Hi Jacob, On 9/20/18 7:21 PM, Jacob Pan wrote: > On Tue, 18 Sep 2018 16:24:38 +0200 > 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 bind and unbind the guest configuration data to the host. >> >> 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> >> >> --- >> >> In practice, I think it would be simpler to have a single >> set_pasid_table function instead of bind/unbind. The "bypass" field >> tells the stage 1 is bypassed (equivalent to the unbind actually). >> On userspace we have notifications that the device context has >> changed. Calling either bind or unbind requires to have an understand >> of what was the previous state and call different notifiers. So to me >> the bind/unbind complexifies the user integration while not bring much >> benefits. >> > I don't have strong preference and I think having a single function > makes sense. In VT-d2, the bind/unbind operation is a result of PASID > cache invalidation from the guest. So there is no symmetrical > bind/unbin user calls. OK thank you for the feedback. > >> This patch generalizes the API introduced by Jacob & co-authors in >> https://lwn.net/Articles/754331/ >> >> v1 -> v2: >> - restore the original pasid table name >> - remove the struct device * parameter in the API >> - reworked iommu_pasid_smmuv3 >> --- >> drivers/iommu/iommu.c | 19 ++++++++++++++ >> include/linux/iommu.h | 21 +++++++++++++++ >> include/uapi/linux/iommu.h | 52 >> ++++++++++++++++++++++++++++++++++++++ 3 files changed, 92 >> insertions(+) create mode 100644 include/uapi/linux/iommu.h >> >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 8c15c5980299..db2c7c9502ae 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -1362,6 +1362,25 @@ int iommu_attach_device(struct iommu_domain >> *domain, struct device *dev) } >> EXPORT_SYMBOL_GPL(iommu_attach_device); >> >> +int iommu_bind_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg) >> +{ >> + if (unlikely(!domain->ops->bind_pasid_table)) >> + return -ENODEV; >> + >> + return domain->ops->bind_pasid_table(domain, cfg); >> +} >> +EXPORT_SYMBOL_GPL(iommu_bind_pasid_table); >> + >> +void iommu_unbind_pasid_table(struct iommu_domain *domain) >> +{ >> + if (unlikely(!domain->ops->unbind_pasid_table)) >> + return; >> + >> + domain->ops->unbind_pasid_table(domain); >> +} >> +EXPORT_SYMBOL_GPL(iommu_unbind_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 87994c265bf5..e56cad4863f7 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) >> @@ -185,6 +186,8 @@ struct iommu_resv_region { >> * @domain_get_windows: Return the number of windows for a domain >> * @of_xlate: add OF master IDs to iommu grouping >> * @pgsize_bitmap: bitmap of all possible supported page sizes >> + * @bind_pasid_table: bind pasid table >> + * @unbind_pasid_table: unbind pasid table and restore defaults >> */ >> struct iommu_ops { >> bool (*capable)(enum iommu_cap); >> @@ -231,6 +234,10 @@ 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 (*bind_pasid_table)(struct iommu_domain *domain, >> + struct iommu_pasid_table_config >> *cfg); >> + void (*unbind_pasid_table)(struct iommu_domain *domain); >> + >> unsigned long pgsize_bitmap; >> }; >> >> @@ -292,6 +299,9 @@ 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_bind_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config >> *cfg); +extern void iommu_unbind_pasid_table(struct iommu_domain >> *domain); extern struct iommu_domain *iommu_get_domain_for_dev(struct >> device *dev); extern int iommu_map(struct iommu_domain *domain, >> unsigned long iova, phys_addr_t paddr, size_t size, int prot); >> @@ -684,6 +694,17 @@ const struct iommu_ops >> *iommu_ops_from_fwnode(struct fwnode_handle *fwnode) return NULL; >> } >> >> +static inline >> +int iommu_bind_pasid_table(struct iommu_domain *domain, >> + struct iommu_pasid_table_config *cfg) >> +{ >> + return -ENODEV; >> +} >> +static inline >> +void iommu_unbind_pasid_table(struct iommu_domain *domain) >> +{ >> +} >> + >> #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..babec91ae7e1 >> --- /dev/null >> +++ b/include/uapi/linux/iommu.h >> @@ -0,0 +1,52 @@ >> +/* 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 >> + * @s1contextptr: Context Descriptor Table GPA >> + * @abort: shall the STE lead to abort >> + * @s1fmt: STE s1fmt field as set by the guest >> + * @s1cdmax: STE s1cdmax 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 { >> + __u64 s1contextptr; >> + __u8 bypass; >> + __u8 abort; >> + __u8 s1fmt; >> + __u8 s1cdmax; >> + __u8 s1dss; >> +}; >> + >> +/** >> + * 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 { > don;t you need some vendor neutral data such as > * @base_ptr: PASID table pointer > * @pasid_bits: number of bits supported in the guest PASID table, must be less > * or equal than the host supported PASID size. At the moment I put those info in the vendor specific struct, ie. iommu_pasid_smmuv3 s1contextptr = base_ptr whereas s1cdmax corresponds to the number of entries pointed by S1contextptr. I am open to moving those fields back to the generic part if their semantic is shared by all the archs. Thanks Eric > > >> +#define PASID_TABLE_CFG_VERSION_1 1 >> + __u32 version; >> +#define IOMMU_PASID_FORMAT_SMMUV3 (1 << 0) >> + __u32 format; >> + union { >> + struct iommu_pasid_smmuv3 smmuv3; >> + }; >> +}; >> + >> +#endif /* _UAPI_IOMMU_H */ >
