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SubjectRe: [PATCH kernel v11 33/34] vfio: powerpc/spapr: Register memory and define IOMMU v2
On Fri, May 29, 2015 at 06:44:57PM +1000, Alexey Kardashevskiy wrote:
> The existing implementation accounts the whole DMA window in
> the locked_vm counter. This is going to be worse with multiple
> containers and huge DMA windows. Also, real-time accounting would requite
> additional tracking of accounted pages due to the page size difference -
> IOMMU uses 4K pages and system uses 4K or 64K pages.
>
> Another issue is that actual pages pinning/unpinning happens on every
> DMA map/unmap request. This does not affect the performance much now as
> we spend way too much time now on switching context between
> guest/userspace/host but this will start to matter when we add in-kernel
> DMA map/unmap acceleration.
>
> This introduces a new IOMMU type for SPAPR - VFIO_SPAPR_TCE_v2_IOMMU.
> New IOMMU deprecates VFIO_IOMMU_ENABLE/VFIO_IOMMU_DISABLE and introduces
> 2 new ioctls to register/unregister DMA memory -
> VFIO_IOMMU_SPAPR_REGISTER_MEMORY and VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY -
> which receive user space address and size of a memory region which
> needs to be pinned/unpinned and counted in locked_vm.
> New IOMMU splits physical pages pinning and TCE table update
> into 2 different operations. It requires:
> 1) guest pages to be registered first
> 2) consequent map/unmap requests to work only with pre-registered memory.
> For the default single window case this means that the entire guest
> (instead of 2GB) needs to be pinned before using VFIO.
> When a huge DMA window is added, no additional pinning will be
> required, otherwise it would be guest RAM + 2GB.
>
> The new memory registration ioctls are not supported by
> VFIO_SPAPR_TCE_IOMMU. Dynamic DMA window and in-kernel acceleration
> will require memory to be preregistered in order to work.
>
> The accounting is done per the user process.
>
> This advertises v2 SPAPR TCE IOMMU and restricts what the userspace
> can do with v1 or v2 IOMMUs.
>
> In order to support memory pre-registration, we need a way to track
> the use of every registered memory region and only allow unregistration
> if a region is not in use anymore. So we need a way to tell from what
> region the just cleared TCE was from.
>
> This adds a userspace view of the TCE table into iommu_table struct.
> It contains userspace address, one per TCE entry. The table is only
> allocated when the ownership over an IOMMU group is taken which means
> it is only used from outside of the powernv code (such as VFIO).
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> [aw: for the vfio related changes]
> Acked-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> Changes:
> v11:
> * mm_iommu_put() does not return a code so this does not check it
> * moved "v2" in tce_container to pack the struct
>
> v10:
> * moved it_userspace allocation to vfio_iommu_spapr_tce as it VFIO
> specific thing
> * squashed "powerpc/iommu: Add userspace view of TCE table" into this as
> it is
> a part of IOMMU v2
> * s/tce_iommu_use_page_v2/tce_iommu_prereg_ua_to_hpa/
> * fixed some function names to have "tce_iommu_" in the beginning rather
> just "tce_"
> * as mm_iommu_mapped_inc() can now fail, check for the return code
>
> v9:
> * s/tce_get_hva_cached/tce_iommu_use_page_v2/
>
> v7:
> * now memory is registered per mm (i.e. process)
> * moved memory registration code to powerpc/mmu
> * merged "vfio: powerpc/spapr: Define v2 IOMMU" into this
> * limited new ioctls to v2 IOMMU
> * updated doc
> * unsupported ioclts return -ENOTTY instead of -EPERM
>
> v6:
> * tce_get_hva_cached() returns hva via a pointer
>
> v4:
> * updated docs
> * s/kzmalloc/vzalloc/
> * in tce_pin_pages()/tce_unpin_pages() removed @vaddr, @size and
> replaced offset with index
> * renamed vfio_iommu_type_register_memory to vfio_iommu_spapr_register_memory
> and removed duplicating vfio_iommu_spapr_register_memory
> ---
> Documentation/vfio.txt | 31 ++-
> arch/powerpc/include/asm/iommu.h | 6 +
> drivers/vfio/vfio_iommu_spapr_tce.c | 512 ++++++++++++++++++++++++++++++------
> include/uapi/linux/vfio.h | 27 ++
> 4 files changed, 487 insertions(+), 89 deletions(-)
>
> diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
> index 96978ec..7dcf2b5 100644
> --- a/Documentation/vfio.txt
> +++ b/Documentation/vfio.txt
> @@ -289,10 +289,12 @@ PPC64 sPAPR implementation note
>
> This implementation has some specifics:
>
> -1) Only one IOMMU group per container is supported as an IOMMU group
> -represents the minimal entity which isolation can be guaranteed for and
> -groups are allocated statically, one per a Partitionable Endpoint (PE)
> +1) On older systems (POWER7 with P5IOC2/IODA1) only one IOMMU group per
> +container is supported as an IOMMU table is allocated at the boot time,
> +one table per a IOMMU group which is a Partitionable Endpoint (PE)
> (PE is often a PCI domain but not always).
