[PATCH kernel v6 00/29] powerpc/iommu/vfio: Enable Dynamic DMA windows

[PATCH kernel v6 00/29] powerpc/iommu/vfio: Enable Dynamic DMA windows

[Alexey Kardashevskiy]

This enables sPAPR defined feature called Dynamic DMA windows (DDW).

Each Partitionable Endpoint (IOMMU group) has an address range on a PCI bus
where devices are allowed to do DMA. These ranges are called DMA windows.
By default, there is a single DMA window, 1 or 2GB big, mapped at zero
on a PCI bus.

Hi-speed devices may suffer from the limited size of the window.
The recent host kernels use a TCE bypass window on POWER8 CPU which implements
direct PCI bus address range mapping (with offset of 1<<59) to the host memory.

For guests, PAPR defines a DDW RTAS API which allows pseries guests
querying the hypervisor about DDW support and capabilities (page size mask
for now). A pseries guest may request an additional (to the default)
DMA windows using this RTAS API.
The existing pseries Linux guests request an additional window as big as
the guest RAM and map the entire guest window which effectively creates
direct mapping of the guest memory to a PCI bus.

The multiple DMA windows feature is supported by POWER7/POWER8 CPUs; however
this patchset only adds support for POWER8 as TCE tables are implemented
in POWER7 in a quite different way ans POWER7 is not the highest priority.

This patchset reworks PPC64 IOMMU code and adds necessary structures
to support big windows.

Once a Linux guest discovers the presence of DDW, it does:
1. query hypervisor about number of available windows and page size masks;
2. create a window with the biggest possible page size (today 4K/64K/16M);
3. map the entire guest RAM via H_PUT_TCE* hypercalls;
4. switche dma_ops to direct_dma_ops on the selected PE.

Once this is done, H_PUT_TCE is not called anymore for 64bit devices and
the guest does not waste time on DMA map/unmap operations.

Note that 32bit devices won't use DDW and will keep using the default
DMA window so KVM optimizations will be required (to be posted later).

The actual version of this patchset is available at:
git@github.com:aik/linux.git , vfio-for-github branch

The matching QEMU version is there:
git@github.com:aik/qemu.git , vfio-for-github branch


Please comment. Thanks!


Changes:
v6:
* fixed a bunch of errors in "vfio: powerpc/spapr: Support Dynamic DMA windows"
* moved static IOMMU properties from iommu_table_group to iommu_table_group_ops
* enforced v1/v2 specific limitations
* added descriptions to new ioctls
* replaced page kind-of-masks from PAPR with normal page mask

v5:
* added SPAPR_TCE_IOMMU_v2 to tell the userspace that there is a memory
pre-registration feature
* added backward compatibility
* renamed few things (mostly powerpc_iommu -> iommu_table_group)

v4:
* moved patches around to have VFIO and PPC patches separated as much as
possible
* now works with the existing upstream QEMU

v3:
* redesigned the whole thing
* multiple IOMMU groups per PHB -> one PHB is needed for VFIO in the guest ->
no problems with locked_vm counting; also we save memory on actual tables
* guest RAM preregistration is required for DDW
* PEs (IOMMU groups) are passed to VFIO with no DMA windows at all so
we do not bother with iommu_table::it_map anymore
* added multilevel TCE tables support to support really huge guests

v2:
* added missing __pa() in "powerpc/powernv: Release replaced TCE"
* reposted to make some noise




Alexey Kardashevskiy (29):
  vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU
    driver
  vfio: powerpc/spapr: Do cleanup when releasing the group
  vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size
  vfio: powerpc/spapr: Use it_page_size
  vfio: powerpc/spapr: Move locked_vm accounting to helpers
  vfio: powerpc/spapr: Disable DMA mappings on disabled container
  vfio: powerpc/spapr: Moving pinning/unpinning to helpers
  vfio: powerpc/spapr: Register memory
  vfio: powerpc/spapr: Rework attach/detach
  powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
  powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table
  powerpc/iommu: Introduce iommu_table_alloc() helper
  powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group
  vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control
  vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework IOMMU ownership
    control
  powerpc/iommu: Fix IOMMU ownership control functions
  powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free()
  powerpc/iommu/powernv: Release replaced TCE
  powerpc/powernv/ioda2: Rework iommu_table creation
  powerpc/powernv/ioda2: Introduce
    pnv_pci_ioda2_create_table/pnc_pci_free_table
  powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window
  powerpc/iommu: Split iommu_free_table into 2 helpers
  powerpc/powernv: Implement multilevel TCE tables
  powerpc/powernv: Change prototypes to receive iommu
  powerpc/powernv/ioda: Define and implement DMA table/window management
    callbacks
  vfio: powerpc/spapr: Define v2 IOMMU
  vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership
  vfio: powerpc/spapr: Support multiple groups in one container if
    possible
  vfio: powerpc/spapr: Support Dynamic DMA windows

 Documentation/vfio.txt                      |   38 +
 arch/powerpc/include/asm/iommu.h            |   98 ++-
 arch/powerpc/include/asm/machdep.h          |   25 -
 arch/powerpc/kernel/iommu.c                 |  328 +++++----
 arch/powerpc/kernel/vio.c                   |    5 +
 arch/powerpc/platforms/cell/iommu.c         |    8 +-
 arch/powerpc/platforms/pasemi/iommu.c       |    7 +-
 arch/powerpc/platforms/powernv/pci-ioda.c   |  499 ++++++++++---
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |   31 +-
 arch/powerpc/platforms/powernv/pci.c        |  114 ++-
 arch/powerpc/platforms/powernv/pci.h        |   12 +-
 arch/powerpc/platforms/pseries/iommu.c      |   55 +-
 arch/powerpc/sysdev/dart_iommu.c            |   12 +-
 drivers/vfio/vfio_iommu_spapr_tce.c         | 1047 ++++++++++++++++++++++++---
 include/uapi/linux/vfio.h                   |   68 +-
 15 files changed, 1862 insertions(+), 485 deletions(-)

-- 
2.0.0

[PATCH kernel v6 01/29] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver

[Alexey Kardashevskiy]

This moves page pinning (get_user_pages_fast()/put_page()) code out of
the platform IOMMU code and puts it to VFIO IOMMU driver where it belongs
to as the platform code does not deal with page pinning.

This makes iommu_take_ownership()/iommu_release_ownership() deal with
the IOMMU table bitmap only.

This removes page unpinning from iommu_take_ownership() as the actual
TCE table might contain garbage and doing put_page() on it is undefined
behaviour.

Besides the last part, the rest of the patch is mechanical.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v4:
* s/iommu_tce_build(tbl, entry + 1/iommu_tce_build(tbl, entry + i/
---
 arch/powerpc/include/asm/iommu.h    |  4 --
 arch/powerpc/kernel/iommu.c         | 55 --------------------------
 drivers/vfio/vfio_iommu_spapr_tce.c | 78 ++++++++++++++++++++++++++++++-------
 3 files changed, 65 insertions(+), 72 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index f1ea597..ed69b7d 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -197,10 +197,6 @@ extern int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 		unsigned long hwaddr, enum dma_data_direction direction);
 extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
 		unsigned long entry);
-extern int iommu_clear_tces_and_put_pages(struct iommu_table *tbl,
-		unsigned long entry, unsigned long pages);
-extern int iommu_put_tce_user_mode(struct iommu_table *tbl,
-		unsigned long entry, unsigned long tce);
 
 extern void iommu_flush_tce(struct iommu_table *tbl);
 extern int iommu_take_ownership(struct iommu_table *tbl);
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index b054f33..1b4a178 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -991,30 +991,6 @@ unsigned long iommu_clear_tce(struct iommu_table *tbl, unsigned long entry)
 }
 EXPORT_SYMBOL_GPL(iommu_clear_tce);
 
-int iommu_clear_tces_and_put_pages(struct iommu_table *tbl,
-		unsigned long entry, unsigned long pages)
-{
-	unsigned long oldtce;
-	struct page *page;
-
-	for ( ; pages; --pages, ++entry) {
-		oldtce = iommu_clear_tce(tbl, entry);
-		if (!oldtce)
-			continue;
-
-		page = pfn_to_page(oldtce >> PAGE_SHIFT);
-		WARN_ON(!page);
-		if (page) {
-			if (oldtce & TCE_PCI_WRITE)
-				SetPageDirty(page);
-			put_page(page);
-		}
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(iommu_clear_tces_and_put_pages);
-
 /*
  * hwaddr is a kernel virtual address here (0xc... bazillion),
  * tce_build converts it to a physical address.
@@ -1044,35 +1020,6 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 }
 EXPORT_SYMBOL_GPL(iommu_tce_build);
 
-int iommu_put_tce_user_mode(struct iommu_table *tbl, unsigned long entry,
-		unsigned long tce)
-{
-	int ret;
-	struct page *page = NULL;
-	unsigned long hwaddr, offset = tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
-	enum dma_data_direction direction = iommu_tce_direction(tce);
-
-	ret = get_user_pages_fast(tce & PAGE_MASK, 1,
-			direction != DMA_TO_DEVICE, &page);
-	if (unlikely(ret != 1)) {
-		/* pr_err("iommu_tce: get_user_pages_fast failed tce=%lx ioba=%lx ret=%d\n",
-				tce, entry << tbl->it_page_shift, ret); */
-		return -EFAULT;
-	}
-	hwaddr = (unsigned long) page_address(page) + offset;
-
-	ret = iommu_tce_build(tbl, entry, hwaddr, direction);
-	if (ret)
-		put_page(page);
-
-	if (ret < 0)
-		pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%d\n",
-			__func__, entry << tbl->it_page_shift, tce, ret);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
-
 int iommu_take_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
@@ -1086,7 +1033,6 @@ int iommu_take_ownership(struct iommu_table *tbl)
 	}
 
 	memset(tbl->it_map, 0xff, sz);
-	iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
 
 	/*
 	 * Disable iommu bypass, otherwise the user can DMA to all of
@@ -1104,7 +1050,6 @@ void iommu_release_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
 
-	iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
 	memset(tbl->it_map, 0, sz);
 
 	/* Restore bit#0 set by iommu_init_table() */
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 20abc3a..6c59339 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -149,6 +149,66 @@ static void tce_iommu_release(void *iommu_data)
 	kfree(container);
 }
 
+static int tce_iommu_clear(struct tce_container *container,
+		struct iommu_table *tbl,
+		unsigned long entry, unsigned long pages)
+{
+	unsigned long oldtce;
+	struct page *page;
+
+	for ( ; pages; --pages, ++entry) {
+		oldtce = iommu_clear_tce(tbl, entry);
+		if (!oldtce)
+			continue;
+
+		page = pfn_to_page(oldtce >> PAGE_SHIFT);
+		WARN_ON(!page);
+		if (page) {
+			if (oldtce & TCE_PCI_WRITE)
+				SetPageDirty(page);
+			put_page(page);
+		}
+	}
+
+	return 0;
+}
+
+static long tce_iommu_build(struct tce_container *container,
+		struct iommu_table *tbl,
+		unsigned long entry, unsigned long tce, unsigned long pages)
+{
+	long i, ret = 0;
+	struct page *page = NULL;
+	unsigned long hva;
+	enum dma_data_direction direction = iommu_tce_direction(tce);
+
+	for (i = 0; i < pages; ++i) {
+		ret = get_user_pages_fast(tce & PAGE_MASK, 1,
+				direction != DMA_TO_DEVICE, &page);
+		if (unlikely(ret != 1)) {
+			ret = -EFAULT;
+			break;
+		}
+		hva = (unsigned long) page_address(page) +
+			(tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK);
+
+		ret = iommu_tce_build(tbl, entry + i, hva, direction);
+		if (ret) {
+			put_page(page);
+			pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
+					__func__, entry << tbl->it_page_shift,
+					tce, ret);
+			break;
+		}
+		tce += IOMMU_PAGE_SIZE_4K;
+	}
+
+	if (ret)
+		tce_iommu_clear(container, tbl, entry, i);
+
+	return ret;
+}
+
 static long tce_iommu_ioctl(void *iommu_data,
 				 unsigned int cmd, unsigned long arg)
 {
@@ -197,7 +257,7 @@ static long tce_iommu_ioctl(void *iommu_data,
 	case VFIO_IOMMU_MAP_DMA: {
 		struct vfio_iommu_type1_dma_map param;
 		struct iommu_table *tbl = container->tbl;
-		unsigned long tce, i;
+		unsigned long tce;
 
 		if (!tbl)
 			return -ENXIO;
@@ -231,17 +291,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (ret)
 			return ret;
 
-		for (i = 0; i < (param.size >> IOMMU_PAGE_SHIFT_4K); ++i) {
-			ret = iommu_put_tce_user_mode(tbl,
-					(param.iova >> IOMMU_PAGE_SHIFT_4K) + i,
-					tce);
-			if (ret)
-				break;
-			tce += IOMMU_PAGE_SIZE_4K;
-		}
-		if (ret)
-			iommu_clear_tces_and_put_pages(tbl,
-					param.iova >> IOMMU_PAGE_SHIFT_4K, i);
+		ret = tce_iommu_build(container, tbl,
+				param.iova >> IOMMU_PAGE_SHIFT_4K,
+				tce, param.size >> IOMMU_PAGE_SHIFT_4K);
 
 		iommu_flush_tce(tbl);
 
@@ -275,7 +327,7 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (ret)
 			return ret;
 
-		ret = iommu_clear_tces_and_put_pages(tbl,
+		ret = tce_iommu_clear(container, tbl,
 				param.iova >> IOMMU_PAGE_SHIFT_4K,
 				param.size >> IOMMU_PAGE_SHIFT_4K);
 		iommu_flush_tce(tbl);
-- 
2.0.0

[PATCH kernel v6 02/29] vfio: powerpc/spapr: Do cleanup when releasing the group

[Alexey Kardashevskiy]

This clears the TCE table when a container is being closed as this is
a good thing to leave the table clean before passing the ownership
back to the host kernel.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 6c59339..756831f 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -134,16 +134,24 @@ static void *tce_iommu_open(unsigned long arg)
 	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_release(void *iommu_data)
 {
 	struct tce_container *container = iommu_data;
+	struct iommu_table *tbl = container->tbl;
 
-	WARN_ON(container->tbl && !container->tbl->it_group);
+	WARN_ON(tbl && !tbl->it_group);
 	tce_iommu_disable(container);
 
-	if (container->tbl && container->tbl->it_group)
-		tce_iommu_detach_group(iommu_data, container->tbl->it_group);
+	if (tbl) {
+		tce_iommu_clear(container, tbl,	tbl->it_offset, tbl->it_size);
 
+		if (tbl->it_group)
+			tce_iommu_detach_group(iommu_data, tbl->it_group);
+	}
 	mutex_destroy(&container->lock);
 
 	kfree(container);
-- 
2.0.0

[PATCH kernel v6 03/29] vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size

[Alexey Kardashevskiy]

This checks that the TCE table page size is not bigger that the size of
a page we just pinned and going to put its physical address to the table.

Otherwise the hardware gets unwanted access to physical memory between
the end of the actual page and the end of the aligned up TCE page.

Since compound_order() and compound_head() work correctly on non-huge
pages, there is no need for additional check whether the page is huge.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v6:
* the helper is simplified to one line

v4:
* s/tce_check_page_size/tce_page_is_contained/
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 756831f..4716b97 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -49,6 +49,16 @@ struct tce_container {
 	bool enabled;
 };
 
+static bool tce_page_is_contained(struct page *page, unsigned page_shift)
+{
+	/*
+	 * Check that the TCE table granularity is not bigger than the size of
+	 * a page we just found. Otherwise the hardware can get access to
+	 * a bigger memory chunk that it should.
+	 */
+	return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift;
+}
+
 static int tce_iommu_enable(struct tce_container *container)
 {
 	int ret = 0;
@@ -197,6 +207,12 @@ static long tce_iommu_build(struct tce_container *container,
 			ret = -EFAULT;
 			break;
 		}
+
+		if (!tce_page_is_contained(page, tbl->it_page_shift)) {
+			ret = -EPERM;
+			break;
+		}
+
 		hva = (unsigned long) page_address(page) +
 			(tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK);
 
-- 
2.0.0

[PATCH kernel v6 04/29] vfio: powerpc/spapr: Use it_page_size

[Alexey Kardashevskiy]

This makes use of the it_page_size from the iommu_table struct
as page size can differ.

This replaces missing IOMMU_PAGE_SHIFT macro in commented debug code
as recently introduced IOMMU_PAGE_XXX macros do not include
IOMMU_PAGE_SHIFT.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 4716b97..431e605 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -93,7 +93,7 @@ static int tce_iommu_enable(struct tce_container *container)
 	 * enforcing the limit based on the max that the guest can map.
 	 */
 	down_write(&current->mm->mmap_sem);
-	npages = (tbl->it_size << IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
+	npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
 	locked = current->mm->locked_vm + npages;
 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 	if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
@@ -122,7 +122,7 @@ static void tce_iommu_disable(struct tce_container *container)
 
 	down_write(&current->mm->mmap_sem);
 	current->mm->locked_vm -= (container->tbl->it_size <<
-			IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
+			container->tbl->it_page_shift) >> PAGE_SHIFT;
 	up_write(&current->mm->mmap_sem);
 }
 
@@ -224,7 +224,7 @@ static long tce_iommu_build(struct tce_container *container,
 					tce, ret);
 			break;
 		}
-		tce += IOMMU_PAGE_SIZE_4K;
+		tce += IOMMU_PAGE_SIZE(tbl);
 	}
 
 	if (ret)
@@ -269,8 +269,8 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT_4K;
-		info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT_4K;
+		info.dma32_window_start = tbl->it_offset << tbl->it_page_shift;
+		info.dma32_window_size = tbl->it_size << tbl->it_page_shift;
 		info.flags = 0;
 
 		if (copy_to_user((void __user *)arg, &info, minsz))
@@ -300,8 +300,8 @@ static long tce_iommu_ioctl(void *iommu_data,
 				VFIO_DMA_MAP_FLAG_WRITE))
 			return -EINVAL;
 
-		if ((param.size & ~IOMMU_PAGE_MASK_4K) ||
-				(param.vaddr & ~IOMMU_PAGE_MASK_4K))
+		if ((param.size & ~IOMMU_PAGE_MASK(tbl)) ||
+				(param.vaddr & ~IOMMU_PAGE_MASK(tbl)))
 			return -EINVAL;
 
 		/* iova is checked by the IOMMU API */
@@ -316,8 +316,8 @@ static long tce_iommu_ioctl(void *iommu_data,
 			return ret;
 
 		ret = tce_iommu_build(container, tbl,
-				param.iova >> IOMMU_PAGE_SHIFT_4K,
-				tce, param.size >> IOMMU_PAGE_SHIFT_4K);
+				param.iova >> tbl->it_page_shift,
+				tce, param.size >> tbl->it_page_shift);
 
 		iommu_flush_tce(tbl);
 
@@ -343,17 +343,17 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (param.flags)
 			return -EINVAL;
 
-		if (param.size & ~IOMMU_PAGE_MASK_4K)
+		if (param.size & ~IOMMU_PAGE_MASK(tbl))
 			return -EINVAL;
 
 		ret = iommu_tce_clear_param_check(tbl, param.iova, 0,
-				param.size >> IOMMU_PAGE_SHIFT_4K);
+				param.size >> tbl->it_page_shift);
 		if (ret)
 			return ret;
 
 		ret = tce_iommu_clear(container, tbl,
-				param.iova >> IOMMU_PAGE_SHIFT_4K,
-				param.size >> IOMMU_PAGE_SHIFT_4K);
+				param.iova >> tbl->it_page_shift,
+				param.size >> tbl->it_page_shift);
 		iommu_flush_tce(tbl);
 
 		return ret;
-- 
2.0.0

[PATCH kernel v6 05/29] vfio: powerpc/spapr: Move locked_vm accounting to helpers

[Alexey Kardashevskiy]

There moves locked pages accounting to helpers.
Later they will be reused for Dynamic DMA windows (DDW).

This reworks debug messages to show the current value and the limit.

This stores the locked pages number in the container so when unlocking
the iommu table pointer won't be needed. This does not have an effect
now but it will with the multiple tables per container as then we will
allow attaching/detaching groups on fly and we may end up having
a container with no group attached but with the counter incremented.

While we are here, update the comment explaining why RLIMIT_MEMLOCK
might be required to be bigger than the guest RAM. This also prints
pid of the current process in pr_warn/pr_debug.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v4:
* new helpers do nothing if @npages == 0
* tce_iommu_disable() now can decrement the counter if the group was
detached (not possible now but will be in the future)
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 82 ++++++++++++++++++++++++++++---------
 1 file changed, 63 insertions(+), 19 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 431e605..c47b969 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -31,6 +31,51 @@
 static void tce_iommu_detach_group(void *iommu_data,
 		struct iommu_group *iommu_group);
 
+static long try_increment_locked_vm(long npages)
+{
+	long ret = 0, locked, lock_limit;
+
+	if (!current || !current->mm)
+		return -ESRCH; /* process exited */
+
+	if (!npages)
+		return 0;
+
+	down_write(&current->mm->mmap_sem);
+	locked = current->mm->locked_vm + npages;
+	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	if (locked > lock_limit && !capable(CAP_IPC_LOCK))
+		ret = -ENOMEM;
+	else
+		current->mm->locked_vm += npages;
+
+	pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid,
+			npages << PAGE_SHIFT,
+			current->mm->locked_vm << PAGE_SHIFT,
+			rlimit(RLIMIT_MEMLOCK),
+			ret ? " - exceeded" : "");
+
+	up_write(&current->mm->mmap_sem);
+
+	return ret;
+}
+
+static void decrement_locked_vm(long npages)
+{
+	if (!current || !current->mm || !npages)
+		return; /* process exited */
+
+	down_write(&current->mm->mmap_sem);
+	if (npages > current->mm->locked_vm)
+		npages = current->mm->locked_vm;
+	current->mm->locked_vm -= npages;
+	pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid,
+			npages << PAGE_SHIFT,
+			current->mm->locked_vm << PAGE_SHIFT,
+			rlimit(RLIMIT_MEMLOCK));
+	up_write(&current->mm->mmap_sem);
+}
+
 /*
  * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
  *
@@ -47,6 +92,7 @@ struct tce_container {
 	struct mutex lock;
 	struct iommu_table *tbl;
 	bool enabled;
+	unsigned long locked_pages;
 };
 
 static bool tce_page_is_contained(struct page *page, unsigned page_shift)
@@ -62,7 +108,7 @@ static bool tce_page_is_contained(struct page *page, unsigned page_shift)
 static int tce_iommu_enable(struct tce_container *container)
 {
 	int ret = 0;
-	unsigned long locked, lock_limit, npages;
+	unsigned long locked;
 	struct iommu_table *tbl = container->tbl;
 
 	if (!container->tbl)
@@ -91,21 +137,22 @@ static int tce_iommu_enable(struct tce_container *container)
 	 * Also we don't have a nice way to fail on H_PUT_TCE due to ulimits,
 	 * that would effectively kill the guest at random points, much better
 	 * enforcing the limit based on the max that the guest can map.
+	 *
+	 * Unfortunately at the moment it counts whole tables, no matter how
+	 * much memory the guest has. I.e. for 4GB guest and 4 IOMMU groups
+	 * each with 2GB DMA window, 8GB will be counted here. The reason for
+	 * this is that we cannot tell here the amount of RAM used by the guest
+	 * as this information is only available from KVM and VFIO is
+	 * KVM agnostic.
 	 */
-	down_write(&current->mm->mmap_sem);
-	npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
-	locked = current->mm->locked_vm + npages;
-	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-	if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
-		pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n",
-				rlimit(RLIMIT_MEMLOCK));
-		ret = -ENOMEM;
-	} else {
+	locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
+	ret = try_increment_locked_vm(locked);
+	if (ret)
+		return ret;
 
-		current->mm->locked_vm += npages;
-		container->enabled = true;
-	}
-	up_write(&current->mm->mmap_sem);
+	container->locked_pages = locked;
+
+	container->enabled = true;
 
 	return ret;
 }
@@ -117,13 +164,10 @@ static void tce_iommu_disable(struct tce_container *container)
 
 	container->enabled = false;
 
-	if (!container->tbl || !current->mm)
+	if (!current->mm)
 		return;
 
-	down_write(&current->mm->mmap_sem);
-	current->mm->locked_vm -= (container->tbl->it_size <<
-			container->tbl->it_page_shift) >> PAGE_SHIFT;
-	up_write(&current->mm->mmap_sem);
+	decrement_locked_vm(container->locked_pages);
 }
 
 static void *tce_iommu_open(unsigned long arg)
-- 
2.0.0

[PATCH kernel v6 06/29] vfio: powerpc/spapr: Disable DMA mappings on disabled container

[Alexey Kardashevskiy]

At the moment DMA map/unmap requests are handled irrespective to
the container's state. This allows the user space to pin memory which
it might not be allowed to pin.

