Beulich
2016-03-24 14:12 ` Xu, Quan
2016-03-24 14:37 ` Jan Beulich [this message]
2016-03-17 17:14 ` Jan Beulich
2016-03-28 3:33 ` Xu, Quan
2016-03-29 7:20 ` Jan Beulich
2016-03-30 2:28 ` Xu, Quan
2016-03-30 2:35 ` Xu, Quan
2016-03-30 8:05 ` Jan Beulich
2016-03-17 6:54 ` [PATCH 2/2] IOMMU/MMU: Adjust low " Quan Xu
2016-03-17 7:37 ` Tian, Kevin
2016-03-18 2:30 ` Xu, Quan
2016-03-18 8:06 ` Jan Beulich
2016-03-21 5:01 ` Tian, Kevin
2016-03-17 15:31 ` George Dunlap
2016-03-18 6:57 ` Xu, Quan
2016-03-18 10:20 ` Jan Beulich
2016-03-25 9:27 ` Xu, Quan
2016-03-29 7:36 ` Jan Beulich
2016-04-11 3:09 ` Xu, Quan
2016-04-11 3:27 ` Xu, Quan
2016-04-11 16:34 ` Jan Beulich
2016-04-12 1:09 ` Xu, Quan
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