From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>,
iommu@lists.linux-foundation.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
linux-mm@kvack.org
Cc: fenghua.yu@intel.com, kevin.tian@intel.com, jgg@ziepe.ca,
catalin.marinas@arm.com, robin.murphy@arm.com, hch@infradead.org,
zhangfei.gao@linaro.org, felix.kuehling@amd.com, will@kernel.org,
christian.koenig@amd.com
Subject: Re: [PATCH v6 05/25] iommu/iopf: Handle mm faults
Date: Sun, 3 May 2020 13:54:36 +0800 [thread overview]
Message-ID: <9fc0e4cc-1242-bf96-5328-cc9039dcc9b6@linux.intel.com> (raw)
In-Reply-To: <20200430143424.2787566-6-jean-philippe@linaro.org>
On 2020/4/30 22:34, Jean-Philippe Brucker wrote:
> When a recoverable page fault is handled by the fault workqueue, find the
> associated mm and call handle_mm_fault.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> v5->v6: select CONFIG_IOMMU_SVA
> ---
> drivers/iommu/Kconfig | 1 +
> drivers/iommu/io-pgfault.c | 79 +++++++++++++++++++++++++++++++++++++-
> 2 files changed, 78 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 4f33e489f0726..1e64ee6592e16 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -109,6 +109,7 @@ config IOMMU_SVA
>
> config IOMMU_PAGE_FAULT
> bool
> + select IOMMU_SVA
It would be better to move this to the previous patch.
>
> config FSL_PAMU
> bool "Freescale IOMMU support"
> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
> index 38732e97faac1..09a71dc4de20a 100644
> --- a/drivers/iommu/io-pgfault.c
> +++ b/drivers/iommu/io-pgfault.c
> @@ -7,9 +7,12 @@
>
> #include <linux/iommu.h>
> #include <linux/list.h>
> +#include <linux/sched/mm.h>
> #include <linux/slab.h>
> #include <linux/workqueue.h>
>
> +#include "iommu-sva.h"
> +
> /**
> * struct iopf_queue - IO Page Fault queue
> * @wq: the fault workqueue
> @@ -68,8 +71,57 @@ static int iopf_complete_group(struct device *dev, struct iopf_fault *iopf,
> static enum iommu_page_response_code
> iopf_handle_single(struct iopf_fault *iopf)
> {
> - /* TODO */
> - return -ENODEV;
> + vm_fault_t ret;
> + struct mm_struct *mm;
> + struct vm_area_struct *vma;
> + unsigned int access_flags = 0;
> + unsigned int fault_flags = FAULT_FLAG_REMOTE;
> + struct iommu_fault_page_request *prm = &iopf->fault.prm;
> + enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
> +
> + if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
> + return status;
> +
> + mm = iommu_sva_find(prm->pasid);
> + if (IS_ERR_OR_NULL(mm))
> + return status;
> +
> + down_read(&mm->mmap_sem);
> +
> + vma = find_extend_vma(mm, prm->addr);
> + if (!vma)
> + /* Unmapped area */
> + goto out_put_mm;
> +
> + if (prm->perm & IOMMU_FAULT_PERM_READ)
> + access_flags |= VM_READ;
> +
> + if (prm->perm & IOMMU_FAULT_PERM_WRITE) {
> + access_flags |= VM_WRITE;
> + fault_flags |= FAULT_FLAG_WRITE;
> + }
> +
> + if (prm->perm & IOMMU_FAULT_PERM_EXEC) {
> + access_flags |= VM_EXEC;
> + fault_flags |= FAULT_FLAG_INSTRUCTION;
> + }
> +
> + if (!(prm->perm & IOMMU_FAULT_PERM_PRIV))
> + fault_flags |= FAULT_FLAG_USER;
> +
> + if (access_flags & ~vma->vm_flags)
> + /* Access fault */
> + goto out_put_mm;
> +
> + ret = handle_mm_fault(vma, prm->addr, fault_flags);
> + status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID :
> + IOMMU_PAGE_RESP_SUCCESS;
> +
> +out_put_mm:
> + up_read(&mm->mmap_sem);
> + mmput(mm);
> +
> + return status;
> }
>
> static void iopf_handle_group(struct work_struct *work)
> @@ -104,6 +156,29 @@ static void iopf_handle_group(struct work_struct *work)
> *
> * Add a fault to the device workqueue, to be handled by mm.
