From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Auger Eric <eric.auger@redhat.com>
Cc: iommu@lists.linux-foundation.org,
LKML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
David Woodhouse <dwmw2@infradead.org>,
"Tian, Kevin" <kevin.tian@intel.com>,
Raj Ashok <ashok.raj@intel.com>, Yi Liu <yi.l.liu@intel.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v2 02/10] iommu/vt-d: Fix CPU and IOMMU SVM feature matching checks
Date: Tue, 19 Nov 2019 09:32:31 -0800 [thread overview]
Message-ID: <20191119093231.65fb3b3f@jacob-builder> (raw)
In-Reply-To: <3634dee5-3f9f-4618-951e-8bb5e4988223@redhat.com>
On Tue, 19 Nov 2019 09:02:26 +0100
Auger Eric <eric.auger@redhat.com> wrote:
> Hi Jacob,
>
> On 11/18/19 10:47 PM, Jacob Pan wrote:
> > On Mon, 18 Nov 2019 21:33:34 +0100
> > Auger Eric <eric.auger@redhat.com> wrote:
> >
> >> Hi Jacob,
> >>
> >> On 11/18/19 8:42 PM, Jacob Pan wrote:
> >>> The current code checks CPU and IOMMU feature set for SVM support
> >>> but the result is never stored nor used. Therefore, SVM can still
> >>> be used even when these checks failed.
> >> "SVM can still be used even when these checks failed". What were
> >> the consequences if it happened? Does it fix this cleanly now.
> >>>
> > The consequence is DMA cannot reach above 48-bit virtual address
> > range when CPU does 5-level and IOMMU can only do 4-level. With is
> > fix, svm_bind_mm will fail in the first place to prevent SVM use by
> > DMA.
> OK thank you for the clarification. Maybe this latter can be added in
> the commit message
> >
Yes, will do.
> [...]
> >> nit: is it really an error or just a warning?
> > I think it is an error in that there is an illegal configuration.
> > It is mostly for vIOMMU, we expect native HW should have these
> > features matched.
>
> OK
>
> Thanks
>
> Eric
> >
> [...]
> >> Besides,
> >> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> >>
> >> Thanks
> >>
> >> Eric
> >>
> >
> > [Jacob Pan]
> >
>
[Jacob Pan]
next prev parent reply other threads:[~2019-11-19 17:27 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-18 19:42 [PATCH v2 00/10] VT-d Native Shared virtual memory cleanup and fixes Jacob Pan
2019-11-18 19:42 ` [PATCH v2 01/10] iommu/vt-d: Introduce native SVM capable flag Jacob Pan
2019-11-18 20:33 ` Auger Eric
2019-11-18 21:48 ` Jacob Pan
2019-11-19 2:55 ` Lu Baolu
2019-11-19 17:06 ` Jacob Pan
2019-11-18 19:42 ` [PATCH v2 02/10] iommu/vt-d: Fix CPU and IOMMU SVM feature matching checks Jacob Pan
2019-11-18 20:33 ` Auger Eric
2019-11-18 21:47 ` Jacob Pan
2019-11-19 8:02 ` Auger Eric
2019-11-19 17:32 ` Jacob Pan [this message]
2019-11-18 19:42 ` [PATCH v2 03/10] iommu/vt-d: Reject SVM bind for failed capability check Jacob Pan
2019-11-18 20:55 ` Auger Eric
2019-11-18 19:42 ` [PATCH v2 04/10] iommu/vt-d: Match CPU and IOMMU paging mode Jacob Pan
2019-11-18 20:55 ` Auger Eric
2019-11-18 21:52 ` Jacob Pan
2019-11-19 3:06 ` Lu Baolu
2019-11-19 8:04 ` Auger Eric
2019-11-19 17:12 ` Jacob Pan
2019-11-18 19:42 ` [PATCH v2 05/10] iommu/vt-d: Avoid duplicated code for PASID setup Jacob Pan
2019-11-18 20:59 ` Auger Eric
2019-11-18 19:42 ` [PATCH v2 06/10] iommu/vt-d: Fix off-by-one in PASID allocation Jacob Pan
2019-11-18 21:00 ` Auger Eric
2019-11-18 19:42 ` [PATCH v2 07/10] iommu/vt-d: Replace Intel specific PASID allocator with IOASID Jacob Pan
2019-11-18 21:11 ` Auger Eric
2019-11-18 22:16 ` Jacob Pan
2019-11-18 19:42 ` [PATCH v2 08/10] iommu/vt-d: Fix PASID cache flush Jacob Pan
2019-11-18 21:19 ` Auger Eric
2019-11-18 23:38 ` Jacob Pan
2019-11-18 19:42 ` [PATCH v2 09/10] iommu/vt-d: Avoid sending invalid page response Jacob Pan
2019-11-18 21:26 ` Auger Eric
2019-11-18 19:42 ` [PATCH v2 10/10] iommu/vt-d: Misc macro clean up for SVM Jacob Pan
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