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Message-ID: <20170622165416.6ea718f1@w520.home>
Date: Thu, 22 Jun 2017 16:54:16 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: iommu@...ts.linux-foundation.org,
LKML <linux-kernel@...r.kernel.org>,
Joerg Roedel <joro@...tes.org>,
David Woodhouse <dwmw2@...radead.org>,
"Liu, Yi L" <yi.l.liu@...el.com>,
Lan Tianyu <tianyu.lan@...el.com>,
"Tian, Kevin" <kevin.tian@...el.com>,
Raj Ashok <ashok.raj@...el.com>,
Jean Delvare <khali@...ux-fr.org>
Subject: Re: [RFC 7/9] iommu/dmar: notify unrecoverable faults
On Wed, 14 Jun 2017 15:23:01 -0700
Jacob Pan <jacob.jun.pan@...ux.intel.com> wrote:
> Currently, when device DMA faults are detected by IOMMU the fault
> reasons are printed but the offending device is not notified.
> This patch allows device drivers to be optionally notified for fault
> conditions when device specific handling is needed for more subtle
> processing, e.g. request with PASID transactions.
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> Signed-off-by: Ashok Raj <ashok.raj@...el.com>
> ---
> drivers/iommu/dmar.c | 37 ++++++++++++++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index cbf7763..2c0b80d464 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -1587,11 +1587,43 @@ void dmar_msi_read(int irq, struct msi_msg *msg)
> raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
> }
>
> +static int dmar_unrecov_fault_notify(u8 fault_reason, u16 source_id,
> + unsigned long long addr)
> +{
> + int ret;
> + struct pci_dev *pdev;
> + struct iommu_fault_event *event;
> +
> + pdev = pci_get_bus_and_slot(source_id >> 8, source_id & 0xFF);
> + if (!pdev)
> + return -ENODEV;
> + pr_debug("Notify PCI device fault [%02x:%02x.%d]\n",
> + source_id >> 8, PCI_SLOT(source_id & 0xff),
> + PCI_FUNC(source_id & 0xff));
> + event = kzalloc(sizeof(*event) + sizeof(fault_reason), GFP_KERNEL);
> + if (!event)
> + return -ENOMEM;
Leaks pdev reference.
> +
> + pci_dev_get(pdev);
> + event->dev = &pdev->dev;
> + event->buf[0] = fault_reason;
> + event->addr = addr;
> + event->length = sizeof(fault_reason);
> + event->flags = IOMMU_FAULT_UNRECOV;
> + ret = iommu_fault_notifier_call_chain(event);
> +
> + pci_dev_put(pdev);
> + kfree(event);
> +
> + return ret;
> +}
> +
> static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
> u8 fault_reason, u16 source_id, unsigned long long addr)
> {
> const char *reason;
> int fault_type;
> + int ret = 0;
>
> reason = dmar_get_fault_reason(fault_reason, &fault_type);
>
> @@ -1600,11 +1632,14 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
> source_id >> 8, PCI_SLOT(source_id & 0xFF),
> PCI_FUNC(source_id & 0xFF), addr >> 48,
> fault_reason, reason);
> - else
> + else {
> pr_err("[%s] Request device [%02x:%02x.%d] fault addr %llx [fault reason %02d] %s\n",
> type ? "DMA Read" : "DMA Write",
> source_id >> 8, PCI_SLOT(source_id & 0xFF),
> PCI_FUNC(source_id & 0xFF), addr, fault_reason, reason);
> + ret = dmar_unrecov_fault_notify(fault_reason, source_id, addr);
For what purpose are we recording this return code?
> + }
> +
> return 0;
> }
>
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