[PATCH v5 1/5] iommu/vt-d: Multiple descriptors per qi_submit_sync()

From: Lu Baolu
Date: Mon May 11 2020 - 20:56:39 EST

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Current qi_submit_sync() only supports single invalidation descriptor
per submission and appends wait descriptor after each submission to
poll the hardware completion. This extends the qi_submit_sync() helper
to support multiple descriptors, and add an option so that the caller
could specify the Page-request Drain (PD) bit in the wait descriptor.

Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
drivers/iommu/dmar.c | 63 +++++++++++++++++------------
drivers/iommu/intel-pasid.c | 4 +-
drivers/iommu/intel-svm.c | 6 +--
drivers/iommu/intel_irq_remapping.c | 2 +-
include/linux/intel-iommu.h | 9 ++++-
5 files changed, 52 insertions(+), 32 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index d9dc787feef7..61d049e91f84 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1157,12 +1157,11 @@ static inline void reclaim_free_desc(struct q_inval *qi)
}
}

-static int qi_check_fault(struct intel_iommu *iommu, int index)
+static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index)
{
u32 fault;
int head, tail;
struct q_inval *qi = iommu->qi;
- int wait_index = (index + 1) % QI_LENGTH;
int shift = qi_shift(iommu);

if (qi->desc_status[wait_index] == QI_ABORT)
@@ -1225,17 +1224,21 @@ static int qi_check_fault(struct intel_iommu *iommu, int index)
}

/*
- * Submit the queued invalidation descriptor to the remapping
- * hardware unit and wait for its completion.
+ * Function to submit invalidation descriptors of all types to the queued
+ * invalidation interface(QI). Multiple descriptors can be submitted at a
+ * time, a wait descriptor will be appended to each submission to ensure
+ * hardware has completed the invalidation before return. Wait descriptors
+ * can be part of the submission but it will not be polled for completion.
*/
-int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
+int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
+ unsigned int count, unsigned long options)
{
- int rc;
struct q_inval *qi = iommu->qi;
- int offset, shift, length;
struct qi_desc wait_desc;
int wait_index, index;
unsigned long flags;
+ int offset, shift;
+ int rc, i;

if (!qi)
return 0;
@@ -1244,32 +1247,41 @@ int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
rc = 0;

raw_spin_lock_irqsave(&qi->q_lock, flags);
- while (qi->free_cnt < 3) {
+ /*
+ * Check if we have enough empty slots in the queue to submit,
+ * the calculation is based on:
+ * # of desc + 1 wait desc + 1 space between head and tail
+ */
+ while (qi->free_cnt < count + 2) {
raw_spin_unlock_irqrestore(&qi->q_lock, flags);
cpu_relax();
raw_spin_lock_irqsave(&qi->q_lock, flags);
}

index = qi->free_head;
- wait_index = (index + 1) % QI_LENGTH;
+ wait_index = (index + count) % QI_LENGTH;
shift = qi_shift(iommu);
- length = 1 << shift;

- qi->desc_status[index] = qi->desc_status[wait_index] = QI_IN_USE;
+ for (i = 0; i < count; i++) {
+ offset = ((index + i) % QI_LENGTH) << shift;
+ memcpy(qi->desc + offset, &desc[i], 1 << shift);
+ qi->desc_status[(index + i) % QI_LENGTH] = QI_IN_USE;
+ }
+ qi->desc_status[wait_index] = QI_IN_USE;

- offset = index << shift;
- memcpy(qi->desc + offset, desc, length);
wait_desc.qw0 = QI_IWD_STATUS_DATA(QI_DONE) |
QI_IWD_STATUS_WRITE | QI_IWD_TYPE;
+ if (options & QI_OPT_WAIT_DRAIN)
+ wait_desc.qw0 |= QI_IWD_PRQ_DRAIN;
wait_desc.qw1 = virt_to_phys(&qi->desc_status[wait_index]);
wait_desc.qw2 = 0;
wait_desc.qw3 = 0;

offset = wait_index << shift;
- memcpy(qi->desc + offset, &wait_desc, length);
+ memcpy(qi->desc + offset, &wait_desc, 1 << shift);

- qi->free_head = (qi->free_head + 2) % QI_LENGTH;
- qi->free_cnt -= 2;
+ qi->free_head = (qi->free_head + count + 1) % QI_LENGTH;
+ qi->free_cnt -= count + 1;

/*
* update the HW tail register indicating the presence of
@@ -1285,7 +1297,7 @@ int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
* a deadlock where the interrupt context can wait indefinitely
* for free slots in the queue.
*/
- rc = qi_check_fault(iommu, index);
+ rc = qi_check_fault(iommu, index, wait_index);
if (rc)
break;

