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Message-ID: <32475465-caef-4202-80f4-410a173e400e@linux.intel.com>
Date: Thu, 29 Feb 2024 12:08:57 +0800
From: Ethan Zhao <haifeng.zhao@...ux.intel.com>
To: baolu.lu@...ux.intel.com, bhelgaas@...gle.com, robin.murphy@....com,
jgg@...pe.ca
Cc: kevin.tian@...el.com, dwmw2@...radead.org, will@...nel.org,
lukas@...ner.de, yi.l.liu@...el.com, dan.carpenter@...aro.org,
iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iommu/vt-d: improve ITE fault handling if device was
released
On 2/29/2024 12:07 PM, Ethan Zhao wrote:
> Break the loop to blindly retry the timeout ATS invalidation request
> after ITE fault hit if device was released or isn't present anymore.
>
> This is part of the followup of prior proposed patchset
>
> https://do-db2.lkml.org/lkml/2024/2/22/350
>
> Fixes: 6ba6c3a4cacf ("VT-d: add device IOTLB invalidation support")
> Signed-off-by: Ethan Zhao <haifeng.zhao@...ux.intel.com>
> ---
> drivers/iommu/intel/dmar.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
> index d14797aabb7a..d01d68205557 100644
> --- a/drivers/iommu/intel/dmar.c
> +++ b/drivers/iommu/intel/dmar.c
> @@ -1273,6 +1273,9 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index)
> {
> u32 fault;
> int head, tail;
> + u64 iqe_err, ite_sid;
> + struct device *dev = NULL;
> + struct pci_dev *pdev = NULL;
> struct q_inval *qi = iommu->qi;
> int shift = qi_shift(iommu);
>
> @@ -1317,6 +1320,13 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index)
> tail = readl(iommu->reg + DMAR_IQT_REG);
> tail = ((tail >> shift) - 1 + QI_LENGTH) % QI_LENGTH;
>
> + /*
> + * SID field is valid only when the ITE field is Set in FSTS_REG
> + * see Intel VT-d spec r4.1, section 11.4.9.9
> + */
> + iqe_err = dmar_readq(iommu->reg + DMAR_IQER_REG);
> + ite_sid = DMAR_IQER_REG_ITESID(iqe_err);
> +
> writel(DMA_FSTS_ITE, iommu->reg + DMAR_FSTS_REG);
> pr_info("Invalidation Time-out Error (ITE) cleared\n");
>
> @@ -1326,6 +1336,21 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index)
> head = (head - 2 + QI_LENGTH) % QI_LENGTH;
> } while (head != tail);
>
> + /*
> + * If got ITE, we need to check if the sid of ITE is one of the
> + * current valid ATS invalidation target devices, if no, or the
> + * target device isn't presnet, don't try this request anymore.
> + * 0 value of ite_sid means old VT-d device, no ite_sid value.
> + */
> + if (ite_sid) {
> + dev = device_rbtree_find(iommu, ite_sid);
> + if (!dev || !dev_is_pci(dev))
> + return -ETIMEDOUT;
> + pdev = to_pci_dev(dev);
> + if (!pci_device_is_present(pdev) &&
> + ite_sid == pci_dev_id(pci_physfn(pdev)))
> + return -ETIMEDOUT;
> + }
> if (qi->desc_status[wait_index] == QI_ABORT)
> return -EAGAIN;
> }
This patch based on Baolu's per iommu device rbtree patchset
https://github.com/LuBaolu/intel-iommu/commits/rbtree-for-device-info-v2
Thanks,
Ethan
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