RE: [PATCH v3 04/14] vfio: Add PASID allocation/free support
Hi Alex, > From: Alex Williamson > Sent: Friday, July 3, 2020 5:17 AM > > On Wed, 24 Jun 2020 01:55:17 -0700 > Liu Yi L wrote: > > > Shared Virtual Addressing (a.k.a Shared Virtual Memory) allows sharing > > multiple process virtual address spaces with the device for simplified > > programming model. PASID is used to tag an virtual address space in > > DMA requests and to identify the related translation structure in > > IOMMU. When a PASID-capable device is assigned to a VM, we want the > > same capability of using PASID to tag guest process virtual address > > spaces to achieve virtual SVA (vSVA). > > > > PASID management for guest is vendor specific. Some vendors (e.g. > > Intel > > VT-d) requires system-wide managed PASIDs cross all devices, > > regardless of whether a device is used by host or assigned to guest. > > Other vendors (e.g. ARM SMMU) may allow PASIDs managed per-device thus > > could be fully delegated to the guest for assigned devices. > > > > For system-wide managed PASIDs, this patch introduces a vfio module to > > handle explicit PASID alloc/free requests from guest. Allocated PASIDs > > are associated to a process (or, mm_struct) in IOASID core. A vfio_mm > > object is introduced to track mm_struct. Multiple VFIO containers > > within a process share the same vfio_mm object. > > > > A quota mechanism is provided to prevent malicious user from > > exhausting available PASIDs. Currently the quota is a global parameter > > applied to all VFIO devices. In the future per-device quota might be > > supported > too. > > > > Cc: Kevin Tian > > CC: Jacob Pan > > Cc: Eric Auger > > Cc: Jean-Philippe Brucker > > Cc: Joerg Roedel > > Cc: Lu Baolu > > Suggested-by: Alex Williamson > > Signed-off-by: Liu Yi L > > --- > > v1 -> v2: > > *) added in v2, split from the pasid alloc/free support of v1 > > --- > > drivers/vfio/Kconfig | 5 ++ > > drivers/vfio/Makefile | 1 + > > drivers/vfio/vfio_pasid.c | 151 > ++ > > include/linux/vfio.h | 28 + > > 4 files changed, 185 insertions(+) > > create mode 100644 drivers/vfio/vfio_pasid.c > > > > diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig index > > fd17db9..3d8a108 100644 > > --- a/drivers/vfio/Kconfig > > +++ b/drivers/vfio/Kconfig > > @@ -19,6 +19,11 @@ config VFIO_VIRQFD > > depends on VFIO && EVENTFD > > default n > > > > +config VFIO_PASID > > + tristate > > + depends on IOASID && VFIO > > + default n > > + > > menuconfig VFIO > > tristate "VFIO Non-Privileged userspace driver framework" > > depends on IOMMU_API > > diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile index > > de67c47..bb836a3 100644 > > --- a/drivers/vfio/Makefile > > +++ b/drivers/vfio/Makefile > > @@ -3,6 +3,7 @@ vfio_virqfd-y := virqfd.o > > > > obj-$(CONFIG_VFIO) += vfio.o > > obj-$(CONFIG_VFIO_VIRQFD) += vfio_virqfd.o > > +obj-$(CONFIG_VFIO_PASID) += vfio_pasid.o > > obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o > > obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o > > obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o diff --git > > a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c new file mode > > 100644 index 000..dd5b6d1 > > --- /dev/null > > +++ b/drivers/vfio/vfio_pasid.c > > @@ -0,0 +1,151 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Copyright (C) 2020 Intel Corporation. > > + * Author: Liu Yi L > > + * > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#define DRIVER_VERSION "0.1" > > +#define DRIVER_AUTHOR "Liu Yi L " > > +#define DRIVER_DESC "PASID management for VFIO bus drivers" > > + > > +#define VFIO_DEFAULT_PASID_QUOTA 1000 > > +static int pasid_quota = VFIO_DEFAULT_PASID_QUOTA; > > +module_param_named(pasid_quota, pasid_quota, uint, 0444); > > +MODULE_PARM_DESC(pasid_quota, > > +" Set the quota for max number of PASIDs that an application is > > +allowed to request (default 1000)"); > > + > > +struct vfio_mm_token { > > + unsigned long long val; > > +}; > > + > > +struct vfio_mm { > > + struct kref kref; > > + struct vfio_mm_tokentoken; > > + int ioasid_sid; > > + int pasid_quota; > > + struct list_headnext; > > +}; > > + > > +static struct vfio_pasid { > > + struct mutexvfio_mm_lock; > > + struct list_headvfio_mm_list; > > +} vfio_pasid; > > + > > +/* called with vfio.vfio_mm_lock held */ static void > > +vfio_mm_release(struct kref *kref) { > > + struct vfio_mm *vmm = container_of(kref, struct vfio_mm, kref); > > + > > + list_del(>next); > > + mutex_unlock(_pasid.vfio_mm_lock); > > + ioasid_free_set(vmm->ioasid_sid, true); > > + kfree(vmm); > > +} > > + > > +void vfio_mm_put(struct vfio_mm *vmm) { > > + kref_put_mutex(>kref, vfio_mm_release, > > +_pasid.vfio_mm_lock); } > > + > >
