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From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>
Subject: Re: [PATCH v2 3/4] iommu/vt-d: Report page request faults for guest SVA
Date: Tue, 7 Jul 2020 13:23:44 +0200	[thread overview]
Message-ID: <20200707112344.GB159413@myrica> (raw)
In-Reply-To: <20200706002535.9381-4-baolu.lu@linux.intel.com>

On Mon, Jul 06, 2020 at 08:25:34AM +0800, Lu Baolu wrote:
> A pasid might be bound to a page table from a VM guest via the iommu
> ops.sva_bind_gpasid. In this case, when a DMA page fault is detected
> on the physical IOMMU, we need to inject the page fault request into
> the guest. After the guest completes handling the page fault, a page
> response need to be sent back via the iommu ops.page_response().
> 
> This adds support to report a page request fault. Any external module
> which is interested in handling this fault should regiester a notifier
> callback.
> 
> Co-developed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Co-developed-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
[...]
> +static int
> +intel_svm_prq_report(struct device *dev, struct page_req_dsc *desc)
> +{
> +	struct iommu_fault_event event;
> +	u8 bus, devfn;
> +
> +	memset(&event, 0, sizeof(struct iommu_fault_event));
> +	bus = PCI_BUS_NUM(desc->rid);
> +	devfn = desc->rid & 0xff;
> +
> +	/* Fill in event data for device specific processing */
> +	event.fault.type = IOMMU_FAULT_PAGE_REQ;
> +	event.fault.prm.addr = desc->addr;
> +	event.fault.prm.pasid = desc->pasid;
> +	event.fault.prm.grpid = desc->prg_index;
> +	event.fault.prm.perm = prq_to_iommu_prot(desc);
> +
> +	/*
> +	 * Set last page in group bit if private data is present,
> +	 * page response is required as it does for LPIG.
> +	 */
> +	if (desc->lpig)
> +		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
> +	if (desc->pasid_present)
> +		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;

Do you also need to set IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID?  I added
the flag to deal with devices that do not want a PASID value in their PRI
response (bit 15 in the PCIe Page Request Status Register):
https://lore.kernel.org/linux-iommu/20200616144712.748818-1-jean-philippe@linaro.org/
(applied by Joerg for v5.9)

Grepping for pci_prg_resp_pasid_required() in intel/iommu.c it seems to
currently reject devices that do not want a PASID in a PRI response, so I
think you can set this flag unconditionally for now.

Thanks,
Jean

> +	if (desc->priv_data_present) {
> +		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
> +		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
> +		memcpy(event.fault.prm.private_data, desc->priv_data,
> +		       sizeof(desc->priv_data));
> +	}
> +
> +	return iommu_report_device_fault(dev, &event);
> +}
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  parent reply	other threads:[~2020-07-07 11:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-06  0:25 [PATCH v2 0/4] iommu/vt-d: Add prq report and response support Lu Baolu
2020-07-06  0:25 ` [PATCH v2 1/4] iommu/vt-d: Refactor device_to_iommu() helper Lu Baolu
2020-07-06  1:02   ` Tian, Kevin
2020-07-06  0:25 ` [PATCH v2 2/4] iommu/vt-d: Add a helper to get svm and sdev for pasid Lu Baolu
2020-07-06  1:10   ` Tian, Kevin
2020-07-06  0:25 ` [PATCH v2 3/4] iommu/vt-d: Report page request faults for guest SVA Lu Baolu
2020-07-06  1:29   ` Tian, Kevin
2020-07-06  7:37     ` Lu Baolu
2020-07-06  1:36   ` Tian, Kevin
2020-07-06  7:47     ` Lu Baolu
2020-07-07 11:23   ` Jean-Philippe Brucker [this message]
2020-07-08  2:13     ` Lu Baolu
2020-07-06  0:25 ` [PATCH v2 4/4] iommu/vt-d: Add page response ops support Lu Baolu
2020-07-06  1:47   ` Tian, Kevin
2020-07-09  0:32     ` Lu Baolu

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