> +Newer systems (POWER8 with IODA2) have improved hardware design which allows
> +to remove this limitation and have multiple IOMMU groups per a VFIO container.
>
> 2) The hardware supports so called DMA windows - the PCI address range
> within which DMA transfer is allowed, any attempt to access address space
> @@ -427,6 +429,29 @@ The code flow from the example above should be slightly changed:
>
> ....
>
> +5) There is v2 of SPAPR TCE IOMMU. It deprecates VFIO_IOMMU_ENABLE/
> +VFIO_IOMMU_DISABLE and implements 2 new ioctls:
> +VFIO_IOMMU_SPAPR_REGISTER_MEMORY and VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY
> +(which are unsupported in v1 IOMMU).
> +
> +PPC64 paravirtualized guests generate a lot of map/unmap requests,
> +and the handling of those includes pinning/unpinning pages and updating
> +mm::locked_vm counter to make sure we do not exceed the rlimit.
> +The v2 IOMMU splits accounting and pinning into separate operations:
> +
> +- VFIO_IOMMU_SPAPR_REGISTER_MEMORY/VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY ioctls
> +receive a user space address and size of the block to be pinned.
> +Bisecting is not supported and VFIO_IOMMU_UNREGISTER_MEMORY is expected to
> +be called with the exact address and size used for registering
> +the memory block. The userspace is not expected to call these often.
> +The ranges are stored in a linked list in a VFIO container.
> +
> +- VFIO_IOMMU_MAP_DMA/VFIO_IOMMU_UNMAP_DMA ioctls only update the actual
> +IOMMU table and do not do pinning; instead these check that the userspace
> +address is from pre-registered range.
> +
> +This separation helps in optimizing DMA for guests.
> +
> -------------------------------------------------------------------------------
>
> [1] VFIO was originally an acronym for "Virtual Function I/O" in its
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index 9d37492..f9957eb 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -112,9 +112,15 @@ struct iommu_table {
> unsigned long *it_map; /* A simple allocation bitmap for now */
> unsigned long it_page_shift;/* table iommu page size */
> struct list_head it_group_list;/* List of iommu_table_group_link */
> + unsigned long *it_userspace; /* userspace view of the table */
> struct iommu_table_ops *it_ops;
> };
>
> +#define IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry) \
> + ((tbl)->it_userspace ? \
> + &((tbl)->it_userspace[(entry) - (tbl)->it_offset]) : \
> + NULL)
> +
> /* Pure 2^n version of get_order */
> static inline __attribute_const__
> int get_iommu_order(unsigned long size, struct iommu_table *tbl)
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 7a84110..cadd9f8 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -19,8 +19,10 @@
> #include <linux/uaccess.h>
> #include <linux/err.h>
> #include <linux/vfio.h>
> +#include <linux/vmalloc.h>
> #include <asm/iommu.h>
> #include <asm/tce.h>
> +#include <asm/mmu_context.h>
>
> #define DRIVER_VERSION "0.1"
> #define DRIVER_AUTHOR "aik@ozlabs.ru"
> @@ -81,6 +83,11 @@ static void decrement_locked_vm(long npages)
> * into DMA'ble space using the IOMMU
> */
>
> +struct tce_iommu_group {
> + struct list_head next;
> + struct iommu_group *grp;
> +};
> +
> /*
> * The container descriptor supports only a single group per container.