@@ -1294,7 +1306,8 @@ int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu)
raw_spin_lock(&qi->q_lock);
}

- qi->desc_status[index] = QI_DONE;
+ for (i = 0; i < count; i++)
+ qi->desc_status[(index + i) % QI_LENGTH] = QI_DONE;

reclaim_free_desc(qi);
raw_spin_unlock_irqrestore(&qi->q_lock, flags);
@@ -1318,7 +1331,7 @@ void qi_global_iec(struct intel_iommu *iommu)
desc.qw3 = 0;

/* should never fail */
- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid, u8 fm,
@@ -1332,7 +1345,7 @@ void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid, u8 fm,
desc.qw2 = 0;
desc.qw3 = 0;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
@@ -1356,7 +1369,7 @@ void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
desc.qw2 = 0;
desc.qw3 = 0;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
@@ -1378,7 +1391,7 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
desc.qw2 = 0;
desc.qw3 = 0;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

/* PASID-based IOTLB invalidation */
@@ -1419,7 +1432,7 @@ void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u32 pasid, u64 addr,
QI_EIOTLB_AM(mask);
}

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

/* PASID-based device IOTLB Invalidate */
@@ -1448,7 +1461,7 @@ void qi_flush_dev_iotlb_pasid(struct intel_iommu *iommu, u16 sid, u16 pfsid,
if (size_order)
desc.qw1 |= QI_DEV_EIOTLB_SIZE;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did,
@@ -1458,7 +1471,7 @@ void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did,

desc.qw0 = QI_PC_PASID(pasid) | QI_PC_DID(did) |
QI_PC_GRAN(granu) | QI_PC_TYPE;
- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

/*
diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index 48cc9ca5f3dc..7969e3dac2ad 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -498,7 +498,7 @@ pasid_cache_invalidation_with_pasid(struct intel_iommu *iommu,
desc.qw2 = 0;
desc.qw3 = 0;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

static void
@@ -512,7 +512,7 @@ iotlb_invalidation_with_pasid(struct intel_iommu *iommu, u16 did, u32 pasid)
desc.qw2 = 0;
desc.qw3 = 0;

- qi_submit_sync(&desc, iommu);
+ qi_submit_sync(iommu, &desc, 1, 0);
}

static void
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index e9f4e979a71f..83dc4319f661 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -138,7 +138,7 @@ static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_d
}
desc.qw2 = 0;
desc.qw3 = 0;
- qi_submit_sync(&desc, svm->iommu);
+ qi_submit_sync(svm->iommu, &desc, 1, 0);

if (sdev->dev_iotlb) {
desc.qw0 = QI_DEV_EIOTLB_PASID(svm->pasid) |
@@ -162,7 +162,7 @@ static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_d
}
desc.qw2 = 0;
desc.qw3 = 0;
- qi_submit_sync(&desc, svm->iommu);
+ qi_submit_sync(svm->iommu, &desc, 1, 0);
}
}

@@ -850,7 +850,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
sizeof(req->priv_data));
resp.qw2 = 0;
resp.qw3 = 0;
- qi_submit_sync(&resp, iommu);
+ qi_submit_sync(iommu, &resp, 1, 0);
}
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 81e43c1df7ec..a042f123b091 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -151,7 +151,7 @@ static int qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
desc.qw2 = 0;
desc.qw3 = 0;

- return qi_submit_sync(&desc, iommu);
+ return qi_submit_sync(iommu, &desc, 1, 0);
}

static int modify_irte(struct irq_2_iommu *irq_iommu,
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index cfe720f10112..cca1e5f9aeaa 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -333,6 +333,7 @@ enum {

#define QI_IWD_STATUS_DATA(d) (((u64)d) << 32)
#define QI_IWD_STATUS_WRITE (((u64)1) << 5)
+#define QI_IWD_PRQ_DRAIN (((u64)1) << 7)

#define QI_IOTLB_DID(did) (((u64)did) << 16)
#define QI_IOTLB_DR(dr) (((u64)dr) << 7)
@@ -710,7 +711,13 @@ void qi_flush_dev_iotlb_pasid(struct intel_iommu *iommu, u16 sid, u16 pfsid,
void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64 granu,
int pasid);

-extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
+int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
+ unsigned int count, unsigned long options);
+/*
+ * Options used in qi_submit_sync:
+ * QI_OPT_WAIT_DRAIN - Wait for PRQ drain completion, spec 6.5.2.8.
+ */
+#define QI_OPT_WAIT_DRAIN BIT(0)

extern int dmar_ir_support(void);

--
2.17.1

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