This adds checks to MAP/UNMAP that the container is enabled, otherwise
-EPERM is returned.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index c47b969..8a667cb 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -327,6 +327,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 		struct iommu_table *tbl = container->tbl;
 		unsigned long tce;
 
+		if (!container->enabled)
+			return -EPERM;
+
 		if (!tbl)
 			return -ENXIO;
 
@@ -371,6 +374,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 		struct vfio_iommu_type1_dma_unmap param;
 		struct iommu_table *tbl = container->tbl;
 
+		if (!container->enabled)
+			return -EPERM;
+
 		if (WARN_ON(!tbl))
 			return -ENXIO;
 
-- 
2.0.0

[PATCH kernel v6 07/29] vfio: powerpc/spapr: Moving pinning/unpinning to helpers

[Alexey Kardashevskiy]

This is a pretty mechanical patch to make next patches simpler.

New tce_iommu_unuse_page() helper does put_page() now but it might skip
that after the memory registering patch applied.

As we are here, this removes unnecessary checks for a value returned
by pfn_to_page() as it cannot possibly return NULL.

This moves tce_iommu_disable() later to let tce_iommu_clear() know if
the container has been enabled because if it has not been, then
put_page() must not be called on TCEs from the TCE table. This situation
is not yet possible but it will after KVM acceleration patchset is
applied.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v6:
* tce_get_hva() returns hva via a pointer
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 69 +++++++++++++++++++++++++++----------
 1 file changed, 51 insertions(+), 18 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 8a667cb..be693ca 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -198,7 +198,6 @@ static void tce_iommu_release(void *iommu_data)
 	struct iommu_table *tbl = container->tbl;
 
 	WARN_ON(tbl && !tbl->it_group);
-	tce_iommu_disable(container);
 
 	if (tbl) {
 		tce_iommu_clear(container, tbl,	tbl->it_offset, tbl->it_size);
@@ -206,63 +205,97 @@ static void tce_iommu_release(void *iommu_data)
 		if (tbl->it_group)
 			tce_iommu_detach_group(iommu_data, tbl->it_group);
 	}
+
+	tce_iommu_disable(container);
+
 	mutex_destroy(&container->lock);
 
 	kfree(container);
 }
 
+static void tce_iommu_unuse_page(struct tce_container *container,
+		unsigned long oldtce)
+{
+	struct page *page;
+
+	if (!(oldtce & (TCE_PCI_READ | TCE_PCI_WRITE)))
+		return;
+
+	/*
+	 * VFIO cannot map/unmap when a container is not enabled so
+	 * we would not need this check but KVM could map/unmap and if
+	 * this happened, we must not put pages as KVM does not get them as
+	 * it expects memory pre-registation to do this part.
+	 */
+	if (!container->enabled)
+		return;
+
+	page = pfn_to_page(__pa(oldtce) >> PAGE_SHIFT);
+
+	if (oldtce & TCE_PCI_WRITE)
+		SetPageDirty(page);
+
+	put_page(page);
+}
+
 static int tce_iommu_clear(struct tce_container *container,
 		struct iommu_table *tbl,
 		unsigned long entry, unsigned long pages)
 {
 	unsigned long oldtce;
-	struct page *page;
 
 	for ( ; pages; --pages, ++entry) {
 		oldtce = iommu_clear_tce(tbl, entry);
 		if (!oldtce)
 			continue;
 
-		page = pfn_to_page(oldtce >> PAGE_SHIFT);
-		WARN_ON(!page);
-		if (page) {
-			if (oldtce & TCE_PCI_WRITE)
-				SetPageDirty(page);
-			put_page(page);
-		}
+		tce_iommu_unuse_page(container, (unsigned long) __va(oldtce));
 	}
 
 	return 0;
 }
 
+static int tce_get_hva(struct tce_container *container,
+		unsigned page_shift, unsigned long tce, unsigned long *hva)
+{
+	struct page *page = NULL;
+	enum dma_data_direction direction = iommu_tce_direction(tce);
+
+	if (get_user_pages_fast(tce & PAGE_MASK, 1,
+			direction != DMA_TO_DEVICE, &page) != 1)
+		return -EFAULT;
+
+	*hva = (unsigned long) page_address(page);
+
+	return 0;
+}
+
 static long tce_iommu_build(struct tce_container *container,
 		struct iommu_table *tbl,
 		unsigned long entry, unsigned long tce, unsigned long pages)
 {
 	long i, ret = 0;
-	struct page *page = NULL;
+	struct page *page;
 	unsigned long hva;
 	enum dma_data_direction direction = iommu_tce_direction(tce);
 
 	for (i = 0; i < pages; ++i) {
-		ret = get_user_pages_fast(tce & PAGE_MASK, 1,
-				direction != DMA_TO_DEVICE, &page);
-		if (unlikely(ret != 1)) {
-			ret = -EFAULT;
+		ret = tce_get_hva(container, tbl->it_page_shift, tce, &hva);
+		if (ret)
 			break;
-		}
 
+		page = pfn_to_page(__pa(hva) >> PAGE_SHIFT);
 		if (!tce_page_is_contained(page, tbl->it_page_shift)) {
 			ret = -EPERM;
 			break;
 		}
 
-		hva = (unsigned long) page_address(page) +
-			(tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK);
+		/* Preserve offset within IOMMU page */
+		hva |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
 
 		ret = iommu_tce_build(tbl, entry + i, hva, direction);
 		if (ret) {
-			put_page(page);
+			tce_iommu_unuse_page(container, hva);
 			pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
 					__func__, entry << tbl->it_page_shift,
 					tce, ret);
-- 
2.0.0

[PATCH kernel v6 08/29] vfio: powerpc/spapr: Register memory

[Alexey Kardashevskiy]

The existing implementation accounts the whole DMA window in
the locked_vm counter which is going to be even worse with multiple
containers and huge DMA windows.

This introduces 2 ioctls to register/unregister DMA memory which
receive user space address and size of a memory region which
needs to be pinned/unpinned and counted in locked_vm.

If any memory region was registered, all subsequent DMA map requests
should address already pinned memory. If no memory was registered,
then the amount of memory required for a single default memory will be
accounted when the container is enabled and every map/unmap will pin/unpin
a page (with degraded performance).

Dynamic DMA window and in-kernel acceleration will require memory to
be preregistered in order to work.

The accounting is done per VFIO container. When support for
multiple groups per container is added, we will have more accurate locked_vm
accounting.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
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              |  19 +++
 drivers/vfio/vfio_iommu_spapr_tce.c | 275 +++++++++++++++++++++++++++++++++++-
 include/uapi/linux/vfio.h           |  25 ++++
 3 files changed, 313 insertions(+), 6 deletions(-)

diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
index 96978ec..791e85c 100644
--- a/Documentation/vfio.txt
+++ b/Documentation/vfio.txt
@@ -427,6 +427,25 @@ The code flow from the example above should be slightly changed:
 
 	....
 
+5) PPC64 paravirtualized guests may 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. Handling these
+in real-mode is quite expensive and may fail. In order to simplify in-kernel
+acceleration of map/unmap requests, two ioctls have been added to pre-register
+and unregister guest RAM pages where DMA can possibly happen to. Having these
+calles, the userspace and in-kernel handlers do not have to take care of
+pinning or accounting.
+
+The ioctls are VFIO_IOMMU_SPAPR_REGISTER_MEMORY and
+VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY.
+These 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 user space is not expected to call these often and the block descriptors
+are stored in a linked list in the kernel.
+
 -------------------------------------------------------------------------------
 
 [1] VFIO was originally an acronym for "Virtual Function I/O" in its
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index be693ca..838123e 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -21,6 +21,7 @@
 #include <linux/uaccess.h>
 #include <linux/err.h>
 #include <linux/vfio.h>
+#include <linux/vmalloc.h>
 #include <asm/iommu.h>
 #include <asm/tce.h>
 
@@ -93,8 +94,196 @@ struct tce_container {
 	struct iommu_table *tbl;
 	bool enabled;
 	unsigned long locked_pages;
+	struct list_head mem_list;
 };
 
+struct tce_memory {
+	struct list_head next;
+	struct rcu_head rcu;
+	__u64 vaddr;
+	__u64 size;
+	__u64 hpas[];
+};
+
+static inline bool tce_preregistered(struct tce_container *container)
+{
+	return !list_empty(&container->mem_list);
+}
+
+static struct tce_memory *tce_mem_alloc(struct tce_container *container,
+		__u64 vaddr, __u64 size)
+{
+	struct tce_memory *mem;
+	long ret;
+
+	ret = try_increment_locked_vm(size >> PAGE_SHIFT);
+	if (ret)
+		return NULL;
+
+	mem = vzalloc(sizeof(*mem) + (size >> (PAGE_SHIFT - 3)));
+	if (!mem) {
+		decrement_locked_vm(size >> PAGE_SHIFT);
+		return NULL;
+	}
+
+	mem->vaddr = vaddr;
+	mem->size = size;
+
+	list_add_rcu(&mem->next, &container->mem_list);
+
+	return mem;
+}
+
+static void release_tce_memory(struct rcu_head *head)
+{
+	struct tce_memory *mem = container_of(head, struct tce_memory, rcu);
+
+	vfree(mem);
+}
+
+static void tce_mem_free(struct tce_memory *mem)
+{
+	decrement_locked_vm(mem->size);
+	list_del_rcu(&mem->next);
+	call_rcu(&mem->rcu, release_tce_memory);
+}
+
+static struct tce_memory *tce_pinned_desc(struct tce_container *container,
+		__u64 vaddr, __u64 size)
+{
+	struct tce_memory *mem, *ret = NULL;
+
+	rcu_read_lock();
+	vaddr &= ~(TCE_PCI_READ | TCE_PCI_WRITE);
+	list_for_each_entry_rcu(mem, &container->mem_list, next) {
+		if ((mem->vaddr <= vaddr) &&
+				(vaddr + size <= mem->vaddr + mem->size)) {
+			ret = mem;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static bool tce_mem_overlapped(struct tce_container *container,
+		__u64 vaddr, __u64 size)
+{
+	struct tce_memory *mem;
+	bool ret = false;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(mem, &container->mem_list, next) {
+		if ((mem->vaddr < (vaddr + size)) &&
+				(vaddr < (mem->vaddr + mem->size))) {
+			ret = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static void tce_unpin_pages(struct tce_container *container,
+		struct tce_memory *mem)
+{
+	long i;
+	struct page *page = NULL;
+
+	for (i = 0; i < (mem->size >> PAGE_SHIFT); ++i) {
+		if (!mem->hpas[i])
+			continue;
+
+		page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT);
+		if (!page)
+			continue;
+
+		put_page(page);
+		mem->hpas[i] = 0;
+	}
+}
+
+static long tce_unregister_pages(struct tce_container *container,
+		__u64 vaddr, __u64 size)
+{
+	struct tce_memory *mem, *memtmp;
+
+	if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
+		return -EINVAL;
+
+	list_for_each_entry_safe(mem, memtmp, &container->mem_list, next) {
+		if ((mem->vaddr == vaddr) && (mem->size == size)) {
+			tce_unpin_pages(container, mem);
+			tce_mem_free(mem);
+
+			/* If that was the last region, disable the container */
+			if (!tce_preregistered(container))
+				container->enabled = false;
+
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static void tce_mem_unregister_all(struct tce_container *container)
+{
+	struct tce_memory *mem, *memtmp;
+
+	list_for_each_entry_safe(mem, memtmp, &container->mem_list, next) {
+		tce_unpin_pages(container, mem);
+		tce_mem_free(mem);
+	}
+}
+
+static long tce_pin_pages(struct tce_container *container,
+		struct tce_memory *mem)
+{
+	long i;
+	struct page *page = NULL;
+
+	for (i = 0; i < (mem->size >> PAGE_SHIFT); ++i) {
+		if (1 != get_user_pages_fast(mem->vaddr + (i << PAGE_SHIFT),
+					1/* pages */, 1/* iswrite */, &page)) {
+			tce_unpin_pages(container, mem);
+			return -EFAULT;
+		}
+
+		mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT;
+	}
+
+	return 0;
+}
+
+static long tce_register_pages(struct tce_container *container,
+		__u64 vaddr, __u64 size)
+{
+	struct tce_memory *mem;
+
+	if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK) ||
+			((vaddr + size) < vaddr))
+		return -EINVAL;
+
+	if (tce_mem_overlapped(container, vaddr, size))
+		return -EBUSY;
+
+	mem = tce_mem_alloc(container, vaddr, size);
+	if (!mem)
+		return -ENOMEM;
+
+	if (tce_pin_pages(container, mem)) {
+		tce_mem_free(mem);
+		return -EFAULT;
+	}
+
+	container->enabled = true;
+
+	return 0;
+}
+
 static bool tce_page_is_contained(struct page *page, unsigned page_shift)
 {
 	/*
@@ -145,12 +334,14 @@ static int tce_iommu_enable(struct tce_container *container)
 	 * as this information is only available from KVM and VFIO is
 	 * KVM agnostic.
 	 */
-	locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
-	ret = try_increment_locked_vm(locked);
-	if (ret)
-		return ret;
+	if (!tce_preregistered(container)) {
+		locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
+		ret = try_increment_locked_vm(locked);
+		if (ret)
+			return ret;
 
-	container->locked_pages = locked;
+		container->locked_pages = locked;
+	}
 
 	container->enabled = true;
 
@@ -184,6 +375,7 @@ static void *tce_iommu_open(unsigned long arg)
 		return ERR_PTR(-ENOMEM);
 
 	mutex_init(&container->lock);
+	INIT_LIST_HEAD_RCU(&container->mem_list);
 
 	return container;
 }
@@ -206,6 +398,7 @@ static void tce_iommu_release(void *iommu_data)
 			tce_iommu_detach_group(iommu_data, tbl->it_group);
 	}
 
+	tce_mem_unregister_all(container);
 	tce_iommu_disable(container);
 
 	mutex_destroy(&container->lock);
@@ -235,6 +428,9 @@ static void tce_iommu_unuse_page(struct tce_container *container,
 	if (oldtce & TCE_PCI_WRITE)
 		SetPageDirty(page);
 
+	if (tce_preregistered(container))
+		return;
+
 	put_page(page);
 }
 
@@ -270,6 +466,24 @@ static int tce_get_hva(struct tce_container *container,
 	return 0;
 }
 
+static int tce_get_hva_cached(struct tce_container *container,
+		unsigned page_shift, unsigned long tce, unsigned long *hva)
+{
+	struct tce_memory *mem;
+	unsigned long gfn;
+
+	tce &= PAGE_MASK;
+	mem = tce_pinned_desc(container, tce, 1ULL << page_shift);
+	if (!mem)
+		return -EFAULT;
+
+	gfn = (tce - mem->vaddr) >> PAGE_SHIFT;
+
+	*hva = (unsigned long) __va(mem->hpas[gfn]);
+
+	return 0;
+}
+
 static long tce_iommu_build(struct tce_container *container,
 		struct iommu_table *tbl,
 		unsigned long entry, unsigned long tce, unsigned long pages)
@@ -280,7 +494,12 @@ static long tce_iommu_build(struct tce_container *container,
 	enum dma_data_direction direction = iommu_tce_direction(tce);
 
 	for (i = 0; i < pages; ++i) {
-		ret = tce_get_hva(container, tbl->it_page_shift, tce, &hva);
+		if (tce_preregistered(container))
+			ret = tce_get_hva_cached(container, tbl->it_page_shift,
+					tce, &hva);
+		else
+			ret = tce_get_hva(container, tbl->it_page_shift,
+					tce, &hva);
 		if (ret)
 			break;
 
@@ -441,6 +660,50 @@ static long tce_iommu_ioctl(void *iommu_data,
 
 		return ret;
 	}
+	case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
+		struct vfio_iommu_spapr_register_memory param;
+
+		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_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;
+
+		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);
+		tce_unregister_pages(container, param.vaddr, param.size);
+		mutex_unlock(&container->lock);
+
+		return 0;
+	}
 	case VFIO_IOMMU_ENABLE:
 		mutex_lock(&container->lock);
 		ret = tce_iommu_enable(container);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 82889c3..b17e120 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -493,6 +493,31 @@ 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 */
-- 
2.0.0

[PATCH kernel v6 09/29] vfio: powerpc/spapr: Rework attach/detach

[Alexey Kardashevskiy]

This is to make extended ownership and multiple groups support patches
simpler for review.

This is a mechanical patch.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 38 ++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 838123e..353d2d5 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -744,16 +744,21 @@ static int tce_iommu_attach_group(void *iommu_data,
 				iommu_group_id(container->tbl->it_group),
 				iommu_group_id(iommu_group));
 		ret = -EBUSY;
-	} else if (container->enabled) {
+		goto unlock_exit;
+	}
+
+	if (container->enabled) {
 		pr_err("tce_vfio: attaching group #%u to enabled container\n",
 				iommu_group_id(iommu_group));
 		ret = -EBUSY;
-	} else {
-		ret = iommu_take_ownership(tbl);
-		if (!ret)
-			container->tbl = tbl;
+		goto unlock_exit;
 	}
 
+	ret = iommu_take_ownership(tbl);
+	if (!ret)
+		container->tbl = tbl;
+
+unlock_exit:
 	mutex_unlock(&container->lock);
 
 	return ret;
@@ -771,18 +776,21 @@ static void tce_iommu_detach_group(void *iommu_data,
 		pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
 				iommu_group_id(iommu_group),
 				iommu_group_id(tbl->it_group));
-	} else {
-		if (container->enabled) {
-			pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
-					iommu_group_id(tbl->it_group));
-			tce_iommu_disable(container);
-		}
+		goto unlock_exit;
+	}
 
-		/* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
-				iommu_group_id(iommu_group), iommu_group); */
-		container->tbl = NULL;
-		iommu_release_ownership(tbl);
+	if (container->enabled) {
+		pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
+				iommu_group_id(tbl->it_group));
+		tce_iommu_disable(container);
 	}
+
+	/* pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
+	   iommu_group_id(iommu_group), iommu_group); */
+	container->tbl = NULL;
+	iommu_release_ownership(tbl);
+
+unlock_exit:
 	mutex_unlock(&container->lock);
 }
 
-- 
2.0.0

[PATCH kernel v6 10/29] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE

[Alexey Kardashevskiy]

Normally a bitmap from the iommu_table is used to track what TCE entry
is in use. Since we are going to use iommu_table without its locks and
do xchg() instead, it becomes essential not to put bits which are not
implied in the direction flag.

This adds iommu_direction_to_tce_perm() (its counterpart is there already)
and uses it for powernv's pnv_tce_build().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h     |  1 +
 arch/powerpc/kernel/iommu.c          | 15 +++++++++++++++
 arch/powerpc/platforms/powernv/pci.c |  7 +------
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index ed69b7d..2af2d70 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -203,6 +203,7 @@ extern int iommu_take_ownership(struct iommu_table *tbl);
 extern void iommu_release_ownership(struct iommu_table *tbl);
 
 extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
+extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_IOMMU_H */
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 1b4a178..865beef 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -916,6 +916,21 @@ enum dma_data_direction iommu_tce_direction(unsigned long tce)
 }
 EXPORT_SYMBOL_GPL(iommu_tce_direction);
 
+unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+		return TCE_PCI_READ | TCE_PCI_WRITE;
+	case DMA_FROM_DEVICE:
+		return TCE_PCI_WRITE;
+	case DMA_TO_DEVICE:
+		return TCE_PCI_READ;
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm);
+
 void iommu_flush_tce(struct iommu_table *tbl)
 {
 	/* Flush/invalidate TLB caches if necessary */
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 54323d6..609f5b1 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -593,15 +593,10 @@ static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
 			 unsigned long uaddr, enum dma_data_direction direction,
 			 struct dma_attrs *attrs, bool rm)
 {
-	u64 proto_tce;
+	u64 proto_tce = iommu_direction_to_tce_perm(direction);
 	__be64 *tcep, *tces;
 	u64 rpn;
 
-	proto_tce = TCE_PCI_READ; // Read allowed
-
-	if (direction != DMA_TO_DEVICE)
-		proto_tce |= TCE_PCI_WRITE;
-
 	tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
 	rpn = __pa(uaddr) >> tbl->it_page_shift;
 
-- 
2.0.0

[PATCH kernel v6 11/29] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table

[Alexey Kardashevskiy]

This adds a iommu_table_ops struct and puts pointer to it into
the iommu_table struct. This moves tce_build/tce_free/tce_get/tce_flush
callbacks from ppc_md to the new struct where they really belong to.