> * Required by the API as the container is not supplied with the IOMMU group
> @@ -88,11 +95,84 @@ static void decrement_locked_vm(long npages)
> */
> struct tce_container {
> struct mutex lock;
> - struct iommu_group *grp;
> bool enabled;
> + bool v2;
> unsigned long locked_pages;
> + struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
> + struct list_head group_list;
> };
>
> +static long tce_iommu_unregister_pages(struct tce_container *container,
> + __u64 vaddr, __u64 size)
> +{
> + struct mm_iommu_table_group_mem_t *mem;
> +
> + if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
> + return -EINVAL;
> +
> + mem = mm_iommu_lookup(vaddr, size >> PAGE_SHIFT);
> + if (!mem)
> + return -EINVAL;

Uh.. contrary to the commit message this doesn't enforce that the
unregister is called on the exact same vaddr and size as was
registered. Instead a call to unregister will unregister the first
registered region that overlaps with the specified region.

Also, ENOENT might be a better error code for this case (couldn't find
a matching registered region) - EINVAL is rather overused.

> +
> + return mm_iommu_put(mem);
> +}
> +
> +static long tce_iommu_register_pages(struct tce_container *container,
> + __u64 vaddr, __u64 size)
> +{
> + long ret = 0;
> + struct mm_iommu_table_group_mem_t *mem = NULL;
> + unsigned long entries = size >> PAGE_SHIFT;
> +
> + if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK) ||
> + ((vaddr + size) < vaddr))
> + return -EINVAL;
> +
> + ret = mm_iommu_get(vaddr, entries, &mem);
> + if (ret)
> + return ret;
> +
> + container->enabled = true;

I'm assuming that once any region is registered you can no longer add
or remove groups from the container? That's fine but it might want a
more prominent notice in the docs.

> +
> + return 0;
> +}
> +
> +static long tce_iommu_userspace_view_alloc(struct iommu_table *tbl)
> +{
> + unsigned long cb = _ALIGN_UP(sizeof(tbl->it_userspace[0]) *
> + tbl->it_size, PAGE_SIZE);
> + unsigned long *uas;
> + long ret;
> +
> + BUG_ON(tbl->it_userspace);
> +
> + ret = try_increment_locked_vm(cb >> PAGE_SHIFT);
> + if (ret)
> + return ret;
> +
> + uas = vzalloc(cb);
> + if (!uas) {
> + decrement_locked_vm(cb >> PAGE_SHIFT);
> + return -ENOMEM;
> + }
> + tbl->it_userspace = uas;
> +
> + return 0;
> +}
> +
> +static void tce_iommu_userspace_view_free(struct iommu_table *tbl)
> +{
> + unsigned long cb = _ALIGN_UP(sizeof(tbl->it_userspace[0]) *
> + tbl->it_size, PAGE_SIZE);
> +
> + if (!tbl->it_userspace)
> + return;
> +
> + vfree(tbl->it_userspace);
> + tbl->it_userspace = NULL;
> + decrement_locked_vm(cb >> PAGE_SHIFT);
> +}
> +
> static bool tce_page_is_contained(struct page *page, unsigned page_shift)
> {
> /*
> @@ -103,18 +183,18 @@ static bool tce_page_is_contained(struct page *page, unsigned page_shift)
> return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift;
> }
>
> +static inline bool tce_groups_attached(struct tce_container *container)
> +{
> + return !list_empty(&container->group_list);
> +}
> +
> static long tce_iommu_find_table(struct tce_container *container,
> phys_addr_t ioba, struct iommu_table **ptbl)
> {
> long i;
> - struct iommu_table_group *table_group;
> -
> - table_group = iommu_group_get_iommudata(container->grp);
> - if (!table_group)
> - return -1;
>
> for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> - struct iommu_table *tbl = table_group->tables[i];
> + struct iommu_table *tbl = container->tables[i];
>
> if (tbl) {
> unsigned long entry = ioba >> tbl->it_page_shift;
> @@ -136,9 +216,7 @@ static int tce_iommu_enable(struct tce_container *container)
> int ret = 0;
> unsigned long locked;
> struct iommu_table_group *table_group;
> -
> - if (!container->grp)
> - return -ENXIO;
> + struct tce_iommu_group *tcegrp;
> if (!current->mm)
> return -ESRCH; /* process exited */
> @@ -175,7 +253,12 @@ static int tce_iommu_enable(struct tce_container *container)
> * as there is no way to know how much we should increment
> * the locked_vm counter.
