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Message-Id: <20220914011821.400986-1-baolu.lu@linux.intel.com>
Date: Wed, 14 Sep 2022 09:18:21 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: iommu@...ts.linux.dev
Cc: Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Kevin Tian <kevin.tian@...el.com>,
linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v2 1/1] iommu/vt-d: Remove unnecessary SVA data accesses in page fault path
The existing I/O page fault handling code accesses the per-PASID SVA data
structures. This is unnecessary and makes the fault handling code only
suitable for SVA scenarios. This removes the SVA data accesses from the
I/O page fault reporting and responding code, so that the fault handling
code could be generic.
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
drivers/iommu/intel/iommu.h | 2 +-
drivers/iommu/intel/svm.c | 60 +++++--------------------------------
2 files changed, 8 insertions(+), 54 deletions(-)
Change log:
v2:
- Move prq_seq_number to per-iommu data struct.
- Add back the comments that were accidentally deleted.
- Rephrased the commit message.
v1: https://lore.kernel.org/linux-iommu/20220908023557.4582-1-baolu.lu@linux.intel.com/
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 08618d94fbac..352f05e92f6f 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -584,6 +584,7 @@ struct intel_iommu {
#ifdef CONFIG_INTEL_IOMMU_SVM
struct page_req_dsc *prq;
unsigned char prq_name[16]; /* Name for PRQ interrupt */
+ unsigned long prq_seq_number;
struct completion prq_complete;
struct ioasid_allocator_ops pasid_allocator; /* Custom allocator for PASIDs */
#endif
@@ -757,7 +758,6 @@ struct intel_svm_dev {
struct device *dev;
struct intel_iommu *iommu;
struct iommu_sva sva;
- unsigned long prq_seq_number;
u32 pasid;
int users;
u16 did;
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index b391e46e537e..e73b9a202777 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -48,23 +48,6 @@ static void *pasid_private_find(ioasid_t pasid)
return xa_load(&pasid_private_array, pasid);
}
-static struct intel_svm_dev *
-svm_lookup_device_by_sid(struct intel_svm *svm, u16 sid)
-{
- struct intel_svm_dev *sdev = NULL, *t;
-
- rcu_read_lock();
- list_for_each_entry_rcu(t, &svm->devs, list) {
- if (t->sid == sid) {
- sdev = t;
- break;
- }
- }
- rcu_read_unlock();
-
- return sdev;
-}
-
static struct intel_svm_dev *
svm_lookup_device_by_dev(struct intel_svm *svm, struct device *dev)
{
@@ -689,11 +672,10 @@ static void handle_bad_prq_event(struct intel_iommu *iommu,
static irqreturn_t prq_event_thread(int irq, void *d)
{
- struct intel_svm_dev *sdev = NULL;
struct intel_iommu *iommu = d;
- struct intel_svm *svm = NULL;
struct page_req_dsc *req;
int head, tail, handled;
+ struct pci_dev *pdev;
u64 address;
/*
@@ -713,8 +695,6 @@ static irqreturn_t prq_event_thread(int irq, void *d)
pr_err("IOMMU: %s: Page request without PASID\n",
iommu->name);
bad_req:
- svm = NULL;
- sdev = NULL;
handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
goto prq_advance;
}
@@ -741,34 +721,19 @@ static irqreturn_t prq_event_thread(int irq, void *d)
if (unlikely(req->lpig && !req->rd_req && !req->wr_req))
goto prq_advance;
- if (!svm || svm->pasid != req->pasid) {
- /*
- * It can't go away, because the driver is not permitted
- * to unbind the mm while any page faults are outstanding.
- */
- svm = pasid_private_find(req->pasid);
- if (IS_ERR_OR_NULL(svm))
- goto bad_req;
- }
-
- if (!sdev || sdev->sid != req->rid) {
- sdev = svm_lookup_device_by_sid(svm, req->rid);
- if (!sdev)
- goto bad_req;
- }
-
- sdev->prq_seq_number++;
-
+ pdev = pci_get_domain_bus_and_slot(iommu->segment,
+ PCI_BUS_NUM(req->rid),
+ req->rid & 0xff);
/*
* If prq is to be handled outside iommu driver via receiver of
* the fault notifiers, we skip the page response here.
*/
- if (intel_svm_prq_report(iommu, sdev->dev, req))
+ if (!pdev || intel_svm_prq_report(iommu, &pdev->dev, req))
handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
- trace_prq_report(iommu, sdev->dev, req->qw_0, req->qw_1,
+ trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
req->priv_data[0], req->priv_data[1],
- sdev->prq_seq_number);
+ iommu->prq_seq_number++);
prq_advance:
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}
@@ -803,8 +768,6 @@ int intel_svm_page_response(struct device *dev,
struct iommu_page_response *msg)
{
struct iommu_fault_page_request *prm;
- struct intel_svm_dev *sdev = NULL;
- struct intel_svm *svm = NULL;
struct intel_iommu *iommu;
bool private_present;
bool pasid_present;
@@ -823,8 +786,6 @@ int intel_svm_page_response(struct device *dev,
if (!msg || !evt)
return -EINVAL;
- mutex_lock(&pasid_mutex);
-
prm = &evt->fault.prm;
sid = PCI_DEVID(bus, devfn);
pasid_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
@@ -841,12 +802,6 @@ int intel_svm_page_response(struct device *dev,
goto out;
}
- ret = pasid_to_svm_sdev(dev, prm->pasid, &svm, &sdev);
- if (ret || !sdev) {
- ret = -ENODEV;
- goto out;
- }
-
/*
* Per VT-d spec. v3.0 ch7.7, system software must respond
* with page group response if private data is present (PDP)
@@ -876,7 +831,6 @@ int intel_svm_page_response(struct device *dev,
qi_submit_sync(iommu, &desc, 1, 0);
}
out:
- mutex_unlock(&pasid_mutex);
return ret;
}
--
2.34.1
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