This adds the requirement for @it_ops to be initialized before calling
iommu_init_table() to make sure that we do not leave any IOMMU table
with iommu_table_ops uninitialized. This is not a parameter of
iommu_init_table() though as there will be cases when iommu_init_table()
will not be called on TCE tables, for example - VFIO.

This does s/tce_build/set/, s/tce_free/clear/ and removes "tce_"
redundand prefixes.

This removes tce_xxx_rm handlers from ppc_md but does not add
them to iommu_table_ops as this will be done later if we decide to
support TCE hypercalls in real mode.

For pSeries, this always uses tce_buildmulti_pSeriesLP/
tce_buildmulti_pSeriesLP. This changes multi callback to fall back to
tce_build_pSeriesLP/tce_free_pSeriesLP if FW_FEATURE_MULTITCE is not
present. The reason for this is we still have to support "multitce=off"
boot parameter in disable_multitce() and we do not want to walk through
all IOMMU tables in the system and replace "multi" callbacks with single
ones.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h            | 17 +++++++++++
 arch/powerpc/include/asm/machdep.h          | 25 ----------------
 arch/powerpc/kernel/iommu.c                 | 46 +++++++++++++++--------------
 arch/powerpc/kernel/vio.c                   |  5 ++++
 arch/powerpc/platforms/cell/iommu.c         |  8 +++--
 arch/powerpc/platforms/pasemi/iommu.c       |  7 +++--
 arch/powerpc/platforms/powernv/pci-ioda.c   |  2 ++
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |  1 +
 arch/powerpc/platforms/powernv/pci.c        | 23 ++++-----------
 arch/powerpc/platforms/powernv/pci.h        |  1 +
 arch/powerpc/platforms/pseries/iommu.c      | 34 +++++++++++----------
 arch/powerpc/sysdev/dart_iommu.c            | 12 ++++----
 12 files changed, 93 insertions(+), 88 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 2af2d70..d909e2a 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -43,6 +43,22 @@
 extern int iommu_is_off;
 extern int iommu_force_on;
 
+struct iommu_table_ops {
+	int (*set)(struct iommu_table *tbl,
+			long index, long npages,
+			unsigned long uaddr,
+			enum dma_data_direction direction,
+			struct dma_attrs *attrs);
+	void (*clear)(struct iommu_table *tbl,
+			long index, long npages);
+	unsigned long (*get)(struct iommu_table *tbl, long index);
+	void (*flush)(struct iommu_table *tbl);
+};
+
+/* These are used by VIO */
+extern struct iommu_table_ops iommu_table_lpar_multi_ops;
+extern struct iommu_table_ops iommu_table_pseries_ops;
+
 /*
  * IOMAP_MAX_ORDER defines the largest contiguous block
  * of dma space we can get.  IOMAP_MAX_ORDER = 13
@@ -77,6 +93,7 @@ struct iommu_table {
 #ifdef CONFIG_IOMMU_API
 	struct iommu_group *it_group;
 #endif
+	struct iommu_table_ops *it_ops;
 	void (*set_bypass)(struct iommu_table *tbl, bool enable);
 };
 
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index c8175a3..2abe744 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -65,31 +65,6 @@ struct machdep_calls {
 	 * destroyed as well */
 	void		(*hpte_clear_all)(void);
 
-	int		(*tce_build)(struct iommu_table *tbl,
-				     long index,
-				     long npages,
-				     unsigned long uaddr,
-				     enum dma_data_direction direction,
-				     struct dma_attrs *attrs);
-	void		(*tce_free)(struct iommu_table *tbl,
-				    long index,
-				    long npages);
-	unsigned long	(*tce_get)(struct iommu_table *tbl,
-				    long index);
-	void		(*tce_flush)(struct iommu_table *tbl);
-
-	/* _rm versions are for real mode use only */
-	int		(*tce_build_rm)(struct iommu_table *tbl,
-				     long index,
-				     long npages,
-				     unsigned long uaddr,
-				     enum dma_data_direction direction,
-				     struct dma_attrs *attrs);
-	void		(*tce_free_rm)(struct iommu_table *tbl,
-				    long index,
-				    long npages);
-	void		(*tce_flush_rm)(struct iommu_table *tbl);
-
 	void __iomem *	(*ioremap)(phys_addr_t addr, unsigned long size,
 				   unsigned long flags, void *caller);
 	void		(*iounmap)(volatile void __iomem *token);
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 865beef..57cb615 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -322,11 +322,11 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
 	ret = entry << tbl->it_page_shift;	/* Set the return dma address */
 
 	/* Put the TCEs in the HW table */
-	build_fail = ppc_md.tce_build(tbl, entry, npages,
+	build_fail = tbl->it_ops->set(tbl, entry, npages,
 				      (unsigned long)page &
 				      IOMMU_PAGE_MASK(tbl), direction, attrs);
 
-	/* ppc_md.tce_build() only returns non-zero for transient errors.
+	/* tbl->it_ops->set() only returns non-zero for transient errors.
 	 * Clean up the table bitmap in this case and return
 	 * DMA_ERROR_CODE. For all other errors the functionality is
 	 * not altered.
@@ -337,8 +337,8 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
 	}
 
 	/* Flush/invalidate TLB caches if necessary */
-	if (ppc_md.tce_flush)
-		ppc_md.tce_flush(tbl);
+	if (tbl->it_ops->flush)
+		tbl->it_ops->flush(tbl);
 
 	/* Make sure updates are seen by hardware */
 	mb();
@@ -408,7 +408,7 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 	if (!iommu_free_check(tbl, dma_addr, npages))
 		return;
 
-	ppc_md.tce_free(tbl, entry, npages);
+	tbl->it_ops->clear(tbl, entry, npages);
 
 	spin_lock_irqsave(&(pool->lock), flags);
 	bitmap_clear(tbl->it_map, free_entry, npages);
@@ -424,8 +424,8 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 	 * not do an mb() here on purpose, it is not needed on any of
 	 * the current platforms.
 	 */
-	if (ppc_md.tce_flush)
-		ppc_md.tce_flush(tbl);
+	if (tbl->it_ops->flush)
+		tbl->it_ops->flush(tbl);
 }
 
 int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
@@ -495,7 +495,7 @@ int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 			    npages, entry, dma_addr);
 
 		/* Insert into HW table */
-		build_fail = ppc_md.tce_build(tbl, entry, npages,
+		build_fail = tbl->it_ops->set(tbl, entry, npages,
 					      vaddr & IOMMU_PAGE_MASK(tbl),
 					      direction, attrs);
 		if(unlikely(build_fail))
@@ -534,8 +534,8 @@ int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 	}
 
 	/* Flush/invalidate TLB caches if necessary */
-	if (ppc_md.tce_flush)
-		ppc_md.tce_flush(tbl);
+	if (tbl->it_ops->flush)
+		tbl->it_ops->flush(tbl);
 
 	DBG("mapped %d elements:\n", outcount);
 
@@ -600,8 +600,8 @@ void ppc_iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	 * do not do an mb() here, the affected platforms do not need it
 	 * when freeing.
 	 */
-	if (ppc_md.tce_flush)
-		ppc_md.tce_flush(tbl);
+	if (tbl->it_ops->flush)
+		tbl->it_ops->flush(tbl);
 }
 
 static void iommu_table_clear(struct iommu_table *tbl)
@@ -613,17 +613,17 @@ static void iommu_table_clear(struct iommu_table *tbl)
 	 */
 	if (!is_kdump_kernel() || is_fadump_active()) {
 		/* Clear the table in case firmware left allocations in it */
-		ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
+		tbl->it_ops->clear(tbl, tbl->it_offset, tbl->it_size);
 		return;
 	}
 
 #ifdef CONFIG_CRASH_DUMP
-	if (ppc_md.tce_get) {
+	if (tbl->it_ops->get) {
 		unsigned long index, tceval, tcecount = 0;
 
 		/* Reserve the existing mappings left by the first kernel. */
 		for (index = 0; index < tbl->it_size; index++) {
-			tceval = ppc_md.tce_get(tbl, index + tbl->it_offset);
+			tceval = tbl->it_ops->get(tbl, index + tbl->it_offset);
 			/*
 			 * Freed TCE entry contains 0x7fffffffffffffff on JS20
 			 */
@@ -657,6 +657,8 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 	unsigned int i;
 	struct iommu_pool *p;
 
+	BUG_ON(!tbl->it_ops);
+
 	/* number of bytes needed for the bitmap */
 	sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
 
@@ -934,8 +936,8 @@ EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm);
 void iommu_flush_tce(struct iommu_table *tbl)
 {
 	/* Flush/invalidate TLB caches if necessary */
-	if (ppc_md.tce_flush)
-		ppc_md.tce_flush(tbl);
+	if (tbl->it_ops->flush)
+		tbl->it_ops->flush(tbl);
 
 	/* Make sure updates are seen by hardware */
 	mb();
@@ -946,7 +948,7 @@ int iommu_tce_clear_param_check(struct iommu_table *tbl,
 		unsigned long ioba, unsigned long tce_value,
 		unsigned long npages)
 {
-	/* ppc_md.tce_free() does not support any value but 0 */
+	/* tbl->it_ops->clear() does not support any value but 0 */
 	if (tce_value)
 		return -EINVAL;
 
@@ -994,9 +996,9 @@ unsigned long iommu_clear_tce(struct iommu_table *tbl, unsigned long entry)
 
 	spin_lock(&(pool->lock));
 
-	oldtce = ppc_md.tce_get(tbl, entry);
+	oldtce = tbl->it_ops->get(tbl, entry);
 	if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ))
-		ppc_md.tce_free(tbl, entry, 1);
+		tbl->it_ops->clear(tbl, entry, 1);
 	else
 		oldtce = 0;
 
@@ -1019,10 +1021,10 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 
 	spin_lock(&(pool->lock));
 
-	oldtce = ppc_md.tce_get(tbl, entry);
+	oldtce = tbl->it_ops->get(tbl, entry);
 	/* Add new entry if it is not busy */
 	if (!(oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)))
-		ret = ppc_md.tce_build(tbl, entry, 1, hwaddr, direction, NULL);
+		ret = tbl->it_ops->set(tbl, entry, 1, hwaddr, direction, NULL);
 
 	spin_unlock(&(pool->lock));
 
diff --git a/arch/powerpc/kernel/vio.c b/arch/powerpc/kernel/vio.c
index 5bfdab9..b41426c 100644
--- a/arch/powerpc/kernel/vio.c
+++ b/arch/powerpc/kernel/vio.c
@@ -1196,6 +1196,11 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
 	tbl->it_type = TCE_VB;
 	tbl->it_blocksize = 16;
 
+	if (firmware_has_feature(FW_FEATURE_LPAR))
+		tbl->it_ops = &iommu_table_lpar_multi_ops;
+	else
+		tbl->it_ops = &iommu_table_pseries_ops;
+
 	return iommu_init_table(tbl, -1);
 }
 
diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index c7c8720..72763a8 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -465,6 +465,11 @@ static inline u32 cell_iommu_get_ioid(struct device_node *np)
 	return *ioid;
 }
 
+static struct iommu_table_ops cell_iommu_ops = {
+	.set = tce_build_cell,
+	.clear = tce_free_cell
+};
+
 static struct iommu_window * __init
 cell_iommu_setup_window(struct cbe_iommu *iommu, struct device_node *np,
 			unsigned long offset, unsigned long size,
@@ -491,6 +496,7 @@ cell_iommu_setup_window(struct cbe_iommu *iommu, struct device_node *np,
 	window->table.it_offset =
 		(offset >> window->table.it_page_shift) + pte_offset;
 	window->table.it_size = size >> window->table.it_page_shift;
+	window->table.it_ops = &cell_iommu_ops;
 
 	iommu_init_table(&window->table, iommu->nid);
 
@@ -1200,8 +1206,6 @@ static int __init cell_iommu_init(void)
 	/* Setup various ppc_md. callbacks */
 	ppc_md.pci_dma_dev_setup = cell_pci_dma_dev_setup;
 	ppc_md.dma_get_required_mask = cell_dma_get_required_mask;
-	ppc_md.tce_build = tce_build_cell;
-	ppc_md.tce_free = tce_free_cell;
 
 	if (!iommu_fixed_disabled && cell_iommu_fixed_mapping_init() == 0)
 		goto bail;
diff --git a/arch/powerpc/platforms/pasemi/iommu.c b/arch/powerpc/platforms/pasemi/iommu.c
index 2e576f2..b7245b2 100644
--- a/arch/powerpc/platforms/pasemi/iommu.c
+++ b/arch/powerpc/platforms/pasemi/iommu.c
@@ -132,6 +132,10 @@ static void iobmap_free(struct iommu_table *tbl, long index,
 	}
 }
 
+static struct iommu_table_ops iommu_table_iobmap_ops = {
+	.set = iobmap_build,
+	.clear  = iobmap_free
+};
 
 static void iommu_table_iobmap_setup(void)
 {
@@ -151,6 +155,7 @@ static void iommu_table_iobmap_setup(void)
 	 * Should probably be 8 (64 bytes)
 	 */
 	iommu_table_iobmap.it_blocksize = 4;
+	iommu_table_iobmap.it_ops = &iommu_table_iobmap_ops;
 	iommu_init_table(&iommu_table_iobmap, 0);
 	pr_debug(" <- %s\n", __func__);
 }
@@ -250,8 +255,6 @@ void __init iommu_init_early_pasemi(void)
 
 	ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pasemi;
 	ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pasemi;
-	ppc_md.tce_build = iobmap_build;
-	ppc_md.tce_free  = iobmap_free;
 	set_pci_dma_ops(&dma_iommu_ops);
 }
 
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 6c9ff2b..85e64a5 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1231,6 +1231,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 				 TCE_PCI_SWINV_FREE   |
 				 TCE_PCI_SWINV_PAIR);
 	}
+	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
 	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
 
@@ -1364,6 +1365,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				8);
 		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
 	}
+	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
 	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
 
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index 6ef6d4d..0256fcc 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -87,6 +87,7 @@ static void pnv_pci_p5ioc2_dma_dev_setup(struct pnv_phb *phb,
 					 struct pci_dev *pdev)
 {
 	if (phb->p5ioc2.iommu_table.it_map == NULL) {
+		phb->p5ioc2.iommu_table.it_ops = &pnv_iommu_ops;
 		iommu_init_table(&phb->p5ioc2.iommu_table, phb->hose->node);
 		iommu_register_group(&phb->p5ioc2.iommu_table,
 				pci_domain_nr(phb->hose->bus), phb->opal_id);
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 609f5b1..c619ec6 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -647,18 +647,11 @@ static unsigned long pnv_tce_get(struct iommu_table *tbl, long index)
 	return ((u64 *)tbl->it_base)[index - tbl->it_offset];
 }
 
-static int pnv_tce_build_rm(struct iommu_table *tbl, long index, long npages,
-			    unsigned long uaddr,
-			    enum dma_data_direction direction,
-			    struct dma_attrs *attrs)
-{
-	return pnv_tce_build(tbl, index, npages, uaddr, direction, attrs, true);
-}
-
-static void pnv_tce_free_rm(struct iommu_table *tbl, long index, long npages)
-{
-	pnv_tce_free(tbl, index, npages, true);
-}
+struct iommu_table_ops pnv_iommu_ops = {
+	.set = pnv_tce_build_vm,
+	.clear = pnv_tce_free_vm,
+	.get = pnv_tce_get,
+};
 
 void pnv_pci_setup_iommu_table(struct iommu_table *tbl,
 			       void *tce_mem, u64 tce_size,
@@ -692,6 +685,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
 		return NULL;
 	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
 				  be32_to_cpup(sizep), 0, IOMMU_PAGE_SHIFT_4K);
+	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, hose->node);
 	iommu_register_group(tbl, pci_domain_nr(hose->bus), 0);
 
@@ -817,11 +811,6 @@ void __init pnv_pci_init(void)
 
 	/* Configure IOMMU DMA hooks */
 	ppc_md.pci_dma_dev_setup = pnv_pci_dma_dev_setup;
-	ppc_md.tce_build = pnv_tce_build_vm;
-	ppc_md.tce_free = pnv_tce_free_vm;
-	ppc_md.tce_build_rm = pnv_tce_build_rm;
-	ppc_md.tce_free_rm = pnv_tce_free_rm;
-	ppc_md.tce_get = pnv_tce_get;
 	set_pci_dma_ops(&dma_iommu_ops);
 
 	/* Configure MSIs */
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 6c02ff8..f726700 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -216,6 +216,7 @@ extern struct pci_ops pnv_pci_ops;
 #ifdef CONFIG_EEH
 extern struct pnv_eeh_ops ioda_eeh_ops;
 #endif
+extern struct iommu_table_ops pnv_iommu_ops;
 
 void pnv_pci_dump_phb_diag_data(struct pci_controller *hose,
 				unsigned char *log_buff);
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 7803a19..48d1fde 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -192,7 +192,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 	int ret = 0;
 	unsigned long flags;
 
-	if (npages == 1) {
+	if ((npages == 1) || !firmware_has_feature(FW_FEATURE_MULTITCE)) {
 		return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
 		                           direction, attrs);
 	}
@@ -284,6 +284,9 @@ static void tce_freemulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long n
 {
 	u64 rc;
 
+	if (!firmware_has_feature(FW_FEATURE_MULTITCE))
+		return tce_free_pSeriesLP(tbl, tcenum, npages);
+
 	rc = plpar_tce_stuff((u64)tbl->it_index, (u64)tcenum << 12, 0, npages);
 
 	if (rc && printk_ratelimit()) {
@@ -459,7 +462,6 @@ static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn,
 	return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg);
 }
 
-
 #ifdef CONFIG_PCI
 static void iommu_table_setparms(struct pci_controller *phb,
 				 struct device_node *dn,
@@ -545,6 +547,12 @@ static void iommu_table_setparms_lpar(struct pci_controller *phb,
 	tbl->it_size = size >> tbl->it_page_shift;
 }
 
+struct iommu_table_ops iommu_table_pseries_ops = {
+	.set = tce_build_pSeries,
+	.clear = tce_free_pSeries,
+	.get = tce_get_pseries
+};
+
 static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 {
 	struct device_node *dn;
@@ -613,6 +621,7 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 			   pci->phb->node);
 
 	iommu_table_setparms(pci->phb, dn, tbl);
+	tbl->it_ops = &iommu_table_pseries_ops;
 	pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
 	iommu_register_group(tbl, pci_domain_nr(bus), 0);
 
@@ -624,6 +633,11 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 	pr_debug("ISA/IDE, window size is 0x%llx\n", pci->phb->dma_window_size);
 }
 
+struct iommu_table_ops iommu_table_lpar_multi_ops = {
+	.set = tce_buildmulti_pSeriesLP,
+	.clear = tce_freemulti_pSeriesLP,
+	.get = tce_get_pSeriesLP
+};
 
 static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
 {
@@ -658,6 +672,7 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   ppci->phb->node);
 		iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
+		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
 		iommu_register_group(tbl, pci_domain_nr(bus), 0);
 		pr_debug("  created table: %p\n", ppci->iommu_table);
@@ -685,6 +700,7 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   phb->node);
 		iommu_table_setparms(phb, dn, tbl);
+		tbl->it_ops = &iommu_table_pseries_ops;
 		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
 		iommu_register_group(tbl, pci_domain_nr(phb->bus), 0);
 		set_iommu_table_base_and_group(&dev->dev,
@@ -1107,6 +1123,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   pci->phb->node);
 		iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
+		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
 		iommu_register_group(tbl, pci_domain_nr(pci->phb->bus), 0);
 		pr_debug("  created table: %p\n", pci->iommu_table);
@@ -1299,22 +1316,11 @@ void iommu_init_early_pSeries(void)
 		return;
 
 	if (firmware_has_feature(FW_FEATURE_LPAR)) {
-		if (firmware_has_feature(FW_FEATURE_MULTITCE)) {
-			ppc_md.tce_build = tce_buildmulti_pSeriesLP;
-			ppc_md.tce_free	 = tce_freemulti_pSeriesLP;
-		} else {
-			ppc_md.tce_build = tce_build_pSeriesLP;
-			ppc_md.tce_free	 = tce_free_pSeriesLP;
-		}
-		ppc_md.tce_get   = tce_get_pSeriesLP;
 		ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pSeriesLP;
 		ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pSeriesLP;
 		ppc_md.dma_set_mask = dma_set_mask_pSeriesLP;
 		ppc_md.dma_get_required_mask = dma_get_required_mask_pSeriesLP;
 	} else {
-		ppc_md.tce_build = tce_build_pSeries;
-		ppc_md.tce_free  = tce_free_pSeries;
-		ppc_md.tce_get   = tce_get_pseries;
 		ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pSeries;
 		ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pSeries;
 	}
@@ -1332,8 +1338,6 @@ static int __init disable_multitce(char *str)
 	    firmware_has_feature(FW_FEATURE_LPAR) &&
 	    firmware_has_feature(FW_FEATURE_MULTITCE)) {
 		printk(KERN_INFO "Disabling MULTITCE firmware feature\n");
-		ppc_md.tce_build = tce_build_pSeriesLP;
-		ppc_md.tce_free	 = tce_free_pSeriesLP;
 		powerpc_firmware_features &= ~FW_FEATURE_MULTITCE;
 	}
 	return 1;
diff --git a/arch/powerpc/sysdev/dart_iommu.c b/arch/powerpc/sysdev/dart_iommu.c
index 9e5353f..ab361a3 100644
--- a/arch/powerpc/sysdev/dart_iommu.c
+++ b/arch/powerpc/sysdev/dart_iommu.c
@@ -286,6 +286,12 @@ static int __init dart_init(struct device_node *dart_node)
 	return 0;
 }
 
+static struct iommu_table_ops iommu_dart_ops = {
+	.set = dart_build,
+	.clear = dart_free,
+	.flush = dart_flush,
+};
+
 static void iommu_table_dart_setup(void)
 {
 	iommu_table_dart.it_busno = 0;
@@ -298,6 +304,7 @@ static void iommu_table_dart_setup(void)
 	iommu_table_dart.it_base = (unsigned long)dart_vbase;
 	iommu_table_dart.it_index = 0;
 	iommu_table_dart.it_blocksize = 1;
+	iommu_table_dart.it_ops = &iommu_dart_ops;
 	iommu_init_table(&iommu_table_dart, -1);
 
 	/* Reserve the last page of the DART to avoid possible prefetch
@@ -386,11 +393,6 @@ void __init iommu_init_early_dart(void)
 	if (dart_init(dn) != 0)
 		goto bail;
 
-	/* Setup low level TCE operations for the core IOMMU code */
-	ppc_md.tce_build = dart_build;
-	ppc_md.tce_free  = dart_free;
-	ppc_md.tce_flush = dart_flush;
-
 	/* Setup bypass if supported */
 	if (dart_is_u4)
 		ppc_md.dma_set_mask = dart_dma_set_mask;
-- 
2.0.0

[PATCH kernel v6 12/29] powerpc/iommu: Introduce iommu_table_alloc() helper

[Alexey Kardashevskiy]

This replaces multiple calls of kzalloc_node() with a new
iommu_table_alloc() helper. Right now it calls kzalloc_node() but
later it will be modified to allocate a iommu_table_group struct with
a single iommu_table in it.

