| 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 |
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
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 --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);