> *
> + * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard
> + * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't
> + * expect a response. It may be generated when disabling a PASID (issuing a
> + * PASID stop request) by some PCI devices.
> + *
> + * The PASID stop request is issued by the device driver before unbind(). Once
> + * it completes, no page request is generated for this PASID anymore and
> + * outstanding ones have been pushed to the IOMMU (as per PCIe 4.0r1.0 - 6.20.1
> + * and 10.4.1.2 - Managing PASID TLP Prefix Usage). Some PCI devices will wait
> + * for all outstanding page requests to come back with a response before
> + * completing the PASID stop request. Others do not wait for page responses, and
> + * instead issue this Stop Marker that tells us when the PASID can be
> + * reallocated.
> + *
> + * It is safe to discard the Stop Marker because it is an optimization.
> + * a. Page requests, which are posted requests, have been flushed to the IOMMU
> + * when the stop request completes.
> + * b. We flush all fault queues on unbind() before freeing the PASID.
> + *
> + * So even though the Stop Marker might be issued by the device *after* the stop
> + * request completes, outstanding faults will have been dealt with by the time
> + * we free the PASID.
> + *
> * Return: 0 on success and <0 on error.
> */
> int iommu_queue_iopf(struct iommu_fault *fault, void *cookie)
>
The same for the comments.
Best regards,
baolu
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next prev parent reply other threads:[~2020-05-03 5:54 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 14:33 [PATCH v6 00/25] iommu: Shared Virtual Addressing for SMMUv3 Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 01/25] mm: Add a PASID field to mm_struct Jean-Philippe Brucker
2020-05-04 1:52 ` Xu Zaibo
2020-05-04 16:29 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 02/25] iommu/ioasid: Add ioasid references Jean-Philippe Brucker
2020-04-30 18:39 ` Jacob Pan
2020-04-30 20:48 ` Jacob Pan
2020-05-04 14:39 ` Jean-Philippe Brucker
2020-05-04 15:22 ` Jacob Pan
2020-05-04 14:25 ` Jean-Philippe Brucker
2020-05-04 15:27 ` Jacob Pan
2020-04-30 14:34 ` [PATCH v6 03/25] iommu/sva: Add PASID helpers Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 04/25] iommu: Add a page fault handler Jean-Philippe Brucker
2020-05-03 5:49 ` Lu Baolu
2020-05-04 16:22 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 05/25] iommu/iopf: Handle mm faults Jean-Philippe Brucker
2020-05-03 5:54 ` Lu Baolu [this message]
2020-05-04 16:25 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 06/25] arm64: mm: Add asid_gen_match() helper Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 07/25] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 08/25] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 09/25] iommu/arm-smmu-v3: Manage ASIDs with xarray Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 10/25] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-04-30 15:18 ` Suzuki K Poulose
2020-04-30 14:34 ` [PATCH v6 11/25] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-04-30 15:39 ` Suzuki K Poulose
2020-05-04 14:11 ` Jean-Philippe Brucker
2020-05-04 14:42 ` Suzuki K Poulose
2020-04-30 14:34 ` [PATCH v6 12/25] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 13/25] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 14/25] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 15/25] iommu/arm-smmu-v3: Add SVA feature checking Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 16/25] iommu/arm-smmu-v3: Add SVA device feature Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 17/25] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Jean-Philippe Brucker
2020-04-30 21:16 ` Jacob Pan
2020-05-04 16:43 ` Jean-Philippe Brucker
2020-05-04 20:47 ` Jacob Pan
2020-05-05 9:15 ` Jean-Philippe Brucker
2020-05-07 16:31 ` Jacob Pan
2020-05-01 12:15 ` Christoph Hellwig
2020-05-01 12:55 ` Jason Gunthorpe
2020-05-04 16:07 ` Jean-Philippe Brucker
2020-05-04 16:06 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 18/25] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 19/25] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Jean-Philippe Brucker
2020-05-04 14:24 ` Prabhakar Kushwaha
2020-05-04 16:35 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 20/25] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 21/25] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 22/25] iommu/arm-smmu-v3: Add stall support for platform devices Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 23/25] PCI/ATS: Add PRI stubs Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 24/25] PCI/ATS: Export PRI functions Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 25/25] iommu/arm-smmu-v3: Add support for PRI Jean-Philippe Brucker
2020-04-30 21:18 ` [PATCH v6 00/25] iommu: Shared Virtual Addressing for SMMUv3 Jacob Pan
2020-05-04 15:09 ` Jean-Philippe Brucker
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