Later the helper will allocate a iommu_table_group struct which embeds
the iommu table(s).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h       |  1 +
 arch/powerpc/kernel/iommu.c            |  9 +++++++++
 arch/powerpc/platforms/powernv/pci.c   |  2 +-
 arch/powerpc/platforms/pseries/iommu.c | 12 ++++--------
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index d909e2a..eb75726 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -117,6 +117,7 @@ static inline void *get_iommu_table_base(struct device *dev)
 	return dev->archdata.dma_data.iommu_table_base;
 }
 
+extern struct iommu_table *iommu_table_alloc(int node);
 /* Frees table for an individual device node */
 extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
 
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 57cb615..dbc5d8d 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -710,6 +710,15 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 	return tbl;
 }
 
+struct iommu_table *iommu_table_alloc(int node)
+{
+	struct iommu_table *tbl;
+
+	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
+
+	return tbl;
+}
+
 void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 {
 	unsigned long bitmap_sz;
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index c619ec6..1c31ac8 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -680,7 +680,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
 		       hose->dn->full_name);
 		return NULL;
 	}
-	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, hose->node);
+	tbl = iommu_table_alloc(hose->node);
 	if (WARN_ON(!tbl))
 		return NULL;
 	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 48d1fde..41a8b14 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -617,8 +617,7 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 	pci->phb->dma_window_size = 0x8000000ul;
 	pci->phb->dma_window_base_cur = 0x8000000ul;
 
-	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
-			   pci->phb->node);
+	tbl = iommu_table_alloc(pci->phb->node);
 
 	iommu_table_setparms(pci->phb, dn, tbl);
 	tbl->it_ops = &iommu_table_pseries_ops;
@@ -669,8 +668,7 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
 		 pdn->full_name, ppci->iommu_table);
 
 	if (!ppci->iommu_table) {
-		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
-				   ppci->phb->node);
+		tbl = iommu_table_alloc(ppci->phb->node);
 		iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
 		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
@@ -697,8 +695,7 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
 		struct pci_controller *phb = PCI_DN(dn)->phb;
 
 		pr_debug(" --> first child, no bridge. Allocating iommu table.\n");
-		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
-				   phb->node);
+		tbl = iommu_table_alloc(phb->node);
 		iommu_table_setparms(phb, dn, tbl);
 		tbl->it_ops = &iommu_table_pseries_ops;
 		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
@@ -1120,8 +1117,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 
 	pci = PCI_DN(pdn);
 	if (!pci->iommu_table) {
-		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
-				   pci->phb->node);
+		tbl = iommu_table_alloc(pci->phb->node);
 		iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
 		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
-- 
2.0.0

[PATCH kernel v6 13/29] powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group

[Alexey Kardashevskiy]

Modern IBM POWERPC systems support multiple (currently two) TCE tables
per IOMMU group (a.k.a. PE). This adds a iommu_table_group container
for TCE tables. Right now just one table is supported.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h            |  18 +++--
 arch/powerpc/kernel/iommu.c                 |  34 ++++----
 arch/powerpc/platforms/powernv/pci-ioda.c   |  38 +++++----
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |  17 ++--
 arch/powerpc/platforms/powernv/pci.c        |   2 +-
 arch/powerpc/platforms/powernv/pci.h        |   4 +-
 arch/powerpc/platforms/pseries/iommu.c      |   9 ++-
 drivers/vfio/vfio_iommu_spapr_tce.c         | 120 ++++++++++++++++++++--------
 8 files changed, 160 insertions(+), 82 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index eb75726..667aa1a 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -90,9 +90,7 @@ struct iommu_table {
 	struct iommu_pool pools[IOMMU_NR_POOLS];
 	unsigned long *it_map;       /* A simple allocation bitmap for now */
 	unsigned long  it_page_shift;/* table iommu page size */
-#ifdef CONFIG_IOMMU_API
-	struct iommu_group *it_group;
-#endif
+	struct iommu_table_group *it_group;
 	struct iommu_table_ops *it_ops;
 	void (*set_bypass)(struct iommu_table *tbl, bool enable);
 };
@@ -126,14 +124,24 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
  */
 extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
 					    int nid);
+
+#define IOMMU_TABLE_GROUP_MAX_TABLES	1
+
+struct iommu_table_group {
 #ifdef CONFIG_IOMMU_API
-extern void iommu_register_group(struct iommu_table *tbl,
+	struct iommu_group *group;
+#endif
+	struct iommu_table tables[IOMMU_TABLE_GROUP_MAX_TABLES];
+};
+
+#ifdef CONFIG_IOMMU_API
+extern void iommu_register_group(struct iommu_table_group *table_group,
 				 int pci_domain_number, unsigned long pe_num);
 extern int iommu_add_device(struct device *dev);
 extern void iommu_del_device(struct device *dev);
 extern int __init tce_iommu_bus_notifier_init(void);
 #else
-static inline void iommu_register_group(struct iommu_table *tbl,
+static inline void iommu_register_group(struct iommu_table_group *table_group,
 					int pci_domain_number,
 					unsigned long pe_num)
 {
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index dbc5d8d..7794dce 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -712,17 +712,20 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 
 struct iommu_table *iommu_table_alloc(int node)
 {
-	struct iommu_table *tbl;
+	struct iommu_table_group *table_group;
 
-	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
+	table_group = kzalloc_node(sizeof(struct iommu_table_group), GFP_KERNEL,
+			   node);
+	table_group->tables[0].it_group = table_group;
 
-	return tbl;
+	return &table_group->tables[0];
 }
 
 void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 {
 	unsigned long bitmap_sz;
 	unsigned int order;
+	struct iommu_table_group *table_group = tbl->it_group;
 
 	if (!tbl || !tbl->it_map) {
 		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
@@ -738,9 +741,9 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 		clear_bit(0, tbl->it_map);
 
 #ifdef CONFIG_IOMMU_API
-	if (tbl->it_group) {
-		iommu_group_put(tbl->it_group);
-		BUG_ON(tbl->it_group);
+	if (table_group->group) {
+		iommu_group_put(table_group->group);
+		BUG_ON(table_group->group);
 	}
 #endif
 
@@ -756,7 +759,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 	free_pages((unsigned long) tbl->it_map, order);
 
 	/* free table */
-	kfree(tbl);
+	kfree(table_group);
 }
 
 /* Creates TCEs for a user provided buffer.  The user buffer must be
@@ -888,11 +891,12 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size,
  */
 static void group_release(void *iommu_data)
 {
-	struct iommu_table *tbl = iommu_data;
-	tbl->it_group = NULL;
+	struct iommu_table_group *table_group = iommu_data;
+
+	table_group->group = NULL;
 }
 
-void iommu_register_group(struct iommu_table *tbl,
+void iommu_register_group(struct iommu_table_group *table_group,
 		int pci_domain_number, unsigned long pe_num)
 {
 	struct iommu_group *grp;
@@ -904,8 +908,8 @@ void iommu_register_group(struct iommu_table *tbl,
 				PTR_ERR(grp));
 		return;
 	}
-	tbl->it_group = grp;
-	iommu_group_set_iommudata(grp, tbl, group_release);
+	table_group->group = grp;
+	iommu_group_set_iommudata(grp, table_group, group_release);
 	name = kasprintf(GFP_KERNEL, "domain%d-pe%lx",
 			pci_domain_number, pe_num);
 	if (!name)
@@ -1108,7 +1112,7 @@ int iommu_add_device(struct device *dev)
 	}
 
 	tbl = get_iommu_table_base(dev);
-	if (!tbl || !tbl->it_group) {
+	if (!tbl || !tbl->it_group || !tbl->it_group->group) {
 		pr_debug("%s: Skipping device %s with no tbl\n",
 			 __func__, dev_name(dev));
 		return 0;
@@ -1116,7 +1120,7 @@ int iommu_add_device(struct device *dev)
 
 	pr_debug("%s: Adding %s to iommu group %d\n",
 		 __func__, dev_name(dev),
-		 iommu_group_id(tbl->it_group));
+		 iommu_group_id(tbl->it_group->group));
 
 	if (PAGE_SIZE < IOMMU_PAGE_SIZE(tbl)) {
 		pr_err("%s: Invalid IOMMU page size %lx (%lx) on %s\n",
@@ -1125,7 +1129,7 @@ int iommu_add_device(struct device *dev)
 		return -EINVAL;
 	}
 
-	return iommu_group_add_device(tbl->it_group, dev);
+	return iommu_group_add_device(tbl->it_group->group, dev);
 }
 EXPORT_SYMBOL_GPL(iommu_add_device);
 
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 85e64a5..a964c50 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -23,6 +23,7 @@
 #include <linux/io.h>
 #include <linux/msi.h>
 #include <linux/memblock.h>
+#include <linux/iommu.h>
 
 #include <asm/sections.h>
 #include <asm/io.h>
@@ -989,7 +990,7 @@ static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *pdev
 
 	pe = &phb->ioda.pe_array[pdn->pe_number];
 	WARN_ON(get_dma_ops(&pdev->dev) != &dma_iommu_ops);
-	set_iommu_table_base_and_group(&pdev->dev, &pe->tce32_table);
+	set_iommu_table_base_and_group(&pdev->dev, &pe->table_group.tables[0]);
 }
 
 static int pnv_pci_ioda_dma_set_mask(struct pnv_phb *phb,
@@ -1016,7 +1017,7 @@ static int pnv_pci_ioda_dma_set_mask(struct pnv_phb *phb,
 	} else {
 		dev_info(&pdev->dev, "Using 32-bit DMA via iommu\n");
 		set_dma_ops(&pdev->dev, &dma_iommu_ops);
-		set_iommu_table_base(&pdev->dev, &pe->tce32_table);
+		set_iommu_table_base(&pdev->dev, &pe->table_group.tables[0]);
 	}
 	*pdev->dev.dma_mask = dma_mask;
 	return 0;
@@ -1053,9 +1054,10 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe,
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		if (add_to_iommu_group)
 			set_iommu_table_base_and_group(&dev->dev,
-						       &pe->tce32_table);
+					&pe->table_group.tables[0]);
 		else
-			set_iommu_table_base(&dev->dev, &pe->tce32_table);
+			set_iommu_table_base(&dev->dev,
+					&pe->table_group.tables[0]);
 
 		if (dev->subordinate)
 			pnv_ioda_setup_bus_dma(pe, dev->subordinate,
@@ -1145,8 +1147,8 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
 void pnv_pci_ioda_tce_invalidate(struct iommu_table *tbl,
 				 __be64 *startp, __be64 *endp, bool rm)
 {
-	struct pnv_ioda_pe *pe = container_of(tbl, struct pnv_ioda_pe,
-					      tce32_table);
+	struct pnv_ioda_pe *pe = container_of(tbl->it_group, struct pnv_ioda_pe,
+					      table_group);
 	struct pnv_phb *phb = pe->phb;
 
 	if (phb->type == PNV_PHB_IODA1)
@@ -1211,8 +1213,11 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 		}
 	}
 
+	/* Setup iommu */
+	pe->table_group.tables[0].it_group = &pe->table_group;
+
 	/* Setup linux iommu table */
-	tbl = &pe->tce32_table;
+	tbl = &pe->table_group.tables[0];
 	pnv_pci_setup_iommu_table(tbl, addr, TCE32_TABLE_SIZE * segs,
 				  base << 28, IOMMU_PAGE_SHIFT_4K);
 
@@ -1233,7 +1238,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 	}
 	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
-	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
+	iommu_register_group(&pe->table_group, phb->hose->global_number,
+			pe->pe_number);
 
 	if (pe->pdev)
 		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);
@@ -1251,8 +1257,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 
 static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
 {
-	struct pnv_ioda_pe *pe = container_of(tbl, struct pnv_ioda_pe,
-					      tce32_table);
+	struct pnv_ioda_pe *pe = container_of(tbl->it_group, struct pnv_ioda_pe,
+					      table_group);
 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
 	int64_t rc;
 
@@ -1297,10 +1303,10 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb,
 	pe->tce_bypass_base = 1ull << 59;
 
 	/* Install set_bypass callback for VFIO */
-	pe->tce32_table.set_bypass = pnv_pci_ioda2_set_bypass;
+	pe->table_group.tables[0].set_bypass = pnv_pci_ioda2_set_bypass;
 
 	/* Enable bypass by default */
-	pnv_pci_ioda2_set_bypass(&pe->tce32_table, true);
+	pnv_pci_ioda2_set_bypass(&pe->table_group.tables[0], true);
 }
 
 static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
@@ -1347,8 +1353,11 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 		goto fail;
 	}
 
+	/* Setup iommu */
+	pe->table_group.tables[0].it_group = &pe->table_group;
+
 	/* Setup linux iommu table */
-	tbl = &pe->tce32_table;
+	tbl = &pe->table_group.tables[0];
 	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
 			IOMMU_PAGE_SHIFT_4K);
 
@@ -1367,7 +1376,8 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	}
 	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
-	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
+	iommu_register_group(&pe->table_group, phb->hose->global_number,
+			pe->pe_number);
 
 	if (pe->pdev)
 		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index 0256fcc..ff68cac 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -86,14 +86,16 @@ static void pnv_pci_init_p5ioc2_msis(struct pnv_phb *phb) { }
 static void pnv_pci_p5ioc2_dma_dev_setup(struct pnv_phb *phb,
 					 struct pci_dev *pdev)
 {
-	if (phb->p5ioc2.iommu_table.it_map == NULL) {
-		phb->p5ioc2.iommu_table.it_ops = &pnv_iommu_ops;
-		iommu_init_table(&phb->p5ioc2.iommu_table, phb->hose->node);
-		iommu_register_group(&phb->p5ioc2.iommu_table,
+	if (phb->p5ioc2.table_group.tables[0].it_map == NULL) {
+		phb->p5ioc2.table_group.tables[0].it_ops = &pnv_iommu_ops;
+		iommu_init_table(&phb->p5ioc2.table_group.tables[0],
+				phb->hose->node);
+		iommu_register_group(&phb->p5ioc2.table_group,
 				pci_domain_nr(phb->hose->bus), phb->opal_id);
 	}
 
-	set_iommu_table_base_and_group(&pdev->dev, &phb->p5ioc2.iommu_table);
+	set_iommu_table_base_and_group(&pdev->dev,
+			&phb->p5ioc2.table_group.tables[0]);
 }
 
 static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np, u64 hub_id,
@@ -167,9 +169,12 @@ static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np, u64 hub_id,
 	/* Setup MSI support */
 	pnv_pci_init_p5ioc2_msis(phb);
 
+	/* Setup iommu */
+	phb->p5ioc2.table_group.tables[0].it_group = &phb->p5ioc2.table_group;
+
 	/* Setup TCEs */
 	phb->dma_dev_setup = pnv_pci_p5ioc2_dma_dev_setup;
-	pnv_pci_setup_iommu_table(&phb->p5ioc2.iommu_table,
+	pnv_pci_setup_iommu_table(&phb->p5ioc2.table_group.tables[0],
 				  tce_mem, tce_size, 0,
 				  IOMMU_PAGE_SHIFT_4K);
 }
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 1c31ac8..3050cc8 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -687,7 +687,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
 				  be32_to_cpup(sizep), 0, IOMMU_PAGE_SHIFT_4K);
 	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, hose->node);
-	iommu_register_group(tbl, pci_domain_nr(hose->bus), 0);
+	iommu_register_group(tbl->it_group, pci_domain_nr(hose->bus), 0);
 
 	/* Deal with SW invalidated TCEs when needed (BML way) */
 	swinvp = of_get_property(hose->dn, "linux,tce-sw-invalidate-info",
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index f726700..762d906 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -53,7 +53,7 @@ struct pnv_ioda_pe {
 	/* "Base" iommu table, ie, 4K TCEs, 32-bit DMA */
 	int			tce32_seg;
 	int			tce32_segcount;
-	struct iommu_table	tce32_table;
+	struct iommu_table_group table_group;
 	phys_addr_t		tce_inval_reg_phys;
 
 	/* 64-bit TCE bypass region */
@@ -138,7 +138,7 @@ struct pnv_phb {
 
 	union {
 		struct {
-			struct iommu_table iommu_table;
+			struct iommu_table_group table_group;
 		} p5ioc2;
 
 		struct {
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 41a8b14..75ea581 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -622,7 +622,7 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 	iommu_table_setparms(pci->phb, dn, tbl);
 	tbl->it_ops = &iommu_table_pseries_ops;
 	pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
-	iommu_register_group(tbl, pci_domain_nr(bus), 0);
+	iommu_register_group(tbl->it_group, pci_domain_nr(bus), 0);
 
 	/* Divide the rest (1.75GB) among the children */
 	pci->phb->dma_window_size = 0x80000000ul;
@@ -672,7 +672,7 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
 		iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
 		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
-		iommu_register_group(tbl, pci_domain_nr(bus), 0);
+		iommu_register_group(tbl->it_group, pci_domain_nr(bus), 0);
 		pr_debug("  created table: %p\n", ppci->iommu_table);
 	}
 }
@@ -699,7 +699,7 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
 		iommu_table_setparms(phb, dn, tbl);
 		tbl->it_ops = &iommu_table_pseries_ops;
 		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
-		iommu_register_group(tbl, pci_domain_nr(phb->bus), 0);
+		iommu_register_group(tbl->it_group, pci_domain_nr(phb->bus), 0);
 		set_iommu_table_base_and_group(&dev->dev,
 					       PCI_DN(dn)->iommu_table);
 		return;
@@ -1121,7 +1121,8 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 		iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
 		tbl->it_ops = &iommu_table_lpar_multi_ops;
 		pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
-		iommu_register_group(tbl, pci_domain_nr(pci->phb->bus), 0);
+		iommu_register_group(tbl->it_group,
+				pci_domain_nr(pci->phb->bus), 0);
 		pr_debug("  created table: %p\n", pci->iommu_table);
 	} else {
 		pr_debug("  found DMA window, table: %p\n", pci->iommu_table);
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 353d2d5..bfbe8bb 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -91,7 +91,7 @@ static void decrement_locked_vm(long npages)
  */
 struct tce_container {
 	struct mutex lock;
-	struct iommu_table *tbl;
+	struct iommu_group *grp;
 	bool enabled;
 	unsigned long locked_pages;
 	struct list_head mem_list;
@@ -294,13 +294,41 @@ static bool tce_page_is_contained(struct page *page, unsigned page_shift)
 	return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift;
 }
 
+static struct iommu_table *spapr_tce_find_table(
+		struct tce_container *container,
+		phys_addr_t ioba)
+{
+	long i;
+	struct iommu_table *ret = NULL;
+	struct iommu_table_group *table_group;
+
+	table_group = iommu_group_get_iommudata(container->grp);
+	if (!table_group)
+		return NULL;
+
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = &table_group->tables[i];
+		unsigned long entry = ioba >> tbl->it_page_shift;
+		unsigned long start = tbl->it_offset;
+		unsigned long end = start + tbl->it_size;
+
+		if ((start <= entry) && (entry < end)) {
+			ret = tbl;
+			break;
+		}
+	}
+
+	return ret;
+}
+
 static int tce_iommu_enable(struct tce_container *container)
 {
 	int ret = 0;
 	unsigned long locked;
-	struct iommu_table *tbl = container->tbl;
+	struct iommu_table *tbl;
+	struct iommu_table_group *table_group;
 
-	if (!container->tbl)
+	if (!container->grp)
 		return -ENXIO;
 
 	if (!current->mm)
@@ -335,6 +363,11 @@ static int tce_iommu_enable(struct tce_container *container)
 	 * KVM agnostic.
 	 */
 	if (!tce_preregistered(container)) {
+		table_group = iommu_group_get_iommudata(container->grp);
+		if (!table_group)
+			return -ENODEV;
+
+		tbl = &table_group->tables[0];
 		locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
 		ret = try_increment_locked_vm(locked);
 		if (ret)
@@ -387,15 +420,17 @@ static int tce_iommu_clear(struct tce_container *container,
 static void tce_iommu_release(void *iommu_data)
 {
 	struct tce_container *container = iommu_data;
-	struct iommu_table *tbl = container->tbl;
+	struct iommu_table *tbl;
+	struct iommu_table_group *table_group;
 
-	WARN_ON(tbl && !tbl->it_group);
+	WARN_ON(container->grp);
 
-	if (tbl) {
+	if (container->grp) {
+		table_group = iommu_group_get_iommudata(container->grp);
+		tbl = &table_group->tables[0];
 		tce_iommu_clear(container, tbl,	tbl->it_offset, tbl->it_size);
 
-		if (tbl->it_group)
-			tce_iommu_detach_group(iommu_data, tbl->it_group);
+		tce_iommu_detach_group(iommu_data, container->grp);
 	}
 
 	tce_mem_unregister_all(container);
@@ -551,9 +586,16 @@ static long tce_iommu_ioctl(void *iommu_data,
 
 	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
 		struct vfio_iommu_spapr_tce_info info;
-		struct iommu_table *tbl = container->tbl;
+		struct iommu_table *tbl;
+		struct iommu_table_group *table_group;
 
-		if (WARN_ON(!tbl))
+		if (WARN_ON(!container->grp))
+			return -ENXIO;
+
+		table_group = iommu_group_get_iommudata(container->grp);
+
+		tbl = &table_group->tables[0];
+		if (WARN_ON_ONCE(!tbl))
 			return -ENXIO;
 
 		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
@@ -576,17 +618,12 @@ static long tce_iommu_ioctl(void *iommu_data,
 	}
 	case VFIO_IOMMU_MAP_DMA: {
 		struct vfio_iommu_type1_dma_map param;
-		struct iommu_table *tbl = container->tbl;
+		struct iommu_table *tbl;
 		unsigned long tce;
 
 		if (!container->enabled)
 			return -EPERM;
 
-		if (!tbl)
-			return -ENXIO;
-
-		BUG_ON(!tbl->it_group);
-
 		minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
 
 		if (copy_from_user(&param, (void __user *)arg, minsz))
@@ -599,6 +636,10 @@ static long tce_iommu_ioctl(void *iommu_data,
 				VFIO_DMA_MAP_FLAG_WRITE))
 			return -EINVAL;
 
+		tbl = spapr_tce_find_table(container, param.iova);
+		if (!tbl)
+			return -ENXIO;
+
 		if ((param.size & ~IOMMU_PAGE_MASK(tbl)) ||
 				(param.vaddr & ~IOMMU_PAGE_MASK(tbl)))
 			return -EINVAL;
@@ -624,14 +665,11 @@ static long tce_iommu_ioctl(void *iommu_data,
 	}
 	case VFIO_IOMMU_UNMAP_DMA: {
 		struct vfio_iommu_type1_dma_unmap param;
-		struct iommu_table *tbl = container->tbl;
+		struct iommu_table *tbl;
 
 		if (!container->enabled)
 			return -EPERM;
 
