From: "Xu, Quan" <quan.xu@intel.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Jan Beulich <jbeulich@suse.com>
Cc: "dario.faggioli@citrix.com" <dario.faggioli@citrix.com>
Subject: Re: [PATCH v3 02/10] IOMMU: handle IOMMU mapping and unmapping failures
Date: Wed, 4 May 2016 11:49:41 +0000 [thread overview]
Message-ID: <945CA011AD5F084CBEA3E851C0AB28894B8A8B38@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D15F84398D@SHSMSX101.ccr.corp.intel.com>
On May 04, 2016 9:29 AM, Tian, Kevin <kevin.tian@intel.com> wrote:
> > From: Quan Xu
> > Sent: Friday, April 29, 2016 5:25 PM
> >
> > Treat IOMMU mapping and unmapping failures as a fatal to the domain
> > (with the exception of the hardware domain).
> >
> > If IOMMU mapping and unmapping failed, crash the domain (with the
> > exception of the hardware domain) and propagate the error up to the
> > call trees.
> >
> > Signed-off-by: Quan Xu <quan.xu@intel.com>
> > Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> >
> > CC: Jan Beulich <jbeulich@suse.com>
> > ---
> > xen/drivers/passthrough/iommu.c | 30 ++++++++++++++++++++++++++++--
> > 1 file changed, 28 insertions(+), 2 deletions(-)
> >
> > diff --git a/xen/drivers/passthrough/iommu.c
> > b/xen/drivers/passthrough/iommu.c index b64676f..a0003ac 100644
> > --- a/xen/drivers/passthrough/iommu.c
> > +++ b/xen/drivers/passthrough/iommu.c
> > @@ -243,21 +243,47 @@ int iommu_map_page(struct domain *d,
> unsigned
> > long gfn, unsigned long mfn,
> > unsigned int flags) {
> > struct hvm_iommu *hd = domain_hvm_iommu(d);
> > + int rc;
> >
> > if ( !iommu_enabled || !hd->platform_ops )
> > return 0;
> >
> > - return hd->platform_ops->map_page(d, gfn, mfn, flags);
> > + rc = hd->platform_ops->map_page(d, gfn, mfn, flags);
> > +
> > + if ( rc )
> > + {
> > + if ( is_hardware_domain(d) )
> > + printk(XENLOG_ERR
> > + "iommu_map_page: IOMMU mapping gfn %#lx mfn %#lx
> > + failed for
> > dom%d.",
> > + gfn, mfn, d->domain_id);
> > + else
> > + domain_crash(d);
> > + }
>
> It makes sense to print error messages for all domains, and then selectively
> crash domain:
>
> printk(XENLOG_ERR ...);
> if ( !is_hardware_domain(d) )
> domain_crash(d);
>
But Jan said,
..
if ( is_hardware_domain() )
printk();
else
domain_crash();
..
is the better approach.
I remain neutral for this point. I think this is not a technical problem, but a matter of preference.
This gap is subject to preventing spamming the log.
For iommu_map_page(), I think Kevin's suggestion is better, much more information for the crash domain,
And also won't spam the log as we stop mapping against any error.
For iommu_unmap_page(),IOMMU unmapping should perhaps continue despite an error, in an attempt
to do best effort cleanup. Then, Kevin's suggestion may spam the log.
Quan
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next prev parent reply other threads:[~2016-05-04 11:49 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-29 9:25 [PATCH v3 00/10] Check VT-d Device-TLB flush error Quan Xu
2016-04-29 9:25 ` [PATCH v3 01/10] vt-d: fix the IOMMU flush issue Quan Xu
2016-05-04 1:26 ` Tian, Kevin
2016-05-04 12:09 ` Xu, Quan
2016-05-04 13:51 ` Jan Beulich
2016-05-04 15:03 ` Xu, Quan
2016-04-29 9:25 ` [PATCH v3 02/10] IOMMU: handle IOMMU mapping and unmapping failures Quan Xu
2016-05-04 1:28 ` Tian, Kevin
2016-05-04 11:49 ` Xu, Quan [this message]
2016-05-04 13:44 ` Jan Beulich
2016-05-05 1:47 ` Xu, Quan
2016-04-29 9:25 ` [PATCH v3 03/10] IOMMU/MMU: enhance the call trees of IOMMU unmapping and mapping Quan Xu
2016-05-04 1:45 ` Tian, Kevin
2016-05-04 8:40 ` Jan Beulich
2016-05-04 9:13 ` Xu, Quan
2016-05-04 9:28 ` Jan Beulich
2016-05-05 0:38 ` Tian, Kevin
2016-05-04 13:48 ` George Dunlap
2016-05-05 6:53 ` Xu, Quan
2016-05-05 11:02 ` George Dunlap
2016-05-06 2:40 ` Xu, Quan
2016-04-29 9:25 ` [PATCH v3 04/10] vt-d: propagate IOMMU Device-TLB flush error up to IOMMU unmapping Quan Xu
2016-04-29 9:25 ` [PATCH v3 05/10] vt-d: propagate IOMMU Device-TLB flush error up to IOMMU mapping Quan Xu
2016-04-29 9:25 ` [PATCH v3 06/10] propagate IOMMU Device-TLB flush error up to iommu_iotlb_flush{, _all} (top level ones) Quan Xu
2016-04-29 9:25 ` [PATCH v3 07/10] IOMMU: propagate IOMMU Device-TLB flush error up to iommu_iotlb_flush{, _all} (leaf ones) Quan Xu
2016-05-04 1:54 ` Tian, Kevin
2016-04-29 9:25 ` [PATCH v3 08/10] vt-d/ept: propagate IOMMU Device-TLB flush error up to EPT update Quan Xu
2016-05-04 1:56 ` Tian, Kevin
2016-04-29 9:25 ` [PATCH v3 09/10] IOMMU: propagate IOMMU Device-TLB flush error up to IOMMU suspending Quan Xu
2016-05-04 1:59 ` Tian, Kevin
2016-05-04 2:14 ` Xu, Quan
2016-05-04 8:42 ` Jan Beulich
2016-05-04 8:59 ` Xu, Quan
2016-05-05 10:18 ` Xu, Quan
2016-05-06 7:02 ` Jan Beulich
2016-05-06 7:20 ` Xu, Quan
2016-04-29 9:25 ` [PATCH v3 10/10] vt-d: propagate error up to ME phantom function mapping and unmapping Quan Xu
2016-05-04 2:02 ` Tian, Kevin
2016-05-04 2:19 ` Xu, Quan
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