From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org, Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Raj Ashok <ashok.raj@intel.com>, Yi Liu <yi.l.liu@intel.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush
Date: Tue, 24 Mar 2020 08:31:25 -0700 [thread overview]
Message-ID: <20200324083125.27b78594@jacob-builder> (raw)
In-Reply-To: <06c9751a-417d-3c32-65af-0788593f811a@linux.intel.com>
On Sat, 21 Mar 2020 09:32:45 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:
> On 2020/3/21 0:20, Jacob Pan wrote:
> > On Fri, 20 Mar 2020 21:45:26 +0800
> > Lu Baolu <baolu.lu@linux.intel.com> wrote:
> >
> >> On 2020/3/20 12:32, Jacob Pan wrote:
> >>> IOTLB flush already included in the PASID tear down process. There
> >>> is no need to flush again.
> >>
> >> It seems that intel_pasid_tear_down_entry() doesn't flush the pasid
> >> based device TLB?
> >>
> > I saw this code in intel_pasid_tear_down_entry(). Isn't the last
> > line flush the devtlb? Not in guest of course since the passdown
> > tlb flush is inclusive.
> >
> > pasid_cache_invalidation_with_pasid(iommu, did, pasid);
> > iotlb_invalidation_with_pasid(iommu, did, pasid);
> >
> > /* Device IOTLB doesn't need to be flushed in caching mode.
> > */ if (!cap_caching_mode(iommu->cap))
> > devtlb_invalidation_with_pasid(iommu, dev, pasid);
> >
>
> But devtlb_invalidation_with_pasid() doesn't do the right thing, it
> flushes the device tlb, instead of pasid-based device tlb.
>
Hmm, you are right. But the function name is misleading, pasid argument
is not used, is there a reason why?
This is used for PASID based device IOTLB flush, right?
> static void
> devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
> struct device *dev, int pasid)
> {
> struct device_domain_info *info;
> u16 sid, qdep, pfsid;
>
> info = dev->archdata.iommu;
> if (!info || !info->ats_enabled)
> return;
>
> sid = info->bus << 8 | info->devfn;
> qdep = info->ats_qdep;
> pfsid = info->pfsid;
>
> qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 -
> VTD_PAGE_SHIFT);
> }
>
> Best regards,
> baolu
>
> >> Best regards,
> >> baolu
> >>
> >>>
> >>> Cc: Lu Baolu <baolu.lu@linux.intel.com>
> >>> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> >>> ---
> >>> drivers/iommu/intel-svm.c | 6 ++----
> >>> 1 file changed, 2 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> >>> index 8f42d717d8d7..1483f1845762 100644
> >>> --- a/drivers/iommu/intel-svm.c
> >>> +++ b/drivers/iommu/intel-svm.c
> >>> @@ -268,10 +268,9 @@ static void intel_mm_release(struct
> >>> mmu_notifier *mn, struct mm_struct *mm)
> >>> * *has* to handle gracefully without affecting other
> >>> processes. */
> >>> rcu_read_lock();
> >>> - list_for_each_entry_rcu(sdev, &svm->devs, list) {
> >>> + list_for_each_entry_rcu(sdev, &svm->devs, list)
> >>> intel_pasid_tear_down_entry(svm->iommu,
> >>> sdev->dev, svm->pasid);
> >>> - intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
> >>> - }
> >>> +
> >>> rcu_read_unlock();
> >>>
> >>> }
> >>> @@ -731,7 +730,6 @@ int intel_svm_unbind_mm(struct device *dev,
> >>> int pasid)
> >>> * large and has to be physically
> >>> contiguous. So it's
> >>> * hard to be as defensive as we might
> >>> like. */ intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
> >>> - intel_flush_svm_range_dev(svm, sdev, 0,
> >>> -1, 0); kfree_rcu(sdev, rcu);
> >>>
> >>> if (list_empty(&svm->devs)) {
> >>>
> >
> > [Jacob Pan]
> >
[Jacob Pan]
next prev parent reply other threads:[~2020-03-24 15:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 4:32 [PATCH 0/3] Misc bug fixes for VT-d SVM Jacob Pan
2020-03-20 4:32 ` [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush Jacob Pan
2020-03-20 13:45 ` Lu Baolu
2020-03-20 16:20 ` Jacob Pan
2020-03-21 1:32 ` Lu Baolu
2020-03-24 15:31 ` Jacob Pan [this message]
2020-03-25 0:48 ` Lu Baolu
2020-03-20 4:32 ` [PATCH 2/3] iommu/vt-d: Fix mm reference leak Jacob Pan
2020-03-20 13:49 ` Lu Baolu
2020-03-20 4:32 ` [PATCH 3/3] iommu/vt-d: Add build dependency on IOASID Jacob Pan
2020-03-20 13:57 ` Lu Baolu
2020-03-27 10:04 ` [PATCH 0/3] Misc bug fixes for VT-d SVM Joerg Roedel
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