-		if (WARN_ON(!tbl))
-			return -ENXIO;
-
 		minsz = offsetofend(struct vfio_iommu_type1_dma_unmap,
 				size);
 
@@ -645,6 +683,10 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (param.flags)
 			return -EINVAL;
 
+		tbl = spapr_tce_find_table(container, param.iova);
+		if (!tbl)
+			return -ENXIO;
+
 		if (param.size & ~IOMMU_PAGE_MASK(tbl))
 			return -EINVAL;
 
@@ -717,10 +759,10 @@ static long tce_iommu_ioctl(void *iommu_data,
 		mutex_unlock(&container->lock);
 		return 0;
 	case VFIO_EEH_PE_OP:
-		if (!container->tbl || !container->tbl->it_group)
+		if (!container->grp)
 			return -ENODEV;
 
-		return vfio_spapr_iommu_eeh_ioctl(container->tbl->it_group,
+		return vfio_spapr_iommu_eeh_ioctl(container->grp,
 						  cmd, arg);
 	}
 
@@ -732,16 +774,15 @@ static int tce_iommu_attach_group(void *iommu_data,
 {
 	int ret;
 	struct tce_container *container = iommu_data;
-	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
+	struct iommu_table_group *table_group;
 
-	BUG_ON(!tbl);
 	mutex_lock(&container->lock);
 
 	/* pr_debug("tce_vfio: Attaching group #%u to iommu %p\n",
 			iommu_group_id(iommu_group), iommu_group); */
-	if (container->tbl) {
+	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->tbl->it_group),
+				iommu_group_id(container->grp),
 				iommu_group_id(iommu_group));
 		ret = -EBUSY;
 		goto unlock_exit;
@@ -754,9 +795,15 @@ static int tce_iommu_attach_group(void *iommu_data,
 		goto unlock_exit;
 	}
 
-	ret = iommu_take_ownership(tbl);
+	table_group = iommu_group_get_iommudata(iommu_group);
+	if (!table_group) {
+		ret = -ENXIO;
+		goto unlock_exit;
+	}
+
+	ret = iommu_take_ownership(&table_group->tables[0]);
 	if (!ret)
-		container->tbl = tbl;
+		container->grp = iommu_group;
 
 unlock_exit:
 	mutex_unlock(&container->lock);
@@ -768,27 +815,30 @@ static void tce_iommu_detach_group(void *iommu_data,
 		struct iommu_group *iommu_group)
 {
 	struct tce_container *container = iommu_data;
-	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
+	struct iommu_table_group *table_group;
 
-	BUG_ON(!tbl);
 	mutex_lock(&container->lock);
-	if (tbl != container->tbl) {
+	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(tbl->it_group));
+				iommu_group_id(container->grp));
 		goto unlock_exit;
 	}
 
 	if (container->enabled) {
 		pr_warn("tce_vfio: detaching group #%u from enabled container, forcing disable\n",
-				iommu_group_id(tbl->it_group));
+				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->tbl = NULL;
-	iommu_release_ownership(tbl);
+	container->grp = NULL;
+
+	table_group = iommu_group_get_iommudata(iommu_group);
+	BUG_ON(!table_group);
+
+	iommu_release_ownership(&table_group->tables[0]);
 
 unlock_exit:
 	mutex_unlock(&container->lock);
-- 
2.0.0

[PATCH kernel v6 14/29] vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control

[Alexey Kardashevskiy]

This replaces iommu_take_ownership()/iommu_release_ownership() calls
with the callback calls and it is up to the platform code to call
iommu_take_ownership()/iommu_release_ownership() if needed.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h    |  4 +--
 arch/powerpc/kernel/iommu.c         | 50 ++++++++++++++++++++++++++++---------
 drivers/vfio/vfio_iommu_spapr_tce.c |  4 +--
 3 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 667aa1a..b9e50d3 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -225,8 +225,8 @@ extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
 		unsigned long entry);
 
 extern void iommu_flush_tce(struct iommu_table *tbl);
-extern int iommu_take_ownership(struct iommu_table *tbl);
-extern void iommu_release_ownership(struct iommu_table *tbl);
+extern int iommu_take_ownership(struct iommu_table_group *table_group);
+extern void iommu_release_ownership(struct iommu_table_group *table_group);
 
 extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
 extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 7794dce..8358631 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1050,7 +1050,7 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 }
 EXPORT_SYMBOL_GPL(iommu_tce_build);
 
-int iommu_take_ownership(struct iommu_table *tbl)
+static int iommu_table_take_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
 
@@ -1064,19 +1064,36 @@ int iommu_take_ownership(struct iommu_table *tbl)
 
 	memset(tbl->it_map, 0xff, sz);
 
-	/*
-	 * Disable iommu bypass, otherwise the user can DMA to all of
-	 * our physical memory via the bypass window instead of just
-	 * the pages that has been explicitly mapped into the iommu
-	 */
-	if (tbl->set_bypass)
-		tbl->set_bypass(tbl, false);
+	return 0;
+}
+
+static void iommu_table_release_ownership(struct iommu_table *tbl);
+
+int iommu_take_ownership(struct iommu_table_group *table_group)
+{
+	int i, j, rc = 0;
+
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = &table_group->tables[i];
+
+		if (!tbl->it_map)
+			continue;
+
+		rc = iommu_table_take_ownership(tbl);
+		if (rc) {
+			for (j = 0; j < i; ++j)
+				iommu_table_release_ownership(
+						&table_group->tables[j]);
+
+			return rc;
+		}
+	}
 
 	return 0;
 }
 EXPORT_SYMBOL_GPL(iommu_take_ownership);
 
-void iommu_release_ownership(struct iommu_table *tbl)
+static void iommu_table_release_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
 
@@ -1086,9 +1103,18 @@ void iommu_release_ownership(struct iommu_table *tbl)
 	if (tbl->it_offset == 0)
 		set_bit(0, tbl->it_map);
 
-	/* The kernel owns the device now, we can restore the iommu bypass */
-	if (tbl->set_bypass)
-		tbl->set_bypass(tbl, true);
+}
+
+extern void iommu_release_ownership(struct iommu_table_group *table_group)
+{
+	int i;
+
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = &table_group->tables[i];
+
+		if (tbl->it_map)
+			iommu_table_release_ownership(tbl);
+	}
 }
 EXPORT_SYMBOL_GPL(iommu_release_ownership);
 
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index bfbe8bb..5d1762b 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -801,7 +801,7 @@ static int tce_iommu_attach_group(void *iommu_data,
 		goto unlock_exit;
 	}
 
-	ret = iommu_take_ownership(&table_group->tables[0]);
+	ret = iommu_take_ownership(table_group);
 	if (!ret)
 		container->grp = iommu_group;
 
@@ -838,7 +838,7 @@ static void tce_iommu_detach_group(void *iommu_data,
 	table_group = iommu_group_get_iommudata(iommu_group);
 	BUG_ON(!table_group);
 
-	iommu_release_ownership(&table_group->tables[0]);
+	iommu_release_ownership(table_group);
 
 unlock_exit:
 	mutex_unlock(&container->lock);
-- 
2.0.0

[PATCH kernel v6 15/29] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework IOMMU ownership control

[Alexey Kardashevskiy]

At the moment the iommu_table struct has a set_bypass() which enables/
disables DMA bypass on IODA2 PHB. This is exposed to POWERPC IOMMU code
which calls this callback when external IOMMU users such as VFIO are
about to get over a PHB.

The set_bypass() callback is not really an iommu_table function but
IOMMU/PE function. This introduces a iommu_table_group_ops struct and
adds a set_ownership() callback to it which is called when an external
user takes control over the IOMMU.

This renames set_bypass() to set_ownership() as it is not necessarily
just enabling bypassing, it can be something else/more so let's give it
more generic name. The bool parameter is inverted.

The callback is implemented for IODA2 only. Other platforms (P5IOC2,
IODA1) will use the old iommu_take_ownership/iommu_release_ownership API.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h          | 14 +++++++++++++-
 arch/powerpc/platforms/powernv/pci-ioda.c | 30 ++++++++++++++++++++++--------
 drivers/vfio/vfio_iommu_spapr_tce.c       | 26 ++++++++++++++++++++++----
 3 files changed, 57 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index b9e50d3..d1f8c6c 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -92,7 +92,6 @@ struct iommu_table {
 	unsigned long  it_page_shift;/* table iommu page size */
 	struct iommu_table_group *it_group;
 	struct iommu_table_ops *it_ops;
-	void (*set_bypass)(struct iommu_table *tbl, bool enable);
 };
 
 /* Pure 2^n version of get_order */
@@ -127,11 +126,24 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
 
 #define IOMMU_TABLE_GROUP_MAX_TABLES	1
 
+struct iommu_table_group;
+
+struct iommu_table_group_ops {
+	/*
+	 * Switches ownership from the kernel itself to an external
+	 * user. While onwership is enabled, the kernel cannot use IOMMU
+	 * for itself.
+	 */
+	void (*set_ownership)(struct iommu_table_group *table_group,
+			bool enable);
+};
+
 struct iommu_table_group {
 #ifdef CONFIG_IOMMU_API
 	struct iommu_group *group;
 #endif
 	struct iommu_table tables[IOMMU_TABLE_GROUP_MAX_TABLES];
+	struct iommu_table_group_ops *ops;
 };
 
 #ifdef CONFIG_IOMMU_API
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index a964c50..9687731 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1255,10 +1255,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 		__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
 }
 
-static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
+static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
 {
-	struct pnv_ioda_pe *pe = container_of(tbl->it_group, struct pnv_ioda_pe,
-					      table_group);
 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
 	int64_t rc;
 
@@ -1286,7 +1284,8 @@ static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable)
 		 * host side.
 		 */
 		if (pe->pdev)
-			set_iommu_table_base(&pe->pdev->dev, tbl);
+			set_iommu_table_base(&pe->pdev->dev,
+					&pe->table_group.tables[0]);
 		else
 			pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
 	}
@@ -1302,13 +1301,27 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb,
 	/* TVE #1 is selected by PCI address bit 59 */
 	pe->tce_bypass_base = 1ull << 59;
 
-	/* Install set_bypass callback for VFIO */
-	pe->table_group.tables[0].set_bypass = pnv_pci_ioda2_set_bypass;
-
 	/* Enable bypass by default */
-	pnv_pci_ioda2_set_bypass(&pe->table_group.tables[0], true);
+	pnv_pci_ioda2_set_bypass(pe, true);
 }
 
+static void pnv_ioda2_set_ownership(struct iommu_table_group *table_group,
+				     bool enable)
+{
+	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
+						table_group);
+	if (enable)
+		iommu_take_ownership(table_group);
+	else
+		iommu_release_ownership(table_group);
+
+	pnv_pci_ioda2_set_bypass(pe, !enable);
+}
+
+static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
+	.set_ownership = pnv_ioda2_set_ownership,
+};
+
 static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				       struct pnv_ioda_pe *pe)
 {
@@ -1376,6 +1389,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	}
 	tbl->it_ops = &pnv_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
+	pe->table_group.ops = &pnv_pci_ioda2_ops;
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
 			pe->pe_number);
 
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 5d1762b..7f62e92 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -801,9 +801,22 @@ static int tce_iommu_attach_group(void *iommu_data,
 		goto unlock_exit;
 	}
 
-	ret = iommu_take_ownership(table_group);
-	if (!ret)
-		container->grp = iommu_group;
+	if (!table_group->ops || !table_group->ops->set_ownership) {
+		ret = iommu_take_ownership(table_group);
+	} else {
+		/*
+		 * Disable iommu bypass, otherwise the user can DMA to all of
+		 * our physical memory via the bypass window instead of just
+		 * the pages that has been explicitly mapped into the iommu
+		 */
+		table_group->ops->set_ownership(table_group, true);
+		ret = 0;
+	}
+
+	if (ret)
+		goto unlock_exit;
+
+	container->grp = iommu_group;
 
 unlock_exit:
 	mutex_unlock(&container->lock);
@@ -838,9 +851,14 @@ static void tce_iommu_detach_group(void *iommu_data,
 	table_group = iommu_group_get_iommudata(iommu_group);
 	BUG_ON(!table_group);
 
-	iommu_release_ownership(table_group);
+	/* Kernel owns the device now, we can restore bypass */
+	if (!table_group->ops || !table_group->ops->set_ownership)
+		iommu_release_ownership(table_group);
+	else
+		table_group->ops->set_ownership(table_group, false);
 
 unlock_exit:
+
 	mutex_unlock(&container->lock);
 }
 
-- 
2.0.0

[PATCH kernel v6 16/29] powerpc/iommu: Fix IOMMU ownership control functions

[Alexey Kardashevskiy]

This adds missing locks in iommu_take_ownership()/
iommu_release_ownership().

This marks all pages busy in iommu_table::it_map in order to catch
errors if there is an attempt to use this table while ownership over it
is taken.

This only clears TCE content if there is no page marked busy in it_map.
Clearing must be done outside of the table locks as iommu_clear_tce()
called from iommu_clear_tces_and_put_pages() does this.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v5:
* do not store bit#0 value, it has to be set for zero-based table
anyway
* removed test_and_clear_bit
---
 arch/powerpc/kernel/iommu.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 8358631..df888a7 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -1052,17 +1052,28 @@ EXPORT_SYMBOL_GPL(iommu_tce_build);
 
 static int iommu_table_take_ownership(struct iommu_table *tbl)
 {
-	unsigned long sz = (tbl->it_size + 7) >> 3;
+	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
+	int ret = 0;
+
+	spin_lock_irqsave(&tbl->large_pool.lock, flags);
+	for (i = 0; i < tbl->nr_pools; i++)
+		spin_lock(&tbl->pools[i].lock);
 
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
 
 	if (!bitmap_empty(tbl->it_map, tbl->it_size)) {
 		pr_err("iommu_tce: it_map is not empty");
-		return -EBUSY;
+		ret = -EBUSY;
+		if (tbl->it_offset == 0)
+			set_bit(0, tbl->it_map);
+	} else {
+		memset(tbl->it_map, 0xff, sz);
 	}
 
-	memset(tbl->it_map, 0xff, sz);
+	for (i = 0; i < tbl->nr_pools; i++)
+		spin_unlock(&tbl->pools[i].lock);
+	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
 
 	return 0;
 }
@@ -1095,7 +1106,11 @@ EXPORT_SYMBOL_GPL(iommu_take_ownership);
 
 static void iommu_table_release_ownership(struct iommu_table *tbl)
 {
-	unsigned long sz = (tbl->it_size + 7) >> 3;
+	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
+
+	spin_lock_irqsave(&tbl->large_pool.lock, flags);
+	for (i = 0; i < tbl->nr_pools; i++)
+		spin_lock(&tbl->pools[i].lock);
 
 	memset(tbl->it_map, 0, sz);
 
@@ -1103,6 +1118,9 @@ static void iommu_table_release_ownership(struct iommu_table *tbl)
 	if (tbl->it_offset == 0)
 		set_bit(0, tbl->it_map);
 
+	for (i = 0; i < tbl->nr_pools; i++)
+		spin_unlock(&tbl->pools[i].lock);
+	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
 }
 
 extern void iommu_release_ownership(struct iommu_table_group *table_group)
-- 
2.0.0

[PATCH kernel v6 17/29] powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free()

[Alexey Kardashevskiy]

The pnv_pci_ioda_tce_invalidate() helper invalidates TCE cache. It is
supposed to be called on IODA1/2 and not called on p5ioc2. It receives
start and end host addresses of TCE table. This approach makes it possible
to get pnv_pci_ioda_tce_invalidate() unintentionally called on p5ioc2.
Another issue is that IODA2 needs PCI addresses to invalidate the cache
and those can be calculated from host addresses but since we are going
to implement multi-level TCE tables, calculating PCI address from
a host address might get either tricky or ugly as TCE table remains flat
on PCI bus but not in RAM.

This defines separate iommu_table_ops callbacks for p5ioc2 and IODA1/2
PHBs. They all call common pnv_tce_build/pnv_tce_free/pnv_tce_get helpers
but call PHB specific TCE invalidation helper (when needed).

This changes pnv_pci_ioda2_tce_invalidate() to receives TCE index and
number of pages which are PCI addresses shifted by IOMMU page shift.

The patch is pretty mechanical and behaviour is not expected to change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c   | 92 ++++++++++++++++++++++-------
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |  9 ++-
 arch/powerpc/platforms/powernv/pci.c        | 76 +++++++++---------------
 arch/powerpc/platforms/powernv/pci.h        |  7 ++-
 4 files changed, 111 insertions(+), 73 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 9687731..fd993bc 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1065,18 +1065,20 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe,
 	}
 }
 
-static void pnv_pci_ioda1_tce_invalidate(struct pnv_ioda_pe *pe,
-					 struct iommu_table *tbl,
-					 __be64 *startp, __be64 *endp, bool rm)
+static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
+		unsigned long index, unsigned long npages, bool rm)
 {
+	struct pnv_ioda_pe *pe = container_of(tbl->it_group,
+			struct pnv_ioda_pe, table_group);
 	__be64 __iomem *invalidate = rm ?
 		(__be64 __iomem *)pe->tce_inval_reg_phys :
 		(__be64 __iomem *)tbl->it_index;
 	unsigned long start, end, inc;
 	const unsigned shift = tbl->it_page_shift;
 
-	start = __pa(startp);
-	end = __pa(endp);
+	start = __pa((__be64 *)tbl->it_base + index - tbl->it_offset);
+	end = __pa((__be64 *)tbl->it_base + index - tbl->it_offset +
+			npages - 1);
 
 	/* BML uses this case for p6/p7/galaxy2: Shift addr and put in node */
 	if (tbl->it_busno) {
@@ -1112,10 +1114,40 @@ static void pnv_pci_ioda1_tce_invalidate(struct pnv_ioda_pe *pe,
 	 */
 }
 
-static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
-					 struct iommu_table *tbl,
-					 __be64 *startp, __be64 *endp, bool rm)
+static int pnv_ioda1_tce_build_vm(struct iommu_table *tbl, long index,
+		long npages, unsigned long uaddr,
+		enum dma_data_direction direction,
+		struct dma_attrs *attrs)
 {
+	long ret = pnv_tce_build(tbl, index, npages, uaddr, direction,
+			attrs);
+
+	if (!ret && (tbl->it_type & TCE_PCI_SWINV_CREATE))
+		pnv_pci_ioda1_tce_invalidate(tbl, index, npages, false);
+
+	return ret;
+}
+
+static void pnv_ioda1_tce_free_vm(struct iommu_table *tbl, long index,
+		long npages)
+{
+	pnv_tce_free(tbl, index, npages);
+
+	if (tbl->it_type & TCE_PCI_SWINV_FREE)
+		pnv_pci_ioda1_tce_invalidate(tbl, index, npages, false);
+}
+
+struct iommu_table_ops pnv_ioda1_iommu_ops = {
+	.set = pnv_ioda1_tce_build_vm,
+	.clear = pnv_ioda1_tce_free_vm,
+	.get = pnv_tce_get,
+};
+
+static void pnv_pci_ioda2_tce_invalidate(struct iommu_table *tbl,
+		unsigned long index, unsigned long npages, bool rm)
+{
+	struct pnv_ioda_pe *pe = container_of(tbl->it_group,
+			struct pnv_ioda_pe, table_group);
 	unsigned long start, end, inc;
 	__be64 __iomem *invalidate = rm ?
 		(__be64 __iomem *)pe->tce_inval_reg_phys :
@@ -1128,9 +1160,9 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
 	end = start;
 
 	/* Figure out the start, end and step */
-	inc = tbl->it_offset + (((u64)startp - tbl->it_base) / sizeof(u64));
+	inc = tbl->it_offset + index / sizeof(u64);
 	start |= (inc << shift);
-	inc = tbl->it_offset + (((u64)endp - tbl->it_base) / sizeof(u64));
+	inc = tbl->it_offset + (index + npages - 1) / sizeof(u64);
 	end |= (inc << shift);
 	inc = (0x1ull << shift);
 	mb();
@@ -1144,19 +1176,35 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
 	}
 }
 
-void pnv_pci_ioda_tce_invalidate(struct iommu_table *tbl,
-				 __be64 *startp, __be64 *endp, bool rm)
+static int pnv_ioda2_tce_build_vm(struct iommu_table *tbl, long index,
+		long npages, unsigned long uaddr,
+		enum dma_data_direction direction,
+		struct dma_attrs *attrs)
 {
-	struct pnv_ioda_pe *pe = container_of(tbl->it_group, struct pnv_ioda_pe,
-					      table_group);
-	struct pnv_phb *phb = pe->phb;
-
-	if (phb->type == PNV_PHB_IODA1)
-		pnv_pci_ioda1_tce_invalidate(pe, tbl, startp, endp, rm);
-	else
-		pnv_pci_ioda2_tce_invalidate(pe, tbl, startp, endp, rm);
+	long ret = pnv_tce_build(tbl, index, npages, uaddr, direction,
+			attrs);
+
+	if (!ret && (tbl->it_type & TCE_PCI_SWINV_CREATE))
+		pnv_pci_ioda2_tce_invalidate(tbl, index, npages, false);
+
+	return ret;
 }
 
+static void pnv_ioda2_tce_free_vm(struct iommu_table *tbl, long index,
+		long npages)
+{
+	pnv_tce_free(tbl, index, npages);
+
+	if (tbl->it_type & TCE_PCI_SWINV_FREE)
+		pnv_pci_ioda2_tce_invalidate(tbl, index, npages, false);
+}
+
+static struct iommu_table_ops pnv_ioda2_iommu_ops = {
+	.set = pnv_ioda2_tce_build_vm,
+	.clear = pnv_ioda2_tce_free_vm,
+	.get = pnv_tce_get,
+};
+
 static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 				      struct pnv_ioda_pe *pe, unsigned int base,
 				      unsigned int segs)
@@ -1236,7 +1284,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 				 TCE_PCI_SWINV_FREE   |
 				 TCE_PCI_SWINV_PAIR);
 	}
-	tbl->it_ops = &pnv_iommu_ops;
+	tbl->it_ops = &pnv_ioda1_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
 			pe->pe_number);
@@ -1387,7 +1435,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				8);
 		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
 	}
-	tbl->it_ops = &pnv_iommu_ops;
+	tbl->it_ops = &pnv_ioda2_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
 	pe->table_group.ops = &pnv_pci_ioda2_ops;
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index ff68cac..6906a9c 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -83,11 +83,18 @@ static void pnv_pci_init_p5ioc2_msis(struct pnv_phb *phb)
 static void pnv_pci_init_p5ioc2_msis(struct pnv_phb *phb) { }
 #endif /* CONFIG_PCI_MSI */
 
