Hi Alex, On 1/11/19 7:43 PM, Alex Williamson wrote: > On Tue, 8 Jan 2019 11:26:13 +0100 > Eric Auger <eric.auger@xxxxxxxxxx> wrote: > >> From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> >> >> In virtualization use case, when a guest is assigned >> a PCI host device, protected by a virtual IOMMU on a guest, >> the physical IOMMU must be programmed to be consistent with >> the guest mappings. If the physical IOMMU supports two >> translation stages it makes sense to program guest mappings >> onto the first stage/level (ARM/VTD terminology) while to host >> owns the stage/level 2. >> >> In that case, it is mandated to trap on guest configuration >> settings and pass those to the physical iommu driver. >> >> This patch adds a new API to the iommu subsystem that allows >> to set the pasid table information. >> >> A generic iommu_pasid_table_config struct is introduced in >> a new iommu.h uapi header. This is going to be used by the VFIO >> user API. We foresee at least two specializations of this struct, >> for PASID table passing and ARM SMMUv3. >> >> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> >> Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx> >> Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx> >> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> >> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> >> >> --- >> >> This patch generalizes the API introduced by Jacob & co-authors in >> https://lwn.net/Articles/754331/ >> >> v2 -> v3: >> - replace unbind/bind by set_pasid_table >> - move table pointer and pasid bits in the generic part of the struct >> >> v1 -> v2: >> - restore the original pasid table name >> - remove the struct device * parameter in the API >> - reworked iommu_pasid_smmuv3 >> --- >> drivers/iommu/iommu.c | 10 ++++++++ >> include/linux/iommu.h | 14 +++++++++++ >> include/uapi/linux/iommu.h | 50 ++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 74 insertions(+) >> create mode 100644 include/uapi/linux/iommu.h >> >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 3ed4db334341..0f2b7f1fc7c8 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -1393,6 +1393,16 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev) >> } >> EXPORT_SYMBOL_GPL(iommu_attach_device); >> >> +int iommu_set_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg) >> +{ >> + if (unlikely(!domain->ops->set_pasid_table)) >> + return -ENODEV; >> + >> + return domain->ops->set_pasid_table(domain, cfg); >> +} >> +EXPORT_SYMBOL_GPL(iommu_set_pasid_table); >> + >> static void __iommu_detach_device(struct iommu_domain *domain, >> struct device *dev) >> { >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index e90da6b6f3d1..1da2a2357ea4 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -25,6 +25,7 @@ >> #include <linux/errno.h> >> #include <linux/err.h> >> #include <linux/of.h> >> +#include <uapi/linux/iommu.h> >> >> #define IOMMU_READ (1 << 0) >> #define IOMMU_WRITE (1 << 1) >> @@ -184,6 +185,7 @@ struct iommu_resv_region { >> * @domain_window_disable: Disable a particular window for a domain >> * @of_xlate: add OF master IDs to iommu grouping >> * @pgsize_bitmap: bitmap of all possible supported page sizes >> + * @set_pasid_table: set pasid table >> */ >> struct iommu_ops { >> bool (*capable)(enum iommu_cap); >> @@ -226,6 +228,9 @@ struct iommu_ops { >> int (*of_xlate)(struct device *dev, struct of_phandle_args *args); >> bool (*is_attach_deferred)(struct iommu_domain *domain, struct device *dev); >> >> + int (*set_pasid_table)(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg); >> + >> unsigned long pgsize_bitmap; >> }; >> >> @@ -287,6 +292,8 @@ extern int iommu_attach_device(struct iommu_domain *domain, >> struct device *dev); >> extern void iommu_detach_device(struct iommu_domain *domain, >> struct device *dev); >> +extern int iommu_set_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg); >> extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev); >> extern struct iommu_domain *iommu_get_dma_domain(struct device *dev); >> extern int iommu_map(struct iommu_domain *domain, unsigned long iova, >> @@ -696,6 +703,13 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode) >> return NULL; >> } >> >> +static inline >> +int iommu_set_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg) >> +{ >> + return -ENODEV; >> +} >> + >> #endif /* CONFIG_IOMMU_API */ >> >> #ifdef CONFIG_IOMMU_DEBUGFS >> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h >> new file mode 100644 >> index 000000000000..7a7cf7a3de7c >> --- /dev/null >> +++ b/include/uapi/linux/iommu.h >> @@ -0,0 +1,50 @@ >> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ >> +/* >> + * IOMMU user API definitions >> + * >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + */ >> + >> +#ifndef _UAPI_IOMMU_H >> +#define _UAPI_IOMMU_H >> + >> +#include <linux/types.h> >> + >> +/** >> + * SMMUv3 Stream Table Entry stage 1 related information >> + * @abort: shall the STE lead to abort >> + * @s1fmt: STE s1fmt field as set by the guest >> + * @s1dss: STE s1dss as set by the guest >> + * All field names match the smmu 3.0/3.1 spec (ARM IHI 0070A) >> + */ >> +struct iommu_pasid_smmuv3 { >> + __u8 abort; >> + __u8 s1fmt; >> + __u8 s1dss; >> +}; >> + > > I can find STE.S1DSS and STE.S1FMT in the spec, but not STE.ABORT, is > this something to do with Config[2:0]? Are we allowed to describe what > these fields are beyond their name and why they're necessary here vs > the other fields or do the spec restrictions preclude that? Yes you're right abort matches !Config[2] what about: /** * SMMUv3 Stream Table Entry stage 1 related information * The PASID table is referred to as the context descriptor (CD) table. * * @s1fmt: STE s1fmt (format of the CD table: single CD, linear table or 2-level table) * @s1dss: STE s1dss (specifies the behavior when pasid_bits != 0 an no pasid is passed along with the incoming transaction) * Please refer to the smmu 3.x spec (ARM IHI 0070A) for full details */ struct iommu_pasid_smmuv3 { #define PASID_TABLE_SMMUV3_CFG_VERSION_1 1 __u32 version; __u8 s1fmt; __u8 s1dss; __u8 padding[2]; }; > >> +/** >> + * PASID table data used to bind guest PASID table to the host IOMMU >> + * Note PASID table corresponds to the Context Table on ARM SMMUv3. >> + * >> + * @version: API version to prepare for future extensions >> + * @format: format of the PASID table >> + * >> + */ >> +struct iommu_pasid_table_config { >> +#define PASID_TABLE_CFG_VERSION_1 1 >> + __u32 version; >> +#define IOMMU_PASID_FORMAT_SMMUV3 (1 << 0) >> + __u32 format; >> + __u64 base_ptr; >> + __u8 pasid_bits; >> + __u8 bypass; >> + union { >> + struct iommu_pasid_smmuv3 smmuv3; >> + }; >> +}; > > Structure is not naturally aligned or explicitly aligned for > interchange with userspace. It might work for smmuv3 since the > structure is only composed of bytes, but looks troublesome in general. > Should each format type also contain a version? Is format intended to > be a bit-field or a signature? It seems we only need a signature, but > only having a single format defined, it looks like a bit-field, which > makes me worry what we do when we exhaust the bits. I think a signature is what we need. The bypass field > should be better defined, is it 0/1? zero/non-zero? more selective? I suggest to replace by a signature config field (bypass, abort, translate) Thanks Eric > Thanks, > > Alex > >> + >> +#endif /* _UAPI_IOMMU_H */ >
