From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>
Cc: "Raj, Ashok" <ashok.raj@intel.com>,
"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Sun, Yi Y" <yi.y.sun@intel.com>,
"peterx@redhat.com" <peterx@redhat.com>,
Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: RE: [PATCH v4 04/12] iommu/vt-d: Add 256-bit invalidation descriptor support
Date: Thu, 8 Nov 2018 03:49:16 +0000 [thread overview]
Message-ID: <A2975661238FB949B60364EF0F2C257439D604DF@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <a6e43ddd-0889-4a4a-b908-993db28c6d87@linux.intel.com>
Hi,
> From: Lu Baolu [mailto:baolu.lu@linux.intel.com]
> Sent: Thursday, November 8, 2018 10:17 AM
> Subject: Re: [PATCH v4 04/12] iommu/vt-d: Add 256-bit invalidation descriptor
> support
>
> Hi Yi,
>
> On 11/7/18 2:07 PM, Liu, Yi L wrote:
> > Hi Baolu,
> >
> >> From: Lu Baolu [mailto:baolu.lu@linux.intel.com]
> >> Sent: Monday, November 5, 2018 1:32 PM
> >
> > [...]
> >
> >> ---
> >> drivers/iommu/dmar.c | 83 +++++++++++++++++++----------
> >> drivers/iommu/intel-svm.c | 76 ++++++++++++++++----------
> >> drivers/iommu/intel_irq_remapping.c | 6 ++-
> >> include/linux/intel-iommu.h | 9 +++-
> >> 4 files changed, 115 insertions(+), 59 deletions(-)
> >>
> >> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index
> >> d9c748b6f9e4..ec10427b98ac 100644
> >> --- a/drivers/iommu/dmar.c
> >> +++ b/drivers/iommu/dmar.c
> >> @@ -1160,6 +1160,7 @@ static int qi_check_fault(struct intel_iommu
> >> *iommu, int
> >> index)
> >> int head, tail;
> >> struct q_inval *qi = iommu->qi;
> >> int wait_index = (index + 1) % QI_LENGTH;
> >> + int shift = qi_shift(iommu);
> >>
> >> if (qi->desc_status[wait_index] == QI_ABORT)
> >> return -EAGAIN;
> >> @@ -1173,13 +1174,15 @@ static int qi_check_fault(struct intel_iommu
> >> *iommu, int index)
> >> */
> >> if (fault & DMA_FSTS_IQE) {
> >> head = readl(iommu->reg + DMAR_IQH_REG);
> >> - if ((head >> DMAR_IQ_SHIFT) == index) {
> >> + if ((head >> shift) == index) {
> >> + struct qi_desc *desc = qi->desc + head;
> >> +
> >> pr_err("VT-d detected invalid descriptor: "
> >> "low=%llx, high=%llx\n",
> >> - (unsigned long long)qi->desc[index].low,
> >> - (unsigned long long)qi->desc[index].high);
> >> - memcpy(&qi->desc[index], &qi->desc[wait_index],
> >> - sizeof(struct qi_desc));
> >> + (unsigned long long)desc->qw0,
> >> + (unsigned long long)desc->qw1);
> >
> > Still missing qw2 and qw3. May make the print differ based on if smts is configed.
>
> qw2 and qw3 are reserved from software point of view. We don't need to print it for
> information.
But for Scalable mode, it should be valid?
>
> >
> >> + memcpy(desc, qi->desc + (wait_index << shift),
> >
> > Would "memcpy(desc, (unsigned long long) (qi->desc + (wait_index <<
> > shift)," be more safe?
>
> Can that be compiled? memcpy() requires a "const void *" for the second parameter.
> By the way, why it's safer with this casting?
This is just an example. My point is the possibility that "qi->desc + (wait_index << shift)"
would be treated as "qi->desc plus (wait_index << shift)*sizeof(*qi->desc)". Is it possible
for kernel build?
Regards,
Yi Liu
next prev parent reply other threads:[~2018-11-08 3:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-05 5:31 [PATCH v4 00/12] iommu/vt-d: Add scalable mode support Lu Baolu
2018-11-05 5:31 ` [PATCH v4 01/12] iommu/vt-d: Enumerate the scalable mode capability Lu Baolu
2018-11-05 5:31 ` [PATCH v4 02/12] iommu/vt-d: Manage scalalble mode PASID tables Lu Baolu
2018-11-05 5:31 ` [PATCH v4 03/12] iommu/vt-d: Move page table helpers into header Lu Baolu
2018-11-07 7:41 ` Liu, Yi L
2018-11-05 5:31 ` [PATCH v4 04/12] iommu/vt-d: Add 256-bit invalidation descriptor support Lu Baolu
2018-11-07 6:07 ` Liu, Yi L
2018-11-08 2:16 ` Lu Baolu
2018-11-08 3:49 ` Liu, Yi L [this message]
2018-11-08 5:24 ` Lu Baolu
2018-11-08 5:45 ` Liu, Yi L
2018-11-08 6:14 ` Lu Baolu
2018-11-08 7:20 ` Liu, Yi L
2018-11-09 1:39 ` Lu Baolu
2018-11-09 2:59 ` Liu, Yi L
2018-11-08 5:48 ` Liu, Yi L
2018-11-08 6:15 ` Lu Baolu
2018-11-05 5:31 ` [PATCH v4 05/12] iommu/vt-d: Reserve a domain id for FL and PT modes Lu Baolu
2018-11-07 6:55 ` Liu, Yi L
2018-11-08 2:22 ` Lu Baolu
2018-11-05 5:31 ` [PATCH v4 06/12] iommu/vt-d: Add second level page table interface Lu Baolu
2018-11-07 7:13 ` Liu, Yi L
2018-11-08 2:27 ` Lu Baolu
2018-11-08 4:00 ` Liu, Yi L
2018-11-05 5:31 ` [PATCH v4 07/12] iommu/vt-d: Setup pasid entry for RID2PASID support Lu Baolu
2018-11-05 5:31 ` [PATCH v4 08/12] iommu/vt-d: Pass pasid table to context mapping Lu Baolu
2018-11-07 7:25 ` Liu, Yi L
2018-11-08 2:34 ` Lu Baolu
2018-11-05 5:31 ` [PATCH v4 09/12] iommu/vt-d: Setup context and enable RID2PASID support Lu Baolu
2018-11-05 5:31 ` [PATCH v4 10/12] iommu/vt-d: Add first level page table interface Lu Baolu
2018-11-07 7:34 ` Liu, Yi L
2018-11-05 5:31 ` [PATCH v4 11/12] iommu/vt-d: Shared virtual address in scalable mode Lu Baolu
2018-11-05 7:15 ` Christoph Hellwig
2018-11-05 7:17 ` Lu Baolu
2018-11-05 5:31 ` [PATCH v4 12/12] iommu/vt-d: Remove deferred invalidation Lu Baolu
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