Re: [PATCH v2 8/8] dmaengine/idxd: Re-enable kernel workqueue under DMA API
From: Fenghua Yu
Date: Tue Mar 28 2023 - 14:16:51 EST
Hi, Jacob,
On 3/27/23 16:21, Jacob Pan wrote:
Kernel workqueues were disabled due to flawed use of kernel VA and SVA
API. Now That we have the support for attaching PASID to the device's
s/That/that/
default domain and the ability to reserve global PASIDs from SVA APIs,
we can re-enable the kernel work queues and use them under DMA API.
We also use non-privileged access for in-kernel DMA to be consistent
with the IOMMU settings. Consequently, interrupt for user privilege is
enabled for work completion IRQs.
Link:https://lore.kernel.org/linux-iommu/20210511194726.GP1002214@xxxxxxxxxx/
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
drivers/dma/idxd/device.c | 30 ++++-------------------
drivers/dma/idxd/init.c | 51 ++++++++++++++++++++++++++++++++++++---
drivers/dma/idxd/sysfs.c | 7 ------
3 files changed, 52 insertions(+), 36 deletions(-)
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 6fca8fa8d3a8..f6b133d61a04 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -299,21 +299,6 @@ void idxd_wqs_unmap_portal(struct idxd_device *idxd)
}
}
-static void __idxd_wq_set_priv_locked(struct idxd_wq *wq, int priv)
-{
- struct idxd_device *idxd = wq->idxd;
- union wqcfg wqcfg;
- unsigned int offset;
-
- offset = WQCFG_OFFSET(idxd, wq->id, WQCFG_PRIVL_IDX);
- spin_lock(&idxd->dev_lock);
- wqcfg.bits[WQCFG_PRIVL_IDX] = ioread32(idxd->reg_base + offset);
- wqcfg.priv = priv;
- wq->wqcfg->bits[WQCFG_PRIVL_IDX] = wqcfg.bits[WQCFG_PRIVL_IDX];
- iowrite32(wqcfg.bits[WQCFG_PRIVL_IDX], idxd->reg_base + offset);
- spin_unlock(&idxd->dev_lock);
-}
-
static void __idxd_wq_set_pasid_locked(struct idxd_wq *wq, int pasid)
{
struct idxd_device *idxd = wq->idxd;
@@ -1324,15 +1309,14 @@ int drv_enable_wq(struct idxd_wq *wq)
}
/*
- * In the event that the WQ is configurable for pasid and priv bits.
- * For kernel wq, the driver should setup the pasid, pasid_en, and priv bit.
- * However, for non-kernel wq, the driver should only set the pasid_en bit for
- * shared wq. A dedicated wq that is not 'kernel' type will configure pasid and
+ * In the event that the WQ is configurable for pasid, the driver
+ * should setup the pasid, pasid_en bit. This is true for both kernel
+ * and user shared workqueues. There is no need to setup priv bit in
+ * that in-kernel DMA will also do user privileged requests.
+ * A dedicated wq that is not 'kernel' type will configure pasid and
* pasid_en later on so there is no need to setup.
*/
if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
- int priv = 0;
-
if (wq_pasid_enabled(wq)) {
if (is_idxd_wq_kernel(wq) || wq_shared(wq)) {
u32 pasid = wq_dedicated(wq) ? idxd->pasid : 0;
@@ -1340,10 +1324,6 @@ int drv_enable_wq(struct idxd_wq *wq)
__idxd_wq_set_pasid_locked(wq, pasid);
}
}
-
- if (is_idxd_wq_kernel(wq))
- priv = 1;
- __idxd_wq_set_priv_locked(wq, priv);
}
rc = 0;
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index e6ee267da0ff..a3396e1b38f1 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -506,14 +506,56 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev, struct idxd_driver_d
static int idxd_enable_system_pasid(struct idxd_device *idxd)
{
- return -EOPNOTSUPP;
+ struct pci_dev *pdev = idxd->pdev;
+ struct device *dev = &pdev->dev;
+ struct iommu_domain *domain;
+ union gencfg_reg gencfg;
+ ioasid_t pasid;
+ int ret;
+
+ /*
+ * Attach a global PASID to the DMA domain so that we can use ENQCMDS
+ * to submit work on buffers mapped by DMA API.
+ */
+ domain = iommu_get_dma_domain(dev);
+ if (!domain)
+ return -EPERM;
+
+ pasid = iommu_sva_reserve_pasid(1, dev->iommu->max_pasids);
+ if (pasid == IOMMU_PASID_INVALID)
+ return -ENOSPC;
+
+ ret = iommu_attach_device_pasid(domain, dev, pasid);
+ if (ret) {
+ dev_err(dev, "failed to attach device pasid %d, domain type %d",
+ pasid, domain->type);
+ iommu_sva_release_pasid(pasid);
+ return ret;
+ }
+
+ /* Since we set user privilege for kernel DMA, enable completion IRQ */
+ gencfg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
+ gencfg.user_int_en = 1;
+ iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET);
+ idxd->pasid = pasid;
+
+ return ret;
}
static void idxd_disable_system_pasid(struct idxd_device *idxd)
{
+ struct pci_dev *pdev = idxd->pdev;
+ struct device *dev = &pdev->dev;
+ struct iommu_domain *domain;
+
+ domain = iommu_get_domain_for_dev(dev);
+ if (!domain || domain->type == IOMMU_DOMAIN_BLOCKED)
+ return;
- iommu_sva_unbind_device(idxd->sva);
+ iommu_detach_device_pasid(domain, dev, idxd->pasid);
+ iommu_sva_release_pasid(idxd->pasid);
May need gencfg.user_int_en = 0 here.
idxd->sva = NULL;
+ idxd->pasid = IOMMU_PASID_INVALID;
}
static int idxd_probe(struct idxd_device *idxd)
@@ -535,8 +577,9 @@ static int idxd_probe(struct idxd_device *idxd)
} else {
set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
- if (idxd_enable_system_pasid(idxd))
- dev_warn(dev, "No in-kernel DMA with PASID.\n");
+ rc = idxd_enable_system_pasid(idxd);
+ if (rc)
+ dev_warn(dev, "No in-kernel DMA with PASID. %d\n", rc);
else
set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
}
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 18cd8151dee0..c5561c00a503 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -944,13 +944,6 @@ static ssize_t wq_name_store(struct device *dev,
if (strlen(buf) > WQ_NAME_SIZE || strlen(buf) == 0)
return -EINVAL;
- /*
- * This is temporarily placed here until we have SVM support for
- * dmaengine.
- */
- if (wq->type == IDXD_WQT_KERNEL && device_pasid_enabled(wq->idxd))
- return -EOPNOTSUPP;
-
input = kstrndup(buf, count, GFP_KERNEL);
if (!input)
return -ENOMEM;
Thanks.
-Fenghua