From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Baolu Lu <baolu.lu@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Nicolin Chen <nicolinc@nvidia.com>,
"Liu, Yi L" <yi.l.liu@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/9] iommu: Add common code to handle IO page faults
Date: Wed, 12 Jul 2023 10:45:22 +0100 [thread overview]
Message-ID: <20230712094522.GB507884@myrica> (raw)
In-Reply-To: <cbbe1175-40f3-805e-02c2-f887b3289f04@linux.intel.com>
On Wed, Jul 12, 2023 at 10:32:13AM +0800, Baolu Lu wrote:
> > btw is there value of moving the group handling logic from
> > iommu_queue_iopf() to this common function?
> >
> > I wonder whether there is any correctness issue if not forwarding
> > partial request to iommufd. If not this can also help reduce
> > notifications to the user until the group is ready.
>
> I don't think there's any correctness issue. But it should be better if
> we can inject the page faults to vm guests as soon as possible. There's
> no requirement to put page requests to vIOMMU's hardware page request
> queue at the granularity of a fault group. Thoughts?
Not sure I understand you correctly, but we can't inject partial fault
groups: if the HW PRI queue overflows, the last fault in a group may be
lost, so the non-last faults in that group already injected won't be
completed (until PRGI reuse), leaking PRI request credits and guest
resources.
Thanks,
Jean
next prev parent reply other threads:[~2023-07-12 9:45 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-11 1:06 [PATCH 0/9] iommu: Prepare to deliver page faults to user space Lu Baolu
2023-07-11 1:06 ` [PATCH 1/9] iommu: Move iommu fault data to linux/iommu.h Lu Baolu
2023-07-11 6:05 ` Tian, Kevin
2023-07-12 2:07 ` Baolu Lu
2023-07-12 9:33 ` Jean-Philippe Brucker
2023-07-13 3:22 ` Tian, Kevin
2023-07-13 3:48 ` Baolu Lu
2023-07-11 1:06 ` [PATCH 2/9] iommu: Add device parameter to iopf handler Lu Baolu
2023-07-11 17:26 ` Jacob Pan
2023-07-12 2:16 ` Baolu Lu
2023-07-12 5:46 ` Jacob Pan
2023-07-11 1:06 ` [PATCH 3/9] iommu: Add common code to handle IO page faults Lu Baolu
2023-07-11 6:12 ` Tian, Kevin
2023-07-12 2:32 ` Baolu Lu
2023-07-12 9:45 ` Jean-Philippe Brucker [this message]
2023-07-13 4:02 ` Baolu Lu
2023-07-11 20:50 ` Jacob Pan
2023-07-12 2:37 ` Baolu Lu
2023-07-11 1:06 ` [PATCH 4/9] iommu: Change the return value of dev_iommu_get() Lu Baolu
2023-07-11 21:05 ` Jacob Pan
2023-07-11 1:06 ` [PATCH 5/9] iommu: Make fault_param generic Lu Baolu
2023-07-11 6:14 ` Tian, Kevin
2023-07-12 2:43 ` Baolu Lu
2023-07-11 21:31 ` Jacob Pan
2023-07-12 3:02 ` Baolu Lu
2023-07-11 1:06 ` [PATCH 6/9] iommu: Remove iommu_[un]register_device_fault_handler() Lu Baolu
2023-07-11 1:06 ` [PATCH 7/9] iommu: Add helper to set iopf handler for domain Lu Baolu
2023-07-11 1:06 ` [PATCH 8/9] iommu: Add iommu page fault cookie helpers Lu Baolu
2023-07-11 1:06 ` [PATCH 9/9] iommu: Use fault cookie to store iopf_param Lu Baolu
2023-07-11 6:26 ` Tian, Kevin
2023-07-12 3:09 ` Baolu Lu
2023-07-11 22:02 ` Jacob Pan
2023-07-12 3:13 ` Baolu Lu
2023-07-13 3:24 ` Tian, Kevin
2023-07-13 3:43 ` Baolu Lu
2023-07-13 8:01 ` Tian, Kevin
2023-07-14 2:49 ` Baolu Lu
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