+static struct iommu_table_ops pnv_p5ioc2_iommu_ops = {
+	.set = pnv_tce_build,
+	.clear = pnv_tce_free,
+	.get = pnv_tce_get,
+};
+
 static void pnv_pci_p5ioc2_dma_dev_setup(struct pnv_phb *phb,
 					 struct pci_dev *pdev)
 {
 	if (phb->p5ioc2.table_group.tables[0].it_map == NULL) {
-		phb->p5ioc2.table_group.tables[0].it_ops = &pnv_iommu_ops;
+		phb->p5ioc2.table_group.tables[0].it_ops =
+				&pnv_p5ioc2_iommu_ops;
 		iommu_init_table(&phb->p5ioc2.table_group.tables[0],
 				phb->hose->node);
 		iommu_register_group(&phb->p5ioc2.table_group,
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 3050cc8..a8c05de 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -589,70 +589,48 @@ struct pci_ops pnv_pci_ops = {
 	.write = pnv_pci_write_config,
 };
 
-static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
-			 unsigned long uaddr, enum dma_data_direction direction,
-			 struct dma_attrs *attrs, bool rm)
+static __be64 *pnv_tce(struct iommu_table *tbl, long index)
+{
+	__be64 *tmp = ((__be64 *)tbl->it_base);
+
+	return tmp + index;
+}
+
+int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
+		unsigned long uaddr, enum dma_data_direction direction,
+		struct dma_attrs *attrs)
 {
 	u64 proto_tce = iommu_direction_to_tce_perm(direction);
-	__be64 *tcep, *tces;
-	u64 rpn;
+	u64 rpn = __pa(uaddr) >> tbl->it_page_shift;
+	long i;
 
-	tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
-	rpn = __pa(uaddr) >> tbl->it_page_shift;
+	for (i = 0; i < npages; i++) {
+		unsigned long newtce = proto_tce |
+				((rpn + i) << tbl->it_page_shift);
+		unsigned long idx = index - tbl->it_offset + i;
 
-	while (npages--)
-		*(tcep++) = cpu_to_be64(proto_tce |
-				(rpn++ << tbl->it_page_shift));
-
-	/* Some implementations won't cache invalid TCEs and thus may not
-	 * need that flush. We'll probably turn it_type into a bit mask
-	 * of flags if that becomes the case
-	 */
-	if (tbl->it_type & TCE_PCI_SWINV_CREATE)
-		pnv_pci_ioda_tce_invalidate(tbl, tces, tcep - 1, rm);
+		*(pnv_tce(tbl, idx)) = cpu_to_be64(newtce);
+	}
 
 	return 0;
 }
 
-static int pnv_tce_build_vm(struct iommu_table *tbl, long index, long npages,
-			    unsigned long uaddr,
-			    enum dma_data_direction direction,
-			    struct dma_attrs *attrs)
+void pnv_tce_free(struct iommu_table *tbl, long index, long npages)
 {
-	return pnv_tce_build(tbl, index, npages, uaddr, direction, attrs,
-			false);
-}
-
-static void pnv_tce_free(struct iommu_table *tbl, long index, long npages,
-		bool rm)
-{
-	__be64 *tcep, *tces;
-
-	tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
+	long i;
 
-	while (npages--)
-		*(tcep++) = cpu_to_be64(0);
+	for (i = 0; i < npages; i++) {
+		unsigned long idx = index - tbl->it_offset + i;
 
-	if (tbl->it_type & TCE_PCI_SWINV_FREE)
-		pnv_pci_ioda_tce_invalidate(tbl, tces, tcep - 1, rm);
+		*(pnv_tce(tbl, idx)) = cpu_to_be64(0);
+	}
 }
 
-static void pnv_tce_free_vm(struct iommu_table *tbl, long index, long npages)
+unsigned long pnv_tce_get(struct iommu_table *tbl, long index)
 {
-	pnv_tce_free(tbl, index, npages, false);
+	return *(pnv_tce(tbl, index));
 }
 
-static unsigned long pnv_tce_get(struct iommu_table *tbl, long index)
-{
-	return ((u64 *)tbl->it_base)[index - tbl->it_offset];
-}
-
-struct iommu_table_ops pnv_iommu_ops = {
-	.set = pnv_tce_build_vm,
-	.clear = pnv_tce_free_vm,
-	.get = pnv_tce_get,
-};
-
 void pnv_pci_setup_iommu_table(struct iommu_table *tbl,
 			       void *tce_mem, u64 tce_size,
 			       u64 dma_offset, unsigned page_shift)
@@ -685,7 +663,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
 		return NULL;
 	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
 				  be32_to_cpup(sizep), 0, IOMMU_PAGE_SHIFT_4K);
-	tbl->it_ops = &pnv_iommu_ops;
+	tbl->it_ops = &pnv_ioda1_iommu_ops;
 	iommu_init_table(tbl, hose->node);
 	iommu_register_group(tbl->it_group, pci_domain_nr(hose->bus), 0);
 
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 762d906..0d4df32 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -216,7 +216,12 @@ extern struct pci_ops pnv_pci_ops;
 #ifdef CONFIG_EEH
 extern struct pnv_eeh_ops ioda_eeh_ops;
 #endif
-extern struct iommu_table_ops pnv_iommu_ops;
+extern int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
+		unsigned long uaddr, enum dma_data_direction direction,
+		struct dma_attrs *attrs);
+extern void pnv_tce_free(struct iommu_table *tbl, long index, long npages);
+extern unsigned long pnv_tce_get(struct iommu_table *tbl, long index);
+extern struct iommu_table_ops pnv_ioda1_iommu_ops;
 
 void pnv_pci_dump_phb_diag_data(struct pci_controller *hose,
 				unsigned char *log_buff);
-- 
2.0.0

[PATCH kernel v6 18/29] powerpc/iommu/powernv: Release replaced TCE

[Alexey Kardashevskiy]

At the moment writing new TCE value to the IOMMU table fails with EBUSY
if there is a valid entry already. However PAPR specification allows
the guest to write new TCE value without clearing it first.

Another problem this patch is addressing is the use of pool locks for
external IOMMU users such as VFIO. The pool locks are to protect
DMA page allocator rather than entries and since the host kernel does
not control what pages are in use, there is no point in pool locks and
exchange()+put_page(oldtce) is sufficient to avoid possible races.

This adds an exchange() callback to iommu_table_ops which does the same
thing as set() plus it returns replaced TCE and DMA direction so
the caller can release the pages afterwards.

The returned old TCE value is a virtual address as the new TCE value.
This is different from tce_clear() which returns a physical address.

This implements exchange() for P5IOC2/IODA/IODA2. This adds a requirement
for a platform to have exchange() implemented in order to support VFIO.

This replaces iommu_tce_build() and iommu_clear_tce() with
a single iommu_tce_xchg().

This makes sure that TCE permission bits are not set in TCE passed to
IOMMU API as those are to be calculated by platform code from DMA direction.

This moves SetPageDirty() to the IOMMU code to make it work for both
VFIO ioctl interface in in-kernel TCE acceleration (when it becomes
available later).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h            | 15 +++++--
 arch/powerpc/kernel/iommu.c                 | 54 ++++++++++---------------
 arch/powerpc/platforms/powernv/pci-ioda.c   | 26 ++++++++++++
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |  1 +
 arch/powerpc/platforms/powernv/pci.c        | 15 +++++++
 arch/powerpc/platforms/powernv/pci.h        |  2 +
 drivers/vfio/vfio_iommu_spapr_tce.c         | 62 ++++++++++++++++++-----------
 7 files changed, 113 insertions(+), 62 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index d1f8c6c..6af22a4 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -44,11 +44,20 @@ extern int iommu_is_off;
 extern int iommu_force_on;
 
 struct iommu_table_ops {
+	/* When called with direction==DMA_NONE, it is equal to clear() */
 	int (*set)(struct iommu_table *tbl,
 			long index, long npages,
 			unsigned long uaddr,
 			enum dma_data_direction direction,
 			struct dma_attrs *attrs);
+	/*
+	 * Exchanges existing TCE with new TCE plus direction bits;
+	 * returns old TCE and DMA direction mask
+	 */
+	int (*exchange)(struct iommu_table *tbl,
+			long index,
+			unsigned long *tce,
+			enum dma_data_direction *direction);
 	void (*clear)(struct iommu_table *tbl,
 			long index, long npages);
 	unsigned long (*get)(struct iommu_table *tbl, long index);
@@ -231,10 +240,8 @@ extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
 		unsigned long npages);
 extern int iommu_tce_put_param_check(struct iommu_table *tbl,
 		unsigned long ioba, unsigned long tce);
-extern int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
-		unsigned long hwaddr, enum dma_data_direction direction);
-extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
-		unsigned long entry);
+extern long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
+		unsigned long *tce, enum dma_data_direction *direction);
 
 extern void iommu_flush_tce(struct iommu_table *tbl);
 extern int iommu_take_ownership(struct iommu_table_group *table_group);
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index df888a7..2856a4a 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -982,9 +982,6 @@ EXPORT_SYMBOL_GPL(iommu_tce_clear_param_check);
 int iommu_tce_put_param_check(struct iommu_table *tbl,
 		unsigned long ioba, unsigned long tce)
 {
-	if (!(tce & (TCE_PCI_WRITE | TCE_PCI_READ)))
-		return -EINVAL;
-
 	if (tce & ~(IOMMU_PAGE_MASK(tbl) | TCE_PCI_WRITE | TCE_PCI_READ))
 		return -EINVAL;
 
@@ -1002,44 +999,23 @@ int iommu_tce_put_param_check(struct iommu_table *tbl,
 }
 EXPORT_SYMBOL_GPL(iommu_tce_put_param_check);
 
-unsigned long iommu_clear_tce(struct iommu_table *tbl, unsigned long entry)
-{
-	unsigned long oldtce;
-	struct iommu_pool *pool = get_pool(tbl, entry);
-
-	spin_lock(&(pool->lock));
-
-	oldtce = tbl->it_ops->get(tbl, entry);
-	if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ))
-		tbl->it_ops->clear(tbl, entry, 1);
-	else
-		oldtce = 0;
-
-	spin_unlock(&(pool->lock));
-
-	return oldtce;
-}
-EXPORT_SYMBOL_GPL(iommu_clear_tce);
-
 /*
  * hwaddr is a kernel virtual address here (0xc... bazillion),
  * tce_build converts it to a physical address.
  */
-int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
-		unsigned long hwaddr, enum dma_data_direction direction)
+long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
+		unsigned long *tce, enum dma_data_direction *direction)
 {
-	int ret = -EBUSY;
-	unsigned long oldtce;
-	struct iommu_pool *pool = get_pool(tbl, entry);
+	long ret;
 
-	spin_lock(&(pool->lock));
+	if (*tce & ~IOMMU_PAGE_MASK(tbl))
+		return -EINVAL;
 
-	oldtce = tbl->it_ops->get(tbl, entry);
-	/* Add new entry if it is not busy */
-	if (!(oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)))
-		ret = tbl->it_ops->set(tbl, entry, 1, hwaddr, direction, NULL);
+	ret = tbl->it_ops->exchange(tbl, entry, tce, direction);
 
-	spin_unlock(&(pool->lock));
+	if (!ret && ((*direction == DMA_FROM_DEVICE) ||
+			(*direction == DMA_BIDIRECTIONAL)))
+		SetPageDirty(pfn_to_page(__pa(tce) >> PAGE_SHIFT));
 
 	/* if (unlikely(ret))
 		pr_err("iommu_tce: %s failed on hwaddr=%lx ioba=%lx kva=%lx ret=%d\n",
@@ -1048,13 +1024,23 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(iommu_tce_build);
+EXPORT_SYMBOL_GPL(iommu_tce_xchg);
 
 static int iommu_table_take_ownership(struct iommu_table *tbl)
 {
 	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
 	int ret = 0;
 
+	/*
+	 * VFIO does not control TCE entries allocation and the guest
+	 * can write new TCEs on top of existing ones so iommu_tce_build()
+	 * must be able to release old pages. This functionality
+	 * requires exchange() callback defined so if it is not
+	 * implemented, we disallow taking ownership over the table.
+	 */
+	if (!tbl->it_ops->exchange)
+		return -EINVAL;
+
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);
 	for (i = 0; i < tbl->nr_pools; i++)
 		spin_lock(&tbl->pools[i].lock);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index fd993bc..9691b3a 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1128,6 +1128,18 @@ static int pnv_ioda1_tce_build_vm(struct iommu_table *tbl, long index,
 	return ret;
 }
 
+static int pnv_ioda1_tce_xchg_vm(struct iommu_table *tbl, long index,
+		unsigned long *tce, enum dma_data_direction *direction)
+{
+	long ret = pnv_tce_xchg(tbl, index, tce, direction);
+
+	if (!ret && (tbl->it_type &
+			(TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE)))
+		pnv_pci_ioda1_tce_invalidate(tbl, index, 1, false);
+
+	return ret;
+}
+
 static void pnv_ioda1_tce_free_vm(struct iommu_table *tbl, long index,
 		long npages)
 {
@@ -1139,6 +1151,7 @@ static void pnv_ioda1_tce_free_vm(struct iommu_table *tbl, long index,
 
 struct iommu_table_ops pnv_ioda1_iommu_ops = {
 	.set = pnv_ioda1_tce_build_vm,
+	.exchange = pnv_ioda1_tce_xchg_vm,
 	.clear = pnv_ioda1_tce_free_vm,
 	.get = pnv_tce_get,
 };
@@ -1190,6 +1203,18 @@ static int pnv_ioda2_tce_build_vm(struct iommu_table *tbl, long index,
 	return ret;
 }
 
+static int pnv_ioda2_tce_xchg_vm(struct iommu_table *tbl, long index,
+		unsigned long *tce, enum dma_data_direction *direction)
+{
+	long ret = pnv_tce_xchg(tbl, index, tce, direction);
+
+	if (!ret && (tbl->it_type &
+			(TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE)))
+		pnv_pci_ioda2_tce_invalidate(tbl, index, 1, false);
+
+	return ret;
+}
+
 static void pnv_ioda2_tce_free_vm(struct iommu_table *tbl, long index,
 		long npages)
 {
@@ -1201,6 +1226,7 @@ static void pnv_ioda2_tce_free_vm(struct iommu_table *tbl, long index,
 
 static struct iommu_table_ops pnv_ioda2_iommu_ops = {
 	.set = pnv_ioda2_tce_build_vm,
+	.exchange = pnv_ioda2_tce_xchg_vm,
 	.clear = pnv_ioda2_tce_free_vm,
 	.get = pnv_tce_get,
 };
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index 6906a9c..5888b2c 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -85,6 +85,7 @@ static void pnv_pci_init_p5ioc2_msis(struct pnv_phb *phb) { }
 
 static struct iommu_table_ops pnv_p5ioc2_iommu_ops = {
 	.set = pnv_tce_build,
+	.exchange = pnv_tce_xchg,
 	.clear = pnv_tce_free,
 	.get = pnv_tce_get,
 };
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index a8c05de..c5e1f05 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -615,6 +615,21 @@ int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
 	return 0;
 }
 
+int pnv_tce_xchg(struct iommu_table *tbl, long index,
+		unsigned long *tce, enum dma_data_direction *direction)
+{
+	u64 proto_tce = iommu_direction_to_tce_perm(*direction);
+	unsigned long newtce =  __pa(*tce) | proto_tce;
+	unsigned long idx = index - tbl->it_offset;
+
+	*tce = xchg(pnv_tce(tbl, idx), cpu_to_be64(newtce));
+	*tce = (unsigned long) __va(be64_to_cpu(*tce));
+	*direction = iommu_tce_direction(*tce);
+	*tce &= ~(TCE_PCI_READ | TCE_PCI_WRITE);
+
+	return 0;
+}
+
 void pnv_tce_free(struct iommu_table *tbl, long index, long npages)
 {
 	long i;
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 0d4df32..4d1a78c 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -220,6 +220,8 @@ extern int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
 		unsigned long uaddr, enum dma_data_direction direction,
 		struct dma_attrs *attrs);
 extern void pnv_tce_free(struct iommu_table *tbl, long index, long npages);
+extern int pnv_tce_xchg(struct iommu_table *tbl, long index,
+		unsigned long *tce, enum dma_data_direction *direction);
 extern unsigned long pnv_tce_get(struct iommu_table *tbl, long index);
 extern struct iommu_table_ops pnv_ioda1_iommu_ops;
 
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 7f62e92..9d240b4 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -446,9 +446,6 @@ static void tce_iommu_unuse_page(struct tce_container *container,
 {
 	struct page *page;
 
-	if (!(oldtce & (TCE_PCI_READ | TCE_PCI_WRITE)))
-		return;
-
 	/*
 	 * VFIO cannot map/unmap when a container is not enabled so
 	 * we would not need this check but KVM could map/unmap and if
@@ -458,14 +455,10 @@ static void tce_iommu_unuse_page(struct tce_container *container,
 	if (!container->enabled)
 		return;
 
-	page = pfn_to_page(__pa(oldtce) >> PAGE_SHIFT);
-
-	if (oldtce & TCE_PCI_WRITE)
-		SetPageDirty(page);
-
 	if (tce_preregistered(container))
 		return;
 
+	page = pfn_to_page(__pa(oldtce) >> PAGE_SHIFT);
 	put_page(page);
 }
 
@@ -473,14 +466,19 @@ static int tce_iommu_clear(struct tce_container *container,
 		struct iommu_table *tbl,
 		unsigned long entry, unsigned long pages)
 {
-	unsigned long oldtce;
+	long ret;
+	enum dma_data_direction direction;
+	unsigned long tce;
 
 	for ( ; pages; --pages, ++entry) {
-		oldtce = iommu_clear_tce(tbl, entry);
-		if (!oldtce)
+		direction = DMA_NONE;
+		tce = (unsigned long) __va(0);
+		ret = iommu_tce_xchg(tbl, entry, &tce, &direction);
+		if (ret)
 			continue;
 
-		tce_iommu_unuse_page(container, (unsigned long) __va(oldtce));
+		if (direction != DMA_NONE)
+			tce_iommu_unuse_page(container, tce);
 	}
 
 	return 0;
@@ -521,12 +519,13 @@ static int tce_get_hva_cached(struct tce_container *container,
 
 static long tce_iommu_build(struct tce_container *container,
 		struct iommu_table *tbl,
-		unsigned long entry, unsigned long tce, unsigned long pages)
+		unsigned long entry, unsigned long tce, unsigned long pages,
+		enum dma_data_direction direction)
 {
 	long i, ret = 0;
 	struct page *page;
 	unsigned long hva;
-	enum dma_data_direction direction = iommu_tce_direction(tce);
+	enum dma_data_direction dirtmp;
 
 	for (i = 0; i < pages; ++i) {
 		if (tce_preregistered(container))
@@ -546,15 +545,21 @@ static long tce_iommu_build(struct tce_container *container,
 
 		/* Preserve offset within IOMMU page */
 		hva |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
+		dirtmp = direction;
 
-		ret = iommu_tce_build(tbl, entry + i, hva, direction);
+		ret = iommu_tce_xchg(tbl, entry + i, &hva, &dirtmp);
 		if (ret) {
+			/* dirtmp cannot be DMA_NONE here */
 			tce_iommu_unuse_page(container, hva);
 			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(container, hva);
+
 		tce += IOMMU_PAGE_SIZE(tbl);
 	}
 
@@ -619,7 +624,7 @@ static long tce_iommu_ioctl(void *iommu_data,
 	case VFIO_IOMMU_MAP_DMA: {
 		struct vfio_iommu_type1_dma_map param;
 		struct iommu_table *tbl;
-		unsigned long tce;
+		enum dma_data_direction direction;
 
 		if (!container->enabled)
 			return -EPERM;
@@ -640,24 +645,33 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (!tbl)
 			return -ENXIO;
 
-		if ((param.size & ~IOMMU_PAGE_MASK(tbl)) ||
-				(param.vaddr & ~IOMMU_PAGE_MASK(tbl)))
+		if (param.size & ~IOMMU_PAGE_MASK(tbl))
+			return -EINVAL;
+
+		if (param.vaddr & (TCE_PCI_READ | TCE_PCI_WRITE))
 			return -EINVAL;
 
 		/* iova is checked by the IOMMU API */
-		tce = param.vaddr;
 		if (param.flags & VFIO_DMA_MAP_FLAG_READ)
-			tce |= TCE_PCI_READ;
-		if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
-			tce |= TCE_PCI_WRITE;
+			if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
+				direction = DMA_BIDIRECTIONAL;
+			else
+				direction = DMA_TO_DEVICE;
+		else
+			if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
+				direction = DMA_FROM_DEVICE;
+			else
+				return -EINVAL;
 
-		ret = iommu_tce_put_param_check(tbl, param.iova, tce);
+		ret = iommu_tce_put_param_check(tbl, param.iova, param.vaddr);
 		if (ret)
 			return ret;
 
 		ret = tce_iommu_build(container, tbl,
 				param.iova >> tbl->it_page_shift,
-				tce, param.size >> tbl->it_page_shift);
+				param.vaddr,
+				param.size >> tbl->it_page_shift,
+				direction);
 
 		iommu_flush_tce(tbl);
 
-- 
2.0.0

[PATCH kernel v6 19/29] powerpc/powernv/ioda2: Rework iommu_table creation

[Alexey Kardashevskiy]

This moves iommu_table creation to the beginning. This is a mechanical
patch.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 9691b3a..9486b07b 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1427,27 +1427,31 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	addr = page_address(tce_mem);
 	memset(addr, 0, tce_table_size);
 
+	/* Setup iommu */
+	pe->table_group.tables[0].it_group = &pe->table_group;
+
+	/* Setup linux iommu table */
+	tbl = &pe->table_group.tables[0];
+	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
+			IOMMU_PAGE_SHIFT_4K);
+
+	tbl->it_ops = &pnv_ioda2_iommu_ops;
+	iommu_init_table(tbl, phb->hose->node);
+	pe->table_group.ops = &pnv_pci_ioda2_ops;
+
 	/*
 	 * Map TCE table through TVT. The TVE index is the PE number
 	 * shifted by 1 bit for 32-bits DMA space.
 	 */
 	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
-					pe->pe_number << 1, 1, __pa(addr),
-					tce_table_size, 0x1000);
+			pe->pe_number << 1, 1, __pa(tbl->it_base),
+			tbl->it_size << 3, 1ULL << tbl->it_page_shift);
 	if (rc) {
 		pe_err(pe, "Failed to configure 32-bit TCE table,"
 		       " err %ld\n", rc);
 		goto fail;
 	}
 
-	/* Setup iommu */
-	pe->table_group.tables[0].it_group = &pe->table_group;
-
-	/* Setup linux iommu table */
-	tbl = &pe->table_group.tables[0];
-	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
-			IOMMU_PAGE_SHIFT_4K);
-
 	/* OPAL variant of PHB3 invalidated TCEs */
 	swinvp = of_get_property(phb->hose->dn, "ibm,opal-tce-kill", NULL);
 	if (swinvp) {
@@ -1461,14 +1465,12 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				8);
 		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
 	}
-	tbl->it_ops = &pnv_ioda2_iommu_ops;
-	iommu_init_table(tbl, phb->hose->node);
-	pe->table_group.ops = &pnv_pci_ioda2_ops;
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
 			pe->pe_number);
 
 	if (pe->pdev)
-		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);
+		set_iommu_table_base_and_group(&pe->pdev->dev,
+				&pe->table_group.tables[0]);
 	else
 		pnv_ioda_setup_bus_dma(pe, pe->pbus, true);
 
-- 
2.0.0

[PATCH kernel v6 20/29] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table/pnc_pci_free_table

[Alexey Kardashevskiy]

This is a part of moving TCE table allocation into an iommu_ops
callback to support multiple IOMMU groups per one VFIO container.