> */
> - table_group = iommu_group_get_iommudata(container->grp);
> + if (!tce_groups_attached(container))
> + return -ENODEV;
> +
> + tcegrp = list_first_entry(&container->group_list,
> + struct tce_iommu_group, next);
> + table_group = iommu_group_get_iommudata(tcegrp->grp);
> if (!table_group)
> return -ENODEV;
>
> @@ -211,7 +294,7 @@ static void *tce_iommu_open(unsigned long arg)
> {
> struct tce_container *container;
>
> - if (arg != VFIO_SPAPR_TCE_IOMMU) {
> + if ((arg != VFIO_SPAPR_TCE_IOMMU) && (arg != VFIO_SPAPR_TCE_v2_IOMMU)) {
> pr_err("tce_vfio: Wrong IOMMU type\n");
> return ERR_PTR(-EINVAL);
> }
> @@ -221,18 +304,45 @@ static void *tce_iommu_open(unsigned long arg)
> return ERR_PTR(-ENOMEM);
>
> mutex_init(&container->lock);
> + INIT_LIST_HEAD_RCU(&container->group_list);
> +
> + container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
>
> return container;
> }
>
> +static int tce_iommu_clear(struct tce_container *container,
> + struct iommu_table *tbl,
> + unsigned long entry, unsigned long pages);
> +static void tce_iommu_free_table(struct iommu_table *tbl);
> +
> static void tce_iommu_release(void *iommu_data)
> {
> struct tce_container *container = iommu_data;
> + struct iommu_table_group *table_group;
> + struct tce_iommu_group *tcegrp;
> + long i;
>
> - WARN_ON(container->grp);
> + while (tce_groups_attached(container)) {
> + tcegrp = list_first_entry(&container->group_list,
> + struct tce_iommu_group, next);
> + table_group = iommu_group_get_iommudata(tcegrp->grp);
> + tce_iommu_detach_group(iommu_data, tcegrp->grp);
> + }
>
> - if (container->grp)
> - tce_iommu_detach_group(iommu_data, container->grp);
> + /*
> + * If VFIO created a table, it was not disposed
> + * by tce_iommu_detach_group() so do it now.
> + */
> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> + struct iommu_table *tbl = container->tables[i];
> +
> + if (!tbl)
> + continue;
> +
> + tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> + tce_iommu_free_table(tbl);
> + }
>
> tce_iommu_disable(container);
> mutex_destroy(&container->lock);
> @@ -249,6 +359,47 @@ static void tce_iommu_unuse_page(struct tce_container *container,
> put_page(page);
> }
>
> +static int tce_iommu_prereg_ua_to_hpa(unsigned long tce, unsigned long size,
> + unsigned long *phpa, struct mm_iommu_table_group_mem_t **pmem)
> +{
> + long ret = 0;
> + struct mm_iommu_table_group_mem_t *mem;
> +
> + mem = mm_iommu_lookup(tce, size);
> + if (!mem)
> + return -EINVAL;
> +
> + ret = mm_iommu_ua_to_hpa(mem, tce, phpa);
> + if (ret)
> + return -EINVAL;
> +
> + *pmem = mem;
> +
> + return 0;
> +}
> +
> +static void tce_iommu_unuse_page_v2(struct iommu_table *tbl,
> + unsigned long entry)
> +{
> + struct mm_iommu_table_group_mem_t *mem = NULL;
> + int ret;
> + unsigned long hpa = 0;
> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
> +
> + if (!pua || !current || !current->mm)
> + return;
> +
> + ret = tce_iommu_prereg_ua_to_hpa(*pua, IOMMU_PAGE_SIZE(tbl),
> + &hpa, &mem);
> + if (ret)
> + pr_debug("%s: tce %lx at #%lx was not cached, ret=%d\n",
> + __func__, *pua, entry, ret);
> + if (mem)
> + mm_iommu_mapped_dec(mem);
> +
> + *pua = 0;
> +}
> +
> static int tce_iommu_clear(struct tce_container *container,
> struct iommu_table *tbl,
> unsigned long entry, unsigned long pages)
> @@ -267,6 +418,11 @@ static int tce_iommu_clear(struct tce_container *container,
> if (direction == DMA_NONE)
> continue;
>
> + if (container->v2) {
> + tce_iommu_unuse_page_v2(tbl, entry);
> + continue;
> + }
> +
> tce_iommu_unuse_page(container, oldhpa);
> }
>
> @@ -333,6 +489,64 @@ static long tce_iommu_build(struct tce_container *container,
> return ret;
> }
>
> +static long tce_iommu_build_v2(struct tce_container *container,
> + struct iommu_table *tbl,
> + unsigned long entry, unsigned long tce, unsigned long pages,
> + enum dma_data_direction direction)
> +{
> + long i, ret = 0;
> + struct page *page;
> + unsigned long hpa;
> + enum dma_data_direction dirtmp;
> +
> + for (i = 0; i < pages; ++i) {
