diff mbox series

[RESEND,v9,03/13] iommu/sva: Add PASID helpers

Message ID 20200817171558.325917-4-jean-philippe@linaro.org (mailing list archive)
State New, archived
Headers show
Series iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part) | expand

Commit Message

Jean-Philippe Brucker Aug. 17, 2020, 5:15 p.m. UTC 
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 <jean-philippe@linaro.org>
---
 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.c

Comments

Eric Auger Sept. 8, 2020, 7:45 a.m. UTC | #1 
Hi Jean,

On 8/17/20 7:15 PM, Jean-Philippe Brucker wrote:
> 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 <jean-philippe@linaro.org>
> ---
>  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.c
> 
> diff --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 PCI
> diff --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.o
> diff --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
Jean-Philippe Brucker Sept. 17, 2020, 2:36 p.m. UTC | #2 
On Tue, Sep 08, 2020 at 09:45:02AM +0200, Auger Eric wrote:
> > +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.

Right, I'll add to the function doc "@min must be greater than 0 because
0 indicates an unused mm->pasid."

> > +		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?

Ok

Thanks,
Jean

> > +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
>
diff mbox series

Patch

diff --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 PCI
diff --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.o
diff --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)
+		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;
+	mutex_unlock(&iommu_sva_lock);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_free_pasid);
+
+/* ioasid wants a void * argument */
+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);