This enforce window size to be a power of two.

This is a pretty mechanical patch.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 88 +++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 9486b07b..af9208c 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -24,7 +24,9 @@
 #include <linux/msi.h>
 #include <linux/memblock.h>
 #include <linux/iommu.h>
+#include <linux/mmzone.h>
 
+#include <asm/mmzone.h>
 #include <asm/sections.h>
 #include <asm/io.h>
 #include <asm/prom.h>
@@ -1329,6 +1331,61 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 		__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
 }
 
+static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
+		__u32 page_shift, __u64 window_size,
+		struct iommu_table *tbl)
+{
+	int nid = pe->phb->hose->node;
+	struct page *tce_mem = NULL;
+	void *addr;
+	unsigned long tce_table_size;
+	int64_t rc;
+	unsigned order;
+
+	if (!(table_group->pgsizes & (1ULL << page_shift)))
+		return -EINVAL;
+
+	if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
+		return -EINVAL;
+
+	tce_table_size = (window_size >> page_shift) * 8;
+	tce_table_size = max(0x1000UL, tce_table_size);
+
+	/* Allocate TCE table */
+	order = get_order(tce_table_size);
+
+	tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
+	if (!tce_mem) {
+		pr_err("Failed to allocate a TCE memory, order=%d\n", order);
+		rc = -ENOMEM;
+		goto fail;
+	}
+	addr = page_address(tce_mem);
+	memset(addr, 0, tce_table_size);
+
+	/* Setup linux iommu table */
+	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
+			page_shift);
+
+	tbl->it_ops = &pnv_ioda2_iommu_ops;
+
+	return 0;
+fail:
+	if (tce_mem)
+		__free_pages(tce_mem, get_order(tce_table_size));
+
+	return rc;
+}
+
+static void pnv_pci_free_table(struct iommu_table *tbl)
+{
+	if (!tbl->it_size)
+		return;
+
+	free_pages(tbl->it_base, get_order(tbl->it_size << 3));
+	memset(tbl, 0, sizeof(struct iommu_table));
+}
+
 static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
 {
 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
@@ -1399,11 +1456,9 @@ static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
 static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				       struct pnv_ioda_pe *pe)
 {
-	struct page *tce_mem = NULL;
-	void *addr;
 	const __be64 *swinvp;
-	struct iommu_table *tbl;
-	unsigned int tce_table_size, end;
+	unsigned int end;
+	struct iommu_table *tbl = &pe->table_group.tables[0];
 	int64_t rc;
 
 	/* We shouldn't already have a 32-bit DMA associated */
@@ -1412,30 +1467,20 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 
 	/* The PE will reserve all possible 32-bits space */
 	pe->tce32_seg = 0;
+
 	end = (1 << ilog2(phb->ioda.m32_pci_base));
-	tce_table_size = (end / 0x1000) * 8;
 	pe_info(pe, "Setting up 32-bit TCE table at 0..%08x\n",
 		end);
 
-	/* Allocate TCE table */
-	tce_mem = alloc_pages_node(phb->hose->node, GFP_KERNEL,
-				   get_order(tce_table_size));
-	if (!tce_mem) {
-		pe_err(pe, "Failed to allocate a 32-bit TCE memory\n");
-		goto fail;
+	rc = pnv_pci_ioda2_create_table(pe, IOMMU_PAGE_SHIFT_4K,
+			phb->ioda.m32_pci_base, tbl);
+	if (rc) {
+		pe_err(pe, "Failed to create 32-bit TCE table, err %ld", rc);
+		return;
 	}
-	addr = page_address(tce_mem);
-	memset(addr, 0, tce_table_size);
 
 	/* Setup iommu */
 	pe->table_group.tables[0].it_group = &pe->table_group;
-
-	/* Setup linux iommu table */
-	tbl = &pe->table_group.tables[0];
-	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
-			IOMMU_PAGE_SHIFT_4K);
-
-	tbl->it_ops = &pnv_ioda2_iommu_ops;
 	iommu_init_table(tbl, phb->hose->node);
 	pe->table_group.ops = &pnv_pci_ioda2_ops;
 
@@ -1482,8 +1527,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 fail:
 	if (pe->tce32_seg >= 0)
 		pe->tce32_seg = -1;
-	if (tce_mem)
-		__free_pages(tce_mem, get_order(tce_table_size));
+	pnv_pci_free_table(tbl);
 }
 
 static void pnv_ioda_setup_dma(struct pnv_phb *phb)
-- 
2.0.0

[PATCH kernel v6 21/29] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window

[Alexey Kardashevskiy]

This is a part of moving DMA window programming to an iommu_ops
callback.

This is a mechanical patch.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 85 ++++++++++++++++++++-----------
 1 file changed, 56 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index af9208c..8bb5d6d 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1386,6 +1386,57 @@ static void pnv_pci_free_table(struct iommu_table *tbl)
 	memset(tbl, 0, sizeof(struct iommu_table));
 }
 
+static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
+		struct iommu_table *tbl)
+{
+	struct pnv_phb *phb = pe->phb;
+	const __be64 *swinvp;
+	int64_t rc;
+	const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
+	const __u64 win_size = tbl->it_size << tbl->it_page_shift;
+
+	pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx\n",
+			start_addr, start_addr + win_size - 1,
+			1UL << tbl->it_page_shift, tbl->it_size << 3);
+
+	pe->table_group.tables[0] = *tbl;
+	tbl = &pe->table_group.tables[0];
+	tbl->it_group = &pe->table_group;
+
+	/*
+	 * Map TCE table through TVT. The TVE index is the PE number
+	 * shifted by 1 bit for 32-bits DMA space.
+	 */
+	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
+			pe->pe_number << 1, 1, __pa(tbl->it_base),
+			tbl->it_size << 3, 1ULL << tbl->it_page_shift);
+	if (rc) {
+		pe_err(pe, "Failed to configure TCE table, err %ld\n", rc);
+		goto fail;
+	}
+
+	/* OPAL variant of PHB3 invalidated TCEs */
+	swinvp = of_get_property(phb->hose->dn, "ibm,opal-tce-kill", NULL);
+	if (swinvp) {
+		/* We need a couple more fields -- an address and a data
+		 * to or.  Since the bus is only printed out on table free
+		 * errors, and on the first pass the data will be a relative
+		 * bus number, print that out instead.
+		 */
+		pe->tce_inval_reg_phys = be64_to_cpup(swinvp);
+		tbl->it_index = (unsigned long)ioremap(pe->tce_inval_reg_phys,
+				8);
+		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
+	}
+
+	return 0;
+fail:
+	if (pe->tce32_seg >= 0)
+		pe->tce32_seg = -1;
+
+	return rc;
+}
+
 static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
 {
 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
@@ -1456,7 +1507,6 @@ static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
 static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 				       struct pnv_ioda_pe *pe)
 {
-	const __be64 *swinvp;
 	unsigned int end;
 	struct iommu_table *tbl = &pe->table_group.tables[0];
 	int64_t rc;
@@ -1484,31 +1534,14 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	iommu_init_table(tbl, phb->hose->node);
 	pe->table_group.ops = &pnv_pci_ioda2_ops;
 
-	/*
-	 * Map TCE table through TVT. The TVE index is the PE number
-	 * shifted by 1 bit for 32-bits DMA space.
-	 */
-	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
-			pe->pe_number << 1, 1, __pa(tbl->it_base),
-			tbl->it_size << 3, 1ULL << tbl->it_page_shift);
+	rc = pnv_pci_ioda2_set_window(pe, tbl);
 	if (rc) {
 		pe_err(pe, "Failed to configure 32-bit TCE table,"
 		       " err %ld\n", rc);
-		goto fail;
-	}
-
-	/* OPAL variant of PHB3 invalidated TCEs */
-	swinvp = of_get_property(phb->hose->dn, "ibm,opal-tce-kill", NULL);
-	if (swinvp) {
-		/* We need a couple more fields -- an address and a data
-		 * to or.  Since the bus is only printed out on table free
-		 * errors, and on the first pass the data will be a relative
-		 * bus number, print that out instead.
-		 */
-		pe->tce_inval_reg_phys = be64_to_cpup(swinvp);
-		tbl->it_index = (unsigned long)ioremap(pe->tce_inval_reg_phys,
-				8);
-		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
+		pnv_pci_free_table(tbl);
+		if (pe->tce32_seg >= 0)
+			pe->tce32_seg = -1;
+		return;
 	}
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
 			pe->pe_number);
@@ -1522,12 +1555,6 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	/* Also create a bypass window */
 	if (!pnv_iommu_bypass_disabled)
 		pnv_pci_ioda2_setup_bypass_pe(phb, pe);
-
-	return;
-fail:
-	if (pe->tce32_seg >= 0)
-		pe->tce32_seg = -1;
-	pnv_pci_free_table(tbl);
 }
 
 static void pnv_ioda_setup_dma(struct pnv_phb *phb)
-- 
2.0.0

[PATCH kernel v6 22/29] powerpc/iommu: Split iommu_free_table into 2 helpers

[Alexey Kardashevskiy]

The iommu_free_table helper release memory it is using (the TCE table and
@it_map) and release the iommu_table struct as well. We might not want
the very last step as we store iommu_table in parent structures.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h |  1 +
 arch/powerpc/kernel/iommu.c      | 57 ++++++++++++++++++++++++----------------
 2 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 6af22a4..fd118ea 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -125,6 +125,7 @@ static inline void *get_iommu_table_base(struct device *dev)
 
 extern struct iommu_table *iommu_table_alloc(int node);
 /* Frees table for an individual device node */
+extern void iommu_reset_table(struct iommu_table *tbl, const char *node_name);
 extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
 
 /* Initializes an iommu_table based in values set in the passed-in
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 2856a4a..3500bd0 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -721,24 +721,46 @@ struct iommu_table *iommu_table_alloc(int node)
 	return &table_group->tables[0];
 }
 
+void iommu_reset_table(struct iommu_table *tbl, const char *node_name)
+{
+	if (!tbl)
+		return;
+
+	if (tbl->it_map) {
+		unsigned long bitmap_sz;
+		unsigned int order;
+
+		/*
+		 * In case we have reserved the first bit, we should not emit
+		 * the warning below.
+		 */
+		if (tbl->it_offset == 0)
+			clear_bit(0, tbl->it_map);
+
+		/* verify that table contains no entries */
+		if (!bitmap_empty(tbl->it_map, tbl->it_size))
+			pr_warn("%s: Unexpected TCEs for %s\n", __func__,
+					node_name);
+
+		/* calculate bitmap size in bytes */
+		bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
+
+		/* free bitmap */
+		order = get_order(bitmap_sz);
+		free_pages((unsigned long) tbl->it_map, order);
+	}
+
+	memset(tbl, 0, sizeof(*tbl));
+}
+
 void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 {
-	unsigned long bitmap_sz;
-	unsigned int order;
 	struct iommu_table_group *table_group = tbl->it_group;
 
-	if (!tbl || !tbl->it_map) {
-		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
-				node_name);
+	if (!tbl)
 		return;
-	}
 
-	/*
-	 * In case we have reserved the first bit, we should not emit
-	 * the warning below.
-	 */
-	if (tbl->it_offset == 0)
-		clear_bit(0, tbl->it_map);
+	iommu_reset_table(tbl, node_name);
 
 #ifdef CONFIG_IOMMU_API
 	if (table_group->group) {
@@ -747,17 +769,6 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 	}
 #endif
 
-	/* verify that table contains no entries */
-	if (!bitmap_empty(tbl->it_map, tbl->it_size))
-		pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
-
-	/* calculate bitmap size in bytes */
-	bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
-
-	/* free bitmap */
-	order = get_order(bitmap_sz);
-	free_pages((unsigned long) tbl->it_map, order);
-
 	/* free table */
 	kfree(table_group);
 }
-- 
2.0.0

[PATCH kernel v6 23/29] powerpc/powernv: Implement multilevel TCE tables

[Alexey Kardashevskiy]

TCE tables might get too big in case of 4K IOMMU pages and DDW enabled
on huge guests (hundreds of GB of RAM) so the kernel might be unable to
allocate contiguous chunk of physical memory to store the TCE table.

To address this, POWER8 CPU (actually, IODA2) supports multi-level TCE tables,
up to 5 levels which splits the table into a tree of smaller subtables.

This adds multi-level TCE tables support to pnv_pci_ioda2_create_table()
and pnv_pci_ioda2_free_table() callbacks.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h          |   2 +
 arch/powerpc/platforms/powernv/pci-ioda.c | 127 ++++++++++++++++++++++++------
 arch/powerpc/platforms/powernv/pci.c      |  19 +++++
 3 files changed, 122 insertions(+), 26 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index fd118ea..4007432 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -88,6 +88,8 @@ struct iommu_pool {
 struct iommu_table {
 	unsigned long  it_busno;     /* Bus number this table belongs to */
 	unsigned long  it_size;      /* Size of iommu table in entries */
+	unsigned long  it_indirect_levels;
+	unsigned long  it_level_size;
 	unsigned long  it_offset;    /* Offset into global table */
 	unsigned long  it_base;      /* mapped address of tce table */
 	unsigned long  it_index;     /* which iommu table this is */
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 8bb5d6d..bdf511d 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -47,6 +47,8 @@
 #include "powernv.h"
 #include "pci.h"
 
+#define POWERNV_IOMMU_DEFAULT_LEVELS	1
+
 static void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
 			    const char *fmt, ...)
 {
@@ -1331,16 +1333,79 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 		__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
 }
 
+static void pnv_free_tce_table(unsigned long addr, unsigned size,
+		unsigned level)
+{
+	addr &= ~(TCE_PCI_READ | TCE_PCI_WRITE);
+
+	if (level) {
+		long i;
+		u64 *tmp = (u64 *) addr;
+
+		for (i = 0; i < size; ++i) {
+			unsigned long hpa = be64_to_cpu(tmp[i]);
+
+			if (!(hpa & (TCE_PCI_READ | TCE_PCI_WRITE)))
+				continue;
+
+			pnv_free_tce_table((unsigned long) __va(hpa),
+					size, level - 1);
+		}
+	}
+
+	free_pages(addr, get_order(size << 3));
+}
+
+static __be64 *pnv_alloc_tce_table(int nid,
+		unsigned shift, unsigned levels, unsigned long *left)
+{
+	struct page *tce_mem = NULL;
+	__be64 *addr, *tmp;
+	unsigned order = max_t(unsigned, shift, PAGE_SHIFT) - PAGE_SHIFT;
+	unsigned long chunk = 1UL << shift, i;
+
+	tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
+	if (!tce_mem) {
+		pr_err("Failed to allocate a TCE memory\n");
+		return NULL;
+	}
+
+	if (!*left)
+		return NULL;
+
+	addr = page_address(tce_mem);
+	memset(addr, 0, chunk);
+
+	--levels;
+	if (!levels) {
+		/* This is last level, actual TCEs */
+		*left -= min(*left, chunk);
+		return addr;
+	}
+
+	for (i = 0; i < (chunk >> 3); ++i) {
+		/* We allocated required TCEs, mark the rest "page fault" */
+		if (!*left) {
+			addr[i] = cpu_to_be64(0);
+			continue;
+		}
+
+		tmp = pnv_alloc_tce_table(nid, shift, levels, left);
+		addr[i] = cpu_to_be64(__pa(tmp) |
+				TCE_PCI_READ | TCE_PCI_WRITE);
+	}
+
+	return addr;
+}
+
 static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
-		__u32 page_shift, __u64 window_size,
+		__u32 page_shift, __u64 window_size, __u32 levels,
 		struct iommu_table *tbl)
 {
 	int nid = pe->phb->hose->node;
-	struct page *tce_mem = NULL;
 	void *addr;
-	unsigned long tce_table_size;
-	int64_t rc;
-	unsigned order;
+	unsigned long tce_table_size, left;
+	unsigned shift;
 
 	if (!(table_group->pgsizes & (1ULL << page_shift)))
 		return -EINVAL;
@@ -1348,20 +1413,27 @@ static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
 	if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
 		return -EINVAL;
 
+	if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS))
+		return -EINVAL;
+
 	tce_table_size = (window_size >> page_shift) * 8;
 	tce_table_size = max(0x1000UL, tce_table_size);
 
 	/* Allocate TCE table */
-	order = get_order(tce_table_size);
+#define ROUND_UP(x, n) (((x) + (n) - 1u) & ~((n) - 1u))
+	shift = ROUND_UP(ilog2(window_size) - page_shift, levels) / levels;
+	shift += 3;
+	shift = max_t(unsigned, shift, IOMMU_PAGE_SHIFT_4K);
+	pr_info("Creating TCE table %08llx, %d levels, TCE table size = %lx\n",
+			window_size, levels, 1UL << shift);
 
-	tce_mem = alloc_pages_node(nid, GFP_KERNEL, order);
-	if (!tce_mem) {
-		pr_err("Failed to allocate a TCE memory, order=%d\n", order);
-		rc = -ENOMEM;
-		goto fail;
-	}
-	addr = page_address(tce_mem);
-	memset(addr, 0, tce_table_size);
+	tbl->it_level_size = 1ULL << (shift - 3);
+	left = tce_table_size;
+	addr = pnv_alloc_tce_table(nid, shift, levels, &left);
+	if (!addr)
+		return -ENOMEM;
+
+	tbl->it_indirect_levels = levels - 1;
 
 	/* Setup linux iommu table */
 	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
@@ -1370,20 +1442,18 @@ static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
 	tbl->it_ops = &pnv_ioda2_iommu_ops;
 
 	return 0;
-fail:
-	if (tce_mem)
-		__free_pages(tce_mem, get_order(tce_table_size));
-
-	return rc;
 }
 
 static void pnv_pci_free_table(struct iommu_table *tbl)
 {
+	const unsigned size = tbl->it_indirect_levels ?
+			tbl->it_level_size : tbl->it_size;
+
 	if (!tbl->it_size)
 		return;
 
-	free_pages(tbl->it_base, get_order(tbl->it_size << 3));
-	memset(tbl, 0, sizeof(struct iommu_table));
+	pnv_free_tce_table(tbl->it_base, size, tbl->it_indirect_levels);
+	iommu_reset_table(tbl, "ioda2");
 }
 
 static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
@@ -1392,12 +1462,15 @@ static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
 	struct pnv_phb *phb = pe->phb;
 	const __be64 *swinvp;
 	int64_t rc;
+	const unsigned size = tbl->it_indirect_levels ?
+			tbl->it_level_size : tbl->it_size;
 	const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
 	const __u64 win_size = tbl->it_size << tbl->it_page_shift;
 
-	pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx\n",
+	pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx levels=%d levelsize=%x\n",
 			start_addr, start_addr + win_size - 1,
-			1UL << tbl->it_page_shift, tbl->it_size << 3);
+			1UL << tbl->it_page_shift, tbl->it_size,
+			tbl->it_indirect_levels + 1, tbl->it_level_size);
 
 	pe->table_group.tables[0] = *tbl;
 	tbl = &pe->table_group.tables[0];
@@ -1408,8 +1481,9 @@ static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
 	 * shifted by 1 bit for 32-bits DMA space.
 	 */
 	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
-			pe->pe_number << 1, 1, __pa(tbl->it_base),
-			tbl->it_size << 3, 1ULL << tbl->it_page_shift);
+			pe->pe_number << 1, tbl->it_indirect_levels + 1,
+			__pa(tbl->it_base),
+			size << 3, 1ULL << tbl->it_page_shift);
 	if (rc) {
 		pe_err(pe, "Failed to configure TCE table, err %ld\n", rc);
 		goto fail;
@@ -1523,7 +1597,8 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 		end);
 
 	rc = pnv_pci_ioda2_create_table(pe, IOMMU_PAGE_SHIFT_4K,
-			phb->ioda.m32_pci_base, tbl);
+			phb->ioda.m32_pci_base,
+			POWERNV_IOMMU_DEFAULT_LEVELS, tbl);
 	if (rc) {
 		pe_err(pe, "Failed to create 32-bit TCE table, err %ld", rc);
 		return;
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index c5e1f05..9b4a0cf 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -592,6 +592,25 @@ struct pci_ops pnv_pci_ops = {
 static __be64 *pnv_tce(struct iommu_table *tbl, long index)
 {
 	__be64 *tmp = ((__be64 *)tbl->it_base);
+	int  level = tbl->it_indirect_levels;
+	const long shift = ilog2(tbl->it_level_size);
+	unsigned long mask = (tbl->it_level_size - 1) << (level * shift);
+
+	if (index >= tbl->it_size)
+		return NULL;
+
+	while (level) {
+		int n = (index & mask) >> (level * shift);
+		unsigned long tce = be64_to_cpu(tmp[n]);
+
+		if (!(tce & (TCE_PCI_READ | TCE_PCI_WRITE)))
+			return NULL;
+
+		tmp = __va(tce & ~(TCE_PCI_READ | TCE_PCI_WRITE));
+		index &= ~mask;
+		mask >>= shift;
+		--level;
+	}
 
 	return tmp + index;
 }
-- 
2.0.0

[PATCH kernel v6 24/29] powerpc/powernv: Change prototypes to receive iommu

[Alexey Kardashevskiy]

This changes few functions to receive a iommu_table_group pointer
rather than PE as they are going to be a part of upcoming
iommu_table_group_ops callback set.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index bdf511d..ca6c3f3 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1398,10 +1398,12 @@ static __be64 *pnv_alloc_tce_table(int nid,
 	return addr;
 }
 
-static long pnv_pci_ioda2_create_table(struct pnv_ioda_pe *pe,
+static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
 		__u32 page_shift, __u64 window_size, __u32 levels,
 		struct iommu_table *tbl)
 {
+	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
+						table_group);
 	int nid = pe->phb->hose->node;
 	void *addr;
 	unsigned long tce_table_size, left;
@@ -1456,9 +1458,11 @@ static void pnv_pci_free_table(struct iommu_table *tbl)
 	iommu_reset_table(tbl, "ioda2");
 }
 
-static long pnv_pci_ioda2_set_window(struct pnv_ioda_pe *pe,
+static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
 		struct iommu_table *tbl)
 {
+	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
+			table_group);
 	struct pnv_phb *phb = pe->phb;
 	const __be64 *swinvp;
 	int64_t rc;
@@ -1591,12 +1595,11 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 
 	/* The PE will reserve all possible 32-bits space */
 	pe->tce32_seg = 0;
-
 	end = (1 << ilog2(phb->ioda.m32_pci_base));
 	pe_info(pe, "Setting up 32-bit TCE table at 0..%08x\n",
 		end);
 
-	rc = pnv_pci_ioda2_create_table(pe, IOMMU_PAGE_SHIFT_4K,
+	rc = pnv_pci_ioda2_create_table(&pe->table_group, IOMMU_PAGE_SHIFT_4K,
 			phb->ioda.m32_pci_base,
 			POWERNV_IOMMU_DEFAULT_LEVELS, tbl);
 	if (rc) {
@@ -1609,7 +1612,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	iommu_init_table(tbl, phb->hose->node);
 	pe->table_group.ops = &pnv_pci_ioda2_ops;
 
-	rc = pnv_pci_ioda2_set_window(pe, tbl);
+	rc = pnv_pci_ioda2_set_window(&pe->table_group, tbl);
 	if (rc) {
 		pe_err(pe, "Failed to configure 32-bit TCE table,"
 		       " err %ld\n", rc);
-- 
2.0.0

[PATCH kernel v6 25/29] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks

[Alexey Kardashevskiy]

This extends iommu_table_group_ops by a set of callbacks to support
dynamic DMA windows management.

query() returns IOMMU capabilities such as default DMA window address and
supported number of DMA windows and TCE table levels.

create_table() creates a TCE table with specific parameters.
it receives iommu_table_group to know nodeid in order to allocate
TCE table memory closer to the PHB. The exact format of allocated
multi-level table might be also specific to the PHB model (not
the case now though).
This callback calculated the DMA window offset on a PCI bus from @num
and stores it in a just created table.

set_window() sets the window at specified TVT index + @num on PHB.

unset_window() unsets the window from specified TVT.

