From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: 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: joro@8bytes.org, robh+dt@kernel.org, mark.rutland@arm.com,
catalin.marinas@arm.com, will@kernel.org, robin.murphy@arm.com,
kevin.tian@intel.com, baolu.lu@linux.intel.com,
Jonathan.Cameron@huawei.com, jacob.jun.pan@linux.intel.com,
christian.koenig@amd.com, yi.l.liu@intel.com,
zhangfei.gao@linaro.org,
Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Subject: [PATCH v4 05/26] iommu/iopf: Handle mm faults
Date: Mon, 24 Feb 2020 19:23:40 +0100 [thread overview]
Message-ID: <20200224182401.353359-6-jean-philippe@linaro.org> (raw)
In-Reply-To: <20200224182401.353359-1-jean-philippe@linaro.org>
From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
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>
---
drivers/iommu/io-pgfault.c | 86 +++++++++++++++++++++++++++++++++++++-
1 file changed, 84 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index 76e153c59fe3..ffa9f14e0803 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -7,6 +7,7 @@
#include <linux/iommu.h>
#include <linux/list.h>
+#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
@@ -76,8 +77,65 @@ static int iopf_complete(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);
+
+ /*
+ * If the process exits while we're handling the fault on its mm, we
+ * can't do mmput(). exit_mmap() would release the MMU notifier, calling
+ * iommu_notifier_release(), which has to flush the fault queue that
+ * we're executing on... So mmput_async() moves the release of the mm to
+ * another thread, if we're the last user.
+ */
+ mmput_async(mm);
+
+ return status;
}
static void iopf_handle_group(struct work_struct *work)
@@ -111,6 +169,30 @@ 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 triggered by the mm_exit() callback. When the
+ * callback returns from the device driver, 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 mm_exit() returns,
+ * b. We flush all fault queues after mm_exit() returns and 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)
--
2.25.0
next prev parent reply other threads:[~2020-02-24 18:24 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 18:23 [PATCH v4 00/26] iommu: Shared Virtual Addressing and SMMUv3 support Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 01/26] mm/mmu_notifiers: pass private data down to alloc_notifier() Jean-Philippe Brucker
2020-02-24 19:00 ` Jason Gunthorpe
2020-02-25 9:24 ` Jean-Philippe Brucker
2020-02-25 14:08 ` Jason Gunthorpe
2020-02-28 14:39 ` Jean-Philippe Brucker
2020-02-28 14:48 ` Jason Gunthorpe
2020-02-28 15:04 ` Jean-Philippe Brucker
2020-02-28 15:13 ` Jason Gunthorpe
2020-03-06 9:56 ` Jean-Philippe Brucker
2020-03-06 13:09 ` Jason Gunthorpe
2020-03-06 14:35 ` Jean-Philippe Brucker
2020-03-06 14:52 ` Jason Gunthorpe
2020-03-06 16:15 ` Jean-Philippe Brucker
2020-03-06 17:42 ` Jason Gunthorpe
2020-03-13 18:49 ` Jean-Philippe Brucker
2020-03-13 19:13 ` Jason Gunthorpe
2020-03-16 15:46 ` Christoph Hellwig
2020-03-17 18:40 ` Jason Gunthorpe
2020-03-05 16:36 ` Christoph Hellwig
2020-02-24 18:23 ` [PATCH v4 02/26] iommu/sva: Manage process address spaces Jean-Philippe Brucker
2020-02-26 12:35 ` Jonathan Cameron
2020-02-28 14:43 ` Jean-Philippe Brucker
2020-02-28 16:26 ` Jonathan Cameron
2020-02-26 19:13 ` Jacob Pan
2020-02-28 14:40 ` Jean-Philippe Brucker
2020-02-28 14:57 ` Jason Gunthorpe
2020-02-24 18:23 ` [PATCH v4 03/26] iommu: Add a page fault handler Jean-Philippe Brucker
2020-02-25 3:30 ` Xu Zaibo
2020-02-25 9:25 ` Jean-Philippe Brucker
2020-02-26 3:05 ` Xu Zaibo
2020-02-26 13:59 ` Jonathan Cameron
2020-02-28 14:44 ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 04/26] iommu/sva: Search mm by PASID Jean-Philippe Brucker
2020-02-24 18:23 ` Jean-Philippe Brucker [this message]
2020-02-24 18:23 ` [PATCH v4 06/26] iommu/sva: Register page fault handler Jean-Philippe Brucker
2020-02-26 19:39 ` Jacob Pan
2020-02-28 14:44 ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 07/26] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-02-27 17:43 ` Jonathan Cameron
2020-03-04 14:10 ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 08/26] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 09/26] iommu/arm-smmu-v3: Manage ASIDs with xarray Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 10/26] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 11/26] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 12/26] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 13/26] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 14/26] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 15/26] iommu/arm-smmu-v3: Add SVA feature checking Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 16/26] iommu/arm-smmu-v3: Add dev_to_master() helper Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 17/26] iommu/arm-smmu-v3: Implement mm operations Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 18/26] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 19/26] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 20/26] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 21/26] iommu/arm-smmu-v3: Ratelimit event dump Jean-Philippe Brucker
2021-05-28 8:09 ` Aaro Koskinen
2021-05-28 16:25 ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 22/26] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 23/26] iommu/arm-smmu-v3: Add stall support for platform devices Jean-Philippe Brucker
2020-02-26 8:44 ` Xu Zaibo
2020-03-04 14:09 ` Jean-Philippe Brucker
2020-02-27 18:17 ` Jonathan Cameron
2020-03-04 14:08 ` Jean-Philippe Brucker
2020-03-09 10:48 ` Jonathan Cameron
2020-02-24 18:23 ` [PATCH v4 24/26] PCI/ATS: Add PRI stubs Jean-Philippe Brucker
2020-02-27 20:55 ` Bjorn Helgaas
2020-02-24 18:24 ` [PATCH v4 25/26] PCI/ATS: Export symbols of PRI functions Jean-Philippe Brucker
2020-02-27 20:55 ` Bjorn Helgaas
2020-02-24 18:24 ` [PATCH v4 26/26] iommu/arm-smmu-v3: Add support for PRI Jean-Philippe Brucker
2020-02-27 18:22 ` [PATCH v4 00/26] iommu: Shared Virtual Addressing and SMMUv3 support Jonathan Cameron
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