> + struct mm_iommu_table_group_mem_t *mem = NULL;
> + unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl,
> + entry + i);
> +
> + ret = tce_iommu_prereg_ua_to_hpa(tce, IOMMU_PAGE_SIZE(tbl),
> + &hpa, &mem);
> + if (ret)
> + break;
> +
> + page = pfn_to_page(hpa >> PAGE_SHIFT);
> + if (!tce_page_is_contained(page, tbl->it_page_shift)) {
> + ret = -EPERM;
> + break;
> + }
> +
> + /* Preserve offset within IOMMU page */
> + hpa |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
> + dirtmp = direction;
> +
> + /* The registered region is being unregistered */
> + if (mm_iommu_mapped_inc(mem))
> + break;
> +
> + ret = iommu_tce_xchg(tbl, entry + i, &hpa, &dirtmp);
> + if (ret) {
> + /* dirtmp cannot be DMA_NONE here */
> + tce_iommu_unuse_page_v2(tbl, entry + i);
> + pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
> + __func__, entry << tbl->it_page_shift,
> + tce, ret);
> + break;
> + }
> +
> + if (dirtmp != DMA_NONE)
> + tce_iommu_unuse_page_v2(tbl, entry + i);
> +
> + *pua = tce;
> +
> + tce += IOMMU_PAGE_SIZE(tbl);
> + }
> +
> + if (ret)
> + tce_iommu_clear(container, tbl, entry, i);
> +
> + return ret;
> +}
> +
> static long tce_iommu_create_table(struct tce_container *container,
> struct iommu_table_group *table_group,
> int num,
> @@ -358,6 +572,12 @@ static long tce_iommu_create_table(struct tce_container *container,
> WARN_ON(!ret && !(*ptbl)->it_ops->free);
> WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size));
>
> + if (!ret && container->v2) {
> + ret = tce_iommu_userspace_view_alloc(*ptbl);
> + if (ret)
> + (*ptbl)->it_ops->free(*ptbl);
> + }
> +
> if (ret)
> decrement_locked_vm(table_size >> PAGE_SHIFT);
>
> @@ -368,6 +588,7 @@ static void tce_iommu_free_table(struct iommu_table *tbl)
> {
> unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
>
> + tce_iommu_userspace_view_free(tbl);
> tbl->it_ops->free(tbl);
> decrement_locked_vm(pages);
> }
> @@ -383,6 +604,7 @@ static long tce_iommu_ioctl(void *iommu_data,
> case VFIO_CHECK_EXTENSION:
> switch (arg) {
> case VFIO_SPAPR_TCE_IOMMU:
> + case VFIO_SPAPR_TCE_v2_IOMMU:
> ret = 1;
> break;
> default:
> @@ -394,12 +616,15 @@ static long tce_iommu_ioctl(void *iommu_data,
>
> case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
> struct vfio_iommu_spapr_tce_info info;
> + struct tce_iommu_group *tcegrp;
> struct iommu_table_group *table_group;
>
> - if (WARN_ON(!container->grp))
> + if (!tce_groups_attached(container))
> return -ENXIO;
>
> - table_group = iommu_group_get_iommudata(container->grp);
> + tcegrp = list_first_entry(&container->group_list,
> + struct tce_iommu_group, next);
> + table_group = iommu_group_get_iommudata(tcegrp->grp);
>
> if (!table_group)
> return -ENXIO;
> @@ -468,11 +693,18 @@ static long tce_iommu_ioctl(void *iommu_data,
> if (ret)
> return ret;
>
> - ret = tce_iommu_build(container, tbl,
> - param.iova >> tbl->it_page_shift,
> - param.vaddr,
> - param.size >> tbl->it_page_shift,
> - direction);
> + if (container->v2)
> + ret = tce_iommu_build_v2(container, tbl,
> + param.iova >> tbl->it_page_shift,
> + param.vaddr,
> + param.size >> tbl->it_page_shift,
> + direction);
> + else
> + ret = tce_iommu_build(container, tbl,
> + param.iova >> tbl->it_page_shift,
> + param.vaddr,
> + param.size >> tbl->it_page_shift,
> + direction);
>
> iommu_flush_tce(tbl);
>
> @@ -518,7 +750,61 @@ static long tce_iommu_ioctl(void *iommu_data,
>
> return ret;
> }
> + case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
> + struct vfio_iommu_spapr_register_memory param;
> +
> + if (!container->v2)
> + break;
> +
> + minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
> + size);
> +
> + if (copy_from_user(&param, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (param.argsz < minsz)
> + return -EINVAL;
> +
> + /* No flag is supported now */
> + if (param.flags)
> + return -EINVAL;
> +
> + mutex_lock(&container->lock);
> + ret = tce_iommu_register_pages(container, param.vaddr,
> + param.size);
> + mutex_unlock(&container->lock);
> +
> + return ret;
> + }
> + case VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY: {
> + struct vfio_iommu_spapr_register_memory param;
> +
> + if (!container->v2)
> + break;
> +
> + minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
> + size);
> +
> + if (copy_from_user(&param, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (param.argsz < minsz)
> + return -EINVAL;
> +
> + /* No flag is supported now */
> + if (param.flags)
> + return -EINVAL;
> +
> + mutex_lock(&container->lock);
> + ret = tce_iommu_unregister_pages(container, param.vaddr, param.size);
> + mutex_unlock(&container->lock);
> +
> + return ret;
> + }
> case VFIO_IOMMU_ENABLE:
> + if (container->v2)
> + break;
> +
> mutex_lock(&container->lock);
> ret = tce_iommu_enable(container);
> mutex_unlock(&container->lock);
> @@ -526,16 +812,27 @@ static long tce_iommu_ioctl(void *iommu_data,
>
>
> case VFIO_IOMMU_DISABLE:
> + if (container->v2)
> + break;
> +
> mutex_lock(&container->lock);
> tce_iommu_disable(container);
> mutex_unlock(&container->lock);
> return 0;
> - case VFIO_EEH_PE_OP:
> - if (!container->grp)
> - return -ENODEV;
>
> - return vfio_spapr_iommu_eeh_ioctl(container->grp,
> - cmd, arg);
> + case VFIO_EEH_PE_OP: {
> + struct tce_iommu_group *tcegrp;
> +
> + ret = 0;
> + list_for_each_entry(tcegrp, &container->group_list, next) {
> + ret = vfio_spapr_iommu_eeh_ioctl(tcegrp->grp,
> + cmd, arg);
> + if (ret)
> + return ret;
> + }
> + return ret;
> + }
> +
> }
>
> return -ENOTTY;
> @@ -547,14 +844,17 @@ static void tce_iommu_release_ownership(struct tce_container *container,
> int i;
>
> for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> - struct iommu_table *tbl = table_group->tables[i];
> + struct iommu_table *tbl = container->tables[i];
>
> if (!tbl)
> continue;
>
> tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> + tce_iommu_userspace_view_free(tbl);
> if (tbl->it_map)
> iommu_release_ownership(tbl);
> +
> + container->tables[i] = NULL;
> }
> }
>
> @@ -569,7 +869,10 @@ static int tce_iommu_take_ownership(struct tce_container *container,
> if (!tbl || !tbl->it_map)
> continue;
>
> - rc = iommu_take_ownership(tbl);
> + rc = tce_iommu_userspace_view_alloc(tbl);
> + if (!rc)
> + rc = iommu_take_ownership(tbl);
> +
> if (rc) {
> for (j = 0; j < i; ++j)
> iommu_release_ownership(
> @@ -579,6 +882,9 @@ static int tce_iommu_take_ownership(struct tce_container *container,
> }
> }
>
> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
> + container->tables[i] = table_group->tables[i];
> +
> return 0;
> }
>
> @@ -592,18 +898,8 @@ static void tce_iommu_release_ownership_ddw(struct tce_container *container,
> return;
> }
>
> - for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> - /* Store table pointer as unset_window resets it */
> - struct iommu_table *tbl = table_group->tables[i];
> -
> - if (!tbl)
> - continue;
> -
> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
> table_group->ops->unset_window(table_group, i);
> - tce_iommu_clear(container, tbl,
> - tbl->it_offset, tbl->it_size);
> - tce_iommu_free_table(tbl);
> - }
>
> table_group->ops->release_ownership(table_group);
> }
> @@ -611,7 +907,7 @@ static void tce_iommu_release_ownership_ddw(struct tce_container *container,
> static long tce_iommu_take_ownership_ddw(struct tce_container *container,
> struct iommu_table_group *table_group)
> {
> - long ret;
> + long i, ret = 0;
> struct iommu_table *tbl = NULL;
>
> if (!table_group->ops->create_table || !table_group->ops->set_window ||
> @@ -622,23 +918,45 @@ static long tce_iommu_take_ownership_ddw(struct tce_container *container,
>
> table_group->ops->take_ownership(table_group);
>
> - ret = tce_iommu_create_table(container,
> - table_group,
> - 0, /* window number */
> - IOMMU_PAGE_SHIFT_4K,
> - table_group->tce32_size,
> - 1, /* default levels */
> - &tbl);
> - if (!ret) {
> - ret = table_group->ops->set_window(table_group, 0, tbl);
> + /*
> + * If it the first group attached, check if there is
> + * a default DMA window and create one if none as
> + * the userspace expects it to exist.