This adds a free() callback to iommu_table_ops to free the memory
(potentially a tree of tables) allocated for the TCE table.

create_table() and free() are supposed to be called once per
VFIO container and set_window()/unset_window() are supposed to be
called for every group in a container.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h            | 21 ++++++++
 arch/powerpc/platforms/powernv/pci-ioda.c   | 84 ++++++++++++++++++++++++-----
 arch/powerpc/platforms/powernv/pci-p5ioc2.c | 11 ++--
 3 files changed, 99 insertions(+), 17 deletions(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 4007432..13145a2 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -62,6 +62,8 @@ struct iommu_table_ops {
 			long index, long npages);
 	unsigned long (*get)(struct iommu_table *tbl, long index);
 	void (*flush)(struct iommu_table *tbl);
+
+	void (*free)(struct iommu_table *tbl);
 };
 
 /* These are used by VIO */
@@ -148,12 +150,31 @@ struct iommu_table_group_ops {
 	 */
 	void (*set_ownership)(struct iommu_table_group *table_group,
 			bool enable);
+
+	long (*create_table)(struct iommu_table_group *table_group,
+			int num,
+			__u32 page_shift,
+			__u64 window_size,
+			__u32 levels,
+			struct iommu_table *tbl);
+	long (*set_window)(struct iommu_table_group *table_group,
+			int num,
+			struct iommu_table *tblnew);
+	long (*unset_window)(struct iommu_table_group *table_group,
+			int num);
 };
 
 struct iommu_table_group {
 #ifdef CONFIG_IOMMU_API
 	struct iommu_group *group;
 #endif
+	/* Some key properties of IOMMU */
+	__u32 tce32_start;
+	__u32 tce32_size;
+	__u64 pgsizes; /* Bitmap of supported page sizes */
+	__u32 max_dynamic_windows_supported;
+	__u32 max_levels;
+
 	struct iommu_table tables[IOMMU_TABLE_GROUP_MAX_TABLES];
 	struct iommu_table_group_ops *ops;
 };
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index ca6c3f3..25a93f2 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -25,6 +25,7 @@
 #include <linux/memblock.h>
 #include <linux/iommu.h>
 #include <linux/mmzone.h>
+#include <linux/sizes.h>
 
 #include <asm/mmzone.h>
 #include <asm/sections.h>
@@ -48,6 +49,7 @@
 #include "pci.h"
 
 #define POWERNV_IOMMU_DEFAULT_LEVELS	1
+#define POWERNV_IOMMU_MAX_LEVELS	5
 
 static void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
 			    const char *fmt, ...)
@@ -1228,11 +1230,14 @@ static void pnv_ioda2_tce_free_vm(struct iommu_table *tbl, long index,
 		pnv_pci_ioda2_tce_invalidate(tbl, index, npages, false);
 }
 
+static void pnv_pci_free_table(struct iommu_table *tbl);
+
 static struct iommu_table_ops pnv_ioda2_iommu_ops = {
 	.set = pnv_ioda2_tce_build_vm,
 	.exchange = pnv_ioda2_tce_xchg_vm,
 	.clear = pnv_ioda2_tce_free_vm,
 	.get = pnv_tce_get,
+	.free = pnv_pci_free_table,
 };
 
 static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
@@ -1315,6 +1320,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 				 TCE_PCI_SWINV_PAIR);
 	}
 	tbl->it_ops = &pnv_ioda1_iommu_ops;
+	pe->table_group.tce32_start = tbl->it_offset << tbl->it_page_shift;
+	pe->table_group.tce32_size = tbl->it_size << tbl->it_page_shift;
 	iommu_init_table(tbl, phb->hose->node);
 	iommu_register_group(&pe->table_group, phb->hose->global_number,
 			pe->pe_number);
@@ -1399,7 +1406,7 @@ static __be64 *pnv_alloc_tce_table(int nid,
 }
 
 static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
-		__u32 page_shift, __u64 window_size, __u32 levels,
+		int num, __u32 page_shift, __u64 window_size, __u32 levels,
 		struct iommu_table *tbl)
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
@@ -1426,8 +1433,8 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
 	shift = ROUND_UP(ilog2(window_size) - page_shift, levels) / levels;
 	shift += 3;
 	shift = max_t(unsigned, shift, IOMMU_PAGE_SHIFT_4K);
-	pr_info("Creating TCE table %08llx, %d levels, TCE table size = %lx\n",
-			window_size, levels, 1UL << shift);
+	pr_info("Creating TCE table #%d %08llx, %d levels, TCE table size = %lx\n",
+			num, window_size, levels, 1UL << shift);
 
 	tbl->it_level_size = 1ULL << (shift - 3);
 	left = tce_table_size;
@@ -1438,8 +1445,8 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
 	tbl->it_indirect_levels = levels - 1;
 
 	/* Setup linux iommu table */
-	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, 0,
-			page_shift);
+	pnv_pci_setup_iommu_table(tbl, addr, tce_table_size,
+			num ? pe->tce_bypass_base : 0, page_shift);
 
 	tbl->it_ops = &pnv_ioda2_iommu_ops;
 
@@ -1458,8 +1465,21 @@ static void pnv_pci_free_table(struct iommu_table *tbl)
 	iommu_reset_table(tbl, "ioda2");
 }
 
+static inline void pnv_pci_ioda2_tvt_invalidate(unsigned int pe_number,
+		unsigned long it_index)
+{
+	__be64 __iomem *invalidate = (__be64 __iomem *)it_index;
+	/* 01xb - invalidate TCEs that match the specified PE# */
+	unsigned long addr = (0x4ull << 60) | (pe_number & 0xFF);
+
+	if (!it_index)
+		return;
+
+	__raw_writeq(cpu_to_be64(addr), invalidate);
+}
+
 static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
-		struct iommu_table *tbl)
+		int num, struct iommu_table *tbl)
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
 			table_group);
@@ -1471,13 +1491,13 @@ static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
 	const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
 	const __u64 win_size = tbl->it_size << tbl->it_page_shift;
 
-	pe_info(pe, "Setting up window at %llx..%llx pagesize=0x%x tablesize=0x%lx levels=%d levelsize=%x\n",
-			start_addr, start_addr + win_size - 1,
+	pe_info(pe, "Setting up window #%d (%p) at %llx..%llx pagesize=0x%x tablesize=0x%lx levels=%d levelsize=%x\n",
+			num, tbl, start_addr, start_addr + win_size - 1,
 			1UL << tbl->it_page_shift, tbl->it_size,
 			tbl->it_indirect_levels + 1, tbl->it_level_size);
 
-	pe->table_group.tables[0] = *tbl;
-	tbl = &pe->table_group.tables[0];
+	pe->table_group.tables[num] = *tbl;
+	tbl = &pe->table_group.tables[num];
 	tbl->it_group = &pe->table_group;
 
 	/*
@@ -1485,7 +1505,8 @@ static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
 	 * shifted by 1 bit for 32-bits DMA space.
 	 */
 	rc = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
-			pe->pe_number << 1, tbl->it_indirect_levels + 1,
+			(pe->pe_number << 1) + num,
+			tbl->it_indirect_levels + 1,
 			__pa(tbl->it_base),
 			size << 3, 1ULL << tbl->it_page_shift);
 	if (rc) {
@@ -1507,6 +1528,8 @@ static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
 		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
 	}
 
+	pnv_pci_ioda2_tvt_invalidate(pe->pe_number, tbl->it_index);
+
 	return 0;
 fail:
 	if (pe->tce32_seg >= 0)
@@ -1515,6 +1538,29 @@ fail:
 	return rc;
 }
 
+static long pnv_pci_ioda2_unset_window(struct iommu_table_group *table_group,
+		int num)
+{
+	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
+			table_group);
+	struct pnv_phb *phb = pe->phb;
+	long ret;
+
+	pe_info(pe, "Removing DMA window #%d\n", num);
+
+	ret = opal_pci_map_pe_dma_window(phb->opal_id, pe->pe_number,
+			(pe->pe_number << 1) + num,
+			0/* levels */, 0/* table address */,
+			0/* table size */, 0/* page size */);
+	if (ret)
+		pe_warn(pe, "Unmapping failed, ret = %ld\n", ret);
+
+	pnv_pci_ioda2_tvt_invalidate(pe->pe_number,
+			table_group->tables[num].it_index);
+
+	return ret;
+}
+
 static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
 {
 	uint16_t window_id = (pe->pe_number << 1 ) + 1;
@@ -1580,6 +1626,9 @@ static void pnv_ioda2_set_ownership(struct iommu_table_group *table_group,
 
 static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
 	.set_ownership = pnv_ioda2_set_ownership,
+	.create_table = pnv_pci_ioda2_create_table,
+	.set_window = pnv_pci_ioda2_set_window,
+	.unset_window = pnv_pci_ioda2_unset_window,
 };
 
 static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
@@ -1599,8 +1648,15 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	pe_info(pe, "Setting up 32-bit TCE table at 0..%08x\n",
 		end);
 
-	rc = pnv_pci_ioda2_create_table(&pe->table_group, IOMMU_PAGE_SHIFT_4K,
-			phb->ioda.m32_pci_base,
+	pe->table_group.tce32_start = 0;
+	pe->table_group.tce32_size = phb->ioda.m32_pci_base;
+	pe->table_group.max_dynamic_windows_supported =
+			IOMMU_TABLE_GROUP_MAX_TABLES;
+	pe->table_group.max_levels = POWERNV_IOMMU_MAX_LEVELS;
+	pe->table_group.pgsizes = SZ_4K | SZ_64K | SZ_16M;
+
+	rc = pnv_pci_ioda2_create_table(&pe->table_group, 0,
+			IOMMU_PAGE_SHIFT_4K, phb->ioda.m32_pci_base,
 			POWERNV_IOMMU_DEFAULT_LEVELS, tbl);
 	if (rc) {
 		pe_err(pe, "Failed to create 32-bit TCE table, err %ld", rc);
@@ -1612,7 +1668,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	iommu_init_table(tbl, phb->hose->node);
 	pe->table_group.ops = &pnv_pci_ioda2_ops;
 
-	rc = pnv_pci_ioda2_set_window(&pe->table_group, tbl);
+	rc = pnv_pci_ioda2_set_window(&pe->table_group, 0, tbl);
 	if (rc) {
 		pe_err(pe, "Failed to configure 32-bit TCE table,"
 		       " err %ld\n", rc);
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index 5888b2c..d309a5e 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -114,6 +114,8 @@ static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np, u64 hub_id,
 	u64 phb_id;
 	int64_t rc;
 	static int primary = 1;
+	struct iommu_table_group *table_group;
+	struct iommu_table *tbl;
 
 	pr_info(" Initializing p5ioc2 PHB %s\n", np->full_name);
 
@@ -178,13 +180,16 @@ static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np, u64 hub_id,
 	pnv_pci_init_p5ioc2_msis(phb);
 
 	/* Setup iommu */
-	phb->p5ioc2.table_group.tables[0].it_group = &phb->p5ioc2.table_group;
+	table_group = &phb->p5ioc2.table_group;
+	tbl = &phb->p5ioc2.table_group.tables[0];
+	tbl->it_group = table_group;
 
 	/* Setup TCEs */
 	phb->dma_dev_setup = pnv_pci_p5ioc2_dma_dev_setup;
-	pnv_pci_setup_iommu_table(&phb->p5ioc2.table_group.tables[0],
-				  tce_mem, tce_size, 0,
+	pnv_pci_setup_iommu_table(tbl, tce_mem, tce_size, 0,
 				  IOMMU_PAGE_SHIFT_4K);
+	table_group->tce32_start = tbl->it_offset << tbl->it_page_shift;
+	table_group->tce32_size = tbl->it_size << tbl->it_page_shift;
 }
 
 void __init pnv_pci_init_p5ioc2_hub(struct device_node *np)
-- 
2.0.0

[PATCH kernel v6 26/29] vfio: powerpc/spapr: Define v2 IOMMU

[Alexey Kardashevskiy]

The existing IOMMU requires VFIO_IOMMU_ENABLE call to enable actual use
of the container (i.e. call DMA map/unmap) and this is where we check
the rlimit for locked pages. It assumes that only as much memory
as a default DMA window can be mapped. Every DMA map/unmap request will
do pinning/unpinning of physical pages.

New IOMMU will split physical pages pinning and TCE table update.
It will require guest pages to be registered first and 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.
However when a huge DMA window is added, no additional pinning will be
required, otherwise it would be guest RAM + 2GB.

This advertises v2 SPAPR TCE IOMMU and restricts what the userspace
can do with v1 or v2 IOMMUs.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v6:
* enforced limitations imposed by the SPAPR TCE IOMMU version
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 18 +++++++++++++++++-
 include/uapi/linux/vfio.h           |  2 ++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 9d240b4..e191438 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -95,6 +95,7 @@ struct tce_container {
 	bool enabled;
 	unsigned long locked_pages;
 	struct list_head mem_list;
+	bool v2;
 };
 
 struct tce_memory {
@@ -398,7 +399,7 @@ 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);
 	}
@@ -410,6 +411,8 @@ static void *tce_iommu_open(unsigned long arg)
 	mutex_init(&container->lock);
 	INIT_LIST_HEAD_RCU(&container->mem_list);
 
+	container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
+
 	return container;
 }
 
@@ -580,6 +583,7 @@ 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:
@@ -719,6 +723,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 	case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
 		struct vfio_iommu_spapr_register_memory param;
 
+		if (!container->v2)
+			return -EPERM;
+
 		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
 				size);
 
@@ -741,6 +748,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 	case VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY: {
 		struct vfio_iommu_spapr_register_memory param;
 
+		if (!container->v2)
+			return -EPERM;
+
 		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
 				size);
 
@@ -761,6 +771,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 		return 0;
 	}
 	case VFIO_IOMMU_ENABLE:
+		if (container->v2)
+			return -EPERM;
+
 		mutex_lock(&container->lock);
 		ret = tce_iommu_enable(container);
 		mutex_unlock(&container->lock);
@@ -768,6 +781,9 @@ static long tce_iommu_ioctl(void *iommu_data,
 
 
 	case VFIO_IOMMU_DISABLE:
+		if (container->v2)
+			return -EPERM;
+
 		mutex_lock(&container->lock);
 		tce_iommu_disable(container);
 		mutex_unlock(&container->lock);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index b17e120..fbc5286 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
-- 
2.0.0

[PATCH kernel v6 27/29] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership

[Alexey Kardashevskiy]

Before the IOMMU user (VFIO) would take control over the IOMMU table
belonging to a specific IOMMU group. This approach did not allow sharing
tables between IOMMU groups attached to the same container.

This introduces a new IOMMU ownership flavour when the user can not
just control the existing IOMMU table but remove/create tables on demand.
If an IOMMU implements a set_ownership() callback, this lets the user have
full control over the IOMMU group. When the ownership is taken,
the platform code removes all the windows so the caller must create them.
Before returning the ownership back to the platform code, VFIO
unprograms and removes all the tables it created.

Old-style ownership is still supported allowing VFIO to run on older
P5IOC2 and IODA IO controllers.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v6:
* fixed commit log that VFIO removes tables before passing ownership
back to the platform code, not userspace
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 30 +++++++++++++++---
 drivers/vfio/vfio_iommu_spapr_tce.c       | 51 ++++++++++++++++++++++++-------
 2 files changed, 66 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 25a93f2..51394fb 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1616,11 +1616,33 @@ static void pnv_ioda2_set_ownership(struct iommu_table_group *table_group,
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,
 						table_group);
-	if (enable)
-		iommu_take_ownership(table_group);
-	else
-		iommu_release_ownership(table_group);
+	if (enable) {
+		pnv_pci_ioda2_unset_window(&pe->table_group, 0);
+		pnv_pci_free_table(&pe->table_group.tables[0]);
+	} else {
+		struct iommu_table *tbl = &pe->table_group.tables[0];
+		int64_t rc;
 
+		rc = pnv_pci_ioda2_create_table(&pe->table_group, 0,
+				IOMMU_PAGE_SHIFT_4K,
+				pe->phb->ioda.m32_pci_base,
+				POWERNV_IOMMU_DEFAULT_LEVELS, tbl);
+		if (rc) {
+			pe_err(pe, "Failed to create 32-bit TCE table, err %ld",
+					rc);
+			return;
+		}
+
+		iommu_init_table(tbl, pe->phb->hose->node);
+
+		rc = pnv_pci_ioda2_set_window(&pe->table_group, 0, tbl);
+		if (rc) {
+			pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
+					rc);
+			pnv_pci_free_table(tbl);
+			return;
+		}
+	}
 	pnv_pci_ioda2_set_bypass(pe, !enable);
 }
 
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index e191438..5e754b0 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -423,18 +423,11 @@ static int tce_iommu_clear(struct tce_container *container,
 static void tce_iommu_release(void *iommu_data)
 {
 	struct tce_container *container = iommu_data;
-	struct iommu_table *tbl;
-	struct iommu_table_group *table_group;
 
 	WARN_ON(container->grp);
 
-	if (container->grp) {
-		table_group = iommu_group_get_iommudata(container->grp);
-		tbl = &table_group->tables[0];
-		tce_iommu_clear(container, tbl,	tbl->it_offset, tbl->it_size);
-
+	if (container->grp)
 		tce_iommu_detach_group(iommu_data, container->grp);
-	}
 
 	tce_mem_unregister_all(container);
 	tce_iommu_disable(container);
@@ -833,14 +826,24 @@ static int tce_iommu_attach_group(void *iommu_data,
 
 	if (!table_group->ops || !table_group->ops->set_ownership) {
 		ret = iommu_take_ownership(table_group);
+	} else if (!table_group->ops->create_table ||
+			!table_group->ops->set_window) {
+		WARN_ON_ONCE(1);
+		ret = -EFAULT;
 	} else {
 		/*
 		 * Disable iommu bypass, otherwise the user can DMA to all of
 		 * our physical memory via the bypass window instead of just
 		 * the pages that has been explicitly mapped into the iommu
 		 */
+		struct iommu_table tbltmp = { 0 }, *tbl = &tbltmp;
+
 		table_group->ops->set_ownership(table_group, true);
-		ret = 0;
+		ret = table_group->ops->create_table(table_group, 0,
+				IOMMU_PAGE_SHIFT_4K,
+				table_group->tce32_size, 1, tbl);
+		if (!ret)
+			ret = table_group->ops->set_window(table_group, 0, tbl);
 	}
 
 	if (ret)
@@ -859,6 +862,7 @@ static void tce_iommu_detach_group(void *iommu_data,
 {
 	struct tce_container *container = iommu_data;
 	struct iommu_table_group *table_group;
+	long i;
 
 	mutex_lock(&container->lock);
 	if (iommu_group != container->grp) {
@@ -882,10 +886,35 @@ static void tce_iommu_detach_group(void *iommu_data,
 	BUG_ON(!table_group);
 
 	/* Kernel owns the device now, we can restore bypass */
-	if (!table_group->ops || !table_group->ops->set_ownership)
+	if (!table_group->ops || !table_group->ops->set_ownership) {
+		for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+			struct iommu_table *tbl = &table_group->tables[i];
+
+			if (!tbl->it_size)
+				continue;
+
+			if (!tbl->it_ops)
+				goto unlock_exit;
+			tce_iommu_clear(container, tbl,
+					tbl->it_offset, tbl->it_size);
+		}
 		iommu_release_ownership(table_group);
-	else
+	} else if (!table_group->ops->unset_window) {
+		WARN_ON_ONCE(1);
+	} else {
+		for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+			struct iommu_table *tbl = &table_group->tables[i];
+
+			table_group->ops->unset_window(table_group, i);
+			tce_iommu_clear(container, tbl,
+					tbl->it_offset, tbl->it_size);
+
+			if (tbl->it_ops->free)
+				tbl->it_ops->free(tbl);
+		}
+
 		table_group->ops->set_ownership(table_group, false);
+	}
 
 unlock_exit:
 
-- 
2.0.0

[PATCH kernel v6 28/29] vfio: powerpc/spapr: Support multiple groups in one container if possible

[Alexey Kardashevskiy]

At the moment only one group per container is supported.
POWER8 CPUs have more flexible design and allows naving 2 TCE tables per
IOMMU group so we can relax this limitation and support multiple groups
per container.

This adds TCE table descriptors to a container and uses iommu_table_group_ops
to create/set DMA windows on IOMMU groups so the same TCE