Re: [PATCH v3 04/14] vfio: Add PASID allocation/free support
On Wed, 24 Jun 2020 01:55:17 -0700 Liu Yi L wrote: > Shared Virtual Addressing (a.k.a Shared Virtual Memory) allows sharing > multiple process virtual address spaces with the device for simplified > programming model. PASID is used to tag an virtual address space in DMA > requests and to identify the related translation structure in IOMMU. When > a PASID-capable device is assigned to a VM, we want the same capability > of using PASID to tag guest process virtual address spaces to achieve > virtual SVA (vSVA). > > PASID management for guest is vendor specific. Some vendors (e.g. Intel > VT-d) requires system-wide managed PASIDs cross all devices, regardless > of whether a device is used by host or assigned to guest. Other vendors > (e.g. ARM SMMU) may allow PASIDs managed per-device thus could be fully > delegated to the guest for assigned devices. > > For system-wide managed PASIDs, this patch introduces a vfio module to > handle explicit PASID alloc/free requests from guest. Allocated PASIDs > are associated to a process (or, mm_struct) in IOASID core. A vfio_mm > object is introduced to track mm_struct. Multiple VFIO containers within > a process share the same vfio_mm object. > > A quota mechanism is provided to prevent malicious user from exhausting > available PASIDs. Currently the quota is a global parameter applied to > all VFIO devices. In the future per-device quota might be supported too. > > Cc: Kevin Tian > CC: Jacob Pan > Cc: Eric Auger > Cc: Jean-Philippe Brucker > Cc: Joerg Roedel > Cc: Lu Baolu > Suggested-by: Alex Williamson > Signed-off-by: Liu Yi L > --- > v1 -> v2: > *) added in v2, split from the pasid alloc/free support of v1 > --- > drivers/vfio/Kconfig | 5 ++ > drivers/vfio/Makefile | 1 + > drivers/vfio/vfio_pasid.c | 151 > ++ > include/linux/vfio.h | 28 + > 4 files changed, 185 insertions(+) > create mode 100644 drivers/vfio/vfio_pasid.c > > diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig > index fd17db9..3d8a108 100644 > --- a/drivers/vfio/Kconfig > +++ b/drivers/vfio/Kconfig > @@ -19,6 +19,11 @@ config VFIO_VIRQFD > depends on VFIO && EVENTFD > default n > > +config VFIO_PASID > + tristate > + depends on IOASID && VFIO > + default n > + > menuconfig VFIO > tristate "VFIO Non-Privileged userspace driver framework" > depends on IOMMU_API > diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile > index de67c47..bb836a3 100644 > --- a/drivers/vfio/Makefile > +++ b/drivers/vfio/Makefile > @@ -3,6 +3,7 @@ vfio_virqfd-y := virqfd.o > > obj-$(CONFIG_VFIO) += vfio.o > obj-$(CONFIG_VFIO_VIRQFD) += vfio_virqfd.o > +obj-$(CONFIG_VFIO_PASID) += vfio_pasid.o > obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o > obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o > obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o > diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c > new file mode 100644 > index 000..dd5b6d1 > --- /dev/null > +++ b/drivers/vfio/vfio_pasid.c > @@ -0,0 +1,151 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2020 Intel Corporation. > + * Author: Liu Yi L > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRIVER_VERSION "0.1" > +#define DRIVER_AUTHOR "Liu Yi L " > +#define DRIVER_DESC "PASID management for VFIO bus drivers" > + > +#define VFIO_DEFAULT_PASID_QUOTA 1000 > +static int pasid_quota = VFIO_DEFAULT_PASID_QUOTA; > +module_param_named(pasid_quota, pasid_quota, uint, 0444); > +MODULE_PARM_DESC(pasid_quota, > + " Set the quota for max number of PASIDs that an application > is allowed to request (default 1000)"); > + > +struct vfio_mm_token { > + unsigned long long val; > +}; > + > +struct vfio_mm { > + struct kref kref; > + struct vfio_mm_tokentoken; > + int ioasid_sid; > + int pasid_quota; > + struct list_headnext; > +}; > + > +static struct vfio_pasid { > + struct mutexvfio_mm_lock; > + struct list_headvfio_mm_list; > +} vfio_pasid; > + > +/* called with vfio.vfio_mm_lock held */ > +static void vfio_mm_release(struct kref *kref) > +{ > + struct vfio_mm *vmm = container_of(kref, struct vfio_mm, kref); > + > + list_del(>next); > + mutex_unlock(_pasid.vfio_mm_lock); > + ioasid_free_set(vmm->ioasid_sid, true); > + kfree(vmm); > +} > + > +void vfio_mm_put(struct vfio_mm *vmm) > +{ > + kref_put_mutex(>kref, vfio_mm_release, _pasid.vfio_mm_lock); > +} > + > +static void vfio_mm_get(struct vfio_mm *vmm) > +{ > + kref_get(>kref); > +} > + > +struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task) > +{ > + struct mm_struct *mm = get_task_mm(task); > + struct vfio_mm *vmm; > + unsigned long long val = (unsigned long long) mm; > +