You could choose not to create the 32-bit DMA window by default for v2
containers. But I don't know if that would actually simplify anything.

> + */
> + if (!tce_groups_attached(container) && !container->tables[0]) {
> + ret = tce_iommu_create_table(container,
> + table_group,
> + 0, /* window number */
> + IOMMU_PAGE_SHIFT_4K,
> + table_group->tce32_size,
> + 1, /* default levels */
> + &tbl);
> if (ret)
> - tce_iommu_free_table(tbl);
> + goto release_exit;
> else
> - table_group->tables[0] = tbl;
> + container->tables[0] = tbl;
> }
>
> - if (ret)
> - table_group->ops->release_ownership(table_group);
> + /* Set all windows to the new group */
> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> + tbl = container->tables[i];
> +
> + if (!tbl)
> + continue;
> +
> + /* Set the default window to a new group */
> + ret = table_group->ops->set_window(table_group, i, tbl);
> + if (ret)
> + goto release_exit;
> + }
> +
> + return 0;
> +
> +release_exit:
> + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
> + table_group->ops->unset_window(table_group, i);
> +
> + table_group->ops->release_ownership(table_group);
>
> return ret;
> }
> @@ -649,29 +967,44 @@ static int tce_iommu_attach_group(void *iommu_data,
> int ret;
> struct tce_container *container = iommu_data;
> struct iommu_table_group *table_group;
> + struct tce_iommu_group *tcegrp = NULL;
>
> mutex_lock(&container->lock);
>
> /* pr_debug("tce_vfio: Attaching group #%u to iommu %p\n",
> iommu_group_id(iommu_group), iommu_group); */
> - if (container->grp) {
> - pr_warn("tce_vfio: Only one group per IOMMU container is allowed, existing id=%d, attaching id=%d\n",
> - iommu_group_id(container->grp),
> - iommu_group_id(iommu_group));
> - ret = -EBUSY;
> - goto unlock_exit;
> - }
> -
> - if (container->enabled) {
> - pr_err("tce_vfio: attaching group #%u to enabled container\n",
> - iommu_group_id(iommu_group));
> - ret = -EBUSY;
> - goto unlock_exit;
> - }
> -
> table_group = iommu_group_get_iommudata(iommu_group);
> - if (!table_group) {
> - ret = -ENXIO;
> +
> + if (tce_groups_attached(container) && (!table_group->ops ||
> + !table_group->ops->take_ownership ||
> + !table_group->ops->release_ownership)) {
> + ret = -EBUSY;
> + goto unlock_exit;
> + }
> +
> + /* Check if new group has the same iommu_ops (i.e. compatible) */
> + list_for_each_entry(tcegrp, &container->group_list, next) {
> + struct iommu_table_group *table_group_tmp;
> +
> + if (tcegrp->grp == iommu_group) {
> + pr_warn("tce_vfio: Group %d is already attached\n",
> + iommu_group_id(iommu_group));
> + ret = -EBUSY;
> + goto unlock_exit;
> + }
> + table_group_tmp = iommu_group_get_iommudata(tcegrp->grp);
> + if (table_group_tmp->ops != table_group->ops) {
> + pr_warn("tce_vfio: Group %d is incompatible with group %d\n",
> + iommu_group_id(iommu_group),
> + iommu_group_id(tcegrp->grp));
> + ret = -EPERM;
> + goto unlock_exit;
> + }
> + }
> +
> + tcegrp = kzalloc(sizeof(*tcegrp), GFP_KERNEL);
> + if (!tcegrp) {
> + ret = -ENOMEM;
> goto unlock_exit;
> }
>
> @@ -681,10 +1014,15 @@ static int tce_iommu_attach_group(void *iommu_data,
> else
> ret = tce_iommu_take_ownership_ddw(container, table_group);
>
> - if (!ret)
> - container->grp = iommu_group;
> + if (!ret) {
> + tcegrp->grp = iommu_group;
> + list_add(&tcegrp->next, &container->group_list);
> + }
>
> unlock_exit:
> + if (ret && tcegrp)
> + kfree(tcegrp);
> +
> mutex_unlock(&container->lock);
>
> return ret;
> @@ -695,24 +1033,26 @@ static void tce_iommu_detach_group(void *iommu_data,
> {
> struct tce_container *container = iommu_data;
> struct iommu_table_group *table_group;
> + bool found = false;
> + struct tce_iommu_group *tcegrp;
>
> mutex_lock(&container->lock);
> - if (iommu_group != container->grp) {
> - pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
> - iommu_group_id(iommu_group),
> - iommu_group_id(container->grp));
> +
> + list_for_each_entry(tcegrp, &container->group_list, next) {
> + if (tcegrp->grp == iommu_group) {
> + found = true;
> + break;
> + }
> + }
> +
> + if (!found) {
> + pr_warn("tce_vfio: detaching unattached group #%u\n",
> + iommu_group_id(iommu_group));
> goto unlock_exit;
> }
>
> - if (container->enabled) {
> - pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
> - iommu_group_id(container->grp));
> - tce_iommu_disable(container);
> - }
> -
> - /* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
> - iommu_group_id(iommu_group), iommu_group); */
> - container->grp = NULL;
> + list_del(&tcegrp->next);
> + kfree(tcegrp);
>
> table_group = iommu_group_get_iommudata(iommu_group);
> BUG_ON(!table_group);
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index b57b750..8fdcfb9 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -36,6 +36,8 @@
> /* Two-stage IOMMU */
> #define VFIO_TYPE1_NESTING_IOMMU 6 /* Implies v2 */
>
> +#define VFIO_SPAPR_TCE_v2_IOMMU 7
> +
> /*
> * The IOCTL interface is designed for extensibility by embedding the
> * structure length (argsz) and flags into structures passed between
> @@ -495,6 +497,31 @@ struct vfio_eeh_pe_op {
>
> #define VFIO_EEH_PE_OP _IO(VFIO_TYPE, VFIO_BASE + 21)
>
> +/**
> + * VFIO_IOMMU_SPAPR_REGISTER_MEMORY - _IOW(VFIO_TYPE, VFIO_BASE + 17, struct vfio_iommu_spapr_register_memory)
> + *
> + * Registers user space memory where DMA is allowed. It pins
> + * user pages and does the locked memory accounting so
> + * subsequent VFIO_IOMMU_MAP_DMA/VFIO_IOMMU_UNMAP_DMA calls
> + * get faster.
> + */
> +struct vfio_iommu_spapr_register_memory {
> + __u32 argsz;
> + __u32 flags;
> + __u64 vaddr; /* Process virtual address */
> + __u64 size; /* Size of mapping (bytes) */
> +};
> +#define VFIO_IOMMU_SPAPR_REGISTER_MEMORY _IO(VFIO_TYPE, VFIO_BASE + 17)
> +
> +/**
> + * VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY - _IOW(VFIO_TYPE, VFIO_BASE + 18, struct vfio_iommu_spapr_register_memory)
> + *
> + * Unregisters user space memory registered with
> + * VFIO_IOMMU_SPAPR_REGISTER_MEMORY.
> + * Uses vfio_iommu_spapr_register_memory for parameters.
> + */
> +#define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY _IO(VFIO_TYPE, VFIO_BASE + 18)
> +
> /* ***************************************************************** */
>
> #endif /* _UAPIVFIO_H */

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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