Re: [PATCH RESEND v9 03/13] iommu/sva: Add PASID helpers
From: Auger Eric <eric.auger@redhat.com>
Date: 2020-09-08 07:45:14
Also in:
linux-iommu, linux-mm
Hi Jean, On 8/17/20 7:15 PM, Jean-Philippe Brucker wrote:
quoted hunk ↗ jump to hunk
Let IOMMU drivers allocate a single PASID per mm. Store the mm in the IOASID set to allow refcounting and searching mm by PASID, when handling an I/O page fault. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Jean-Philippe Brucker <redacted> --- drivers/iommu/Kconfig | 5 +++ drivers/iommu/Makefile | 1 + drivers/iommu/iommu-sva-lib.h | 15 +++++++ drivers/iommu/iommu-sva-lib.c | 85 +++++++++++++++++++++++++++++++++++ 4 files changed, 106 insertions(+) create mode 100644 drivers/iommu/iommu-sva-lib.h create mode 100644 drivers/iommu/iommu-sva-lib.cdiff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index bef5d75e306b..fb1787377eb6 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig@@ -103,6 +103,11 @@ config IOMMU_DMA select IRQ_MSI_IOMMU select NEED_SG_DMA_LENGTH +# Shared Virtual Addressing library +config IOMMU_SVA_LIB + bool + select IOASID + config FSL_PAMU bool "Freescale IOMMU support" depends on PCIdiff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile index 11f1771104f3..61bd30cd8369 100644 --- a/drivers/iommu/Makefile +++ b/drivers/iommu/Makefile@@ -27,3 +27,4 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o obj-$(CONFIG_S390_IOMMU) += s390-iommu.o obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o +obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.odiff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h new file mode 100644 index 000000000000..b40990aef3fd --- /dev/null +++ b/drivers/iommu/iommu-sva-lib.h@@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * SVA library for IOMMU drivers + */ +#ifndef _IOMMU_SVA_LIB_H +#define _IOMMU_SVA_LIB_H + +#include <linux/ioasid.h> +#include <linux/mm_types.h> + +int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max); +void iommu_sva_free_pasid(struct mm_struct *mm); +struct mm_struct *iommu_sva_find(ioasid_t pasid); + +#endif /* _IOMMU_SVA_LIB_H */diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c new file mode 100644 index 000000000000..db7e6c104d6b --- /dev/null +++ b/drivers/iommu/iommu-sva-lib.c@@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Helpers for IOMMU drivers implementing SVA + */ +#include <linux/mutex.h> +#include <linux/sched/mm.h> + +#include "iommu-sva-lib.h" + +static DEFINE_MUTEX(iommu_sva_lock); +static DECLARE_IOASID_SET(iommu_sva_pasid); + +/** + * iommu_sva_alloc_pasid - Allocate a PASID for the mm + * @mm: the mm + * @min: minimum PASID value (inclusive) + * @max: maximum PASID value (inclusive) + * + * Try to allocate a PASID for this mm, or take a reference to the existing one + * provided it fits within the [min, max] range. On success the PASID is + * available in mm->pasid, and must be released with iommu_sva_free_pasid(). + * + * Returns 0 on success and < 0 on error. + */ +int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) +{ + int ret = 0; + ioasid_t pasid; + + if (min == INVALID_IOASID || max == INVALID_IOASID || + min == 0 || max < min)
you may add a comment explaining why min == 0 is forbidden.
+ return -EINVAL;
+
+ mutex_lock(&iommu_sva_lock);
+ if (mm->pasid) {
+ if (mm->pasid >= min && mm->pasid <= max)
+ ioasid_get(mm->pasid);
+ else
+ ret = -EOVERFLOW;
+ } else {
+ pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
+ if (pasid == INVALID_IOASID)
+ ret = -ENOMEM;
+ else
+ mm->pasid = pasid;
+ }
+ mutex_unlock(&iommu_sva_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
+
+/**
+ * iommu_sva_free_pasid - Release the mm's PASID
+ * @mm: the mm.
+ *
+ * Drop one reference to a PASID allocated with iommu_sva_alloc_pasid()
+ */
+void iommu_sva_free_pasid(struct mm_struct *mm)
+{
+ mutex_lock(&iommu_sva_lock);
+ if (ioasid_put(mm->pasid))
+ mm->pasid = 0;ditto: 0 versus INVALID_IOASID
+ mutex_unlock(&iommu_sva_lock); +} +EXPORT_SYMBOL_GPL(iommu_sva_free_pasid); + +/* ioasid wants a void * argument */
shouldn't it be: ioasid_find getter() requires a void *arg?
+static bool __mmget_not_zero(void *mm)
+{
+ return mmget_not_zero(mm);
+}
+
+/**
+ * iommu_sva_find() - Find mm associated to the given PASID
+ * @pasid: Process Address Space ID assigned to the mm
+ *
+ * On success a reference to the mm is taken, and must be released with mmput().
+ *
+ * Returns the mm corresponding to this PASID, or an error if not found.
+ */
+struct mm_struct *iommu_sva_find(ioasid_t pasid)
+{
+ return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_find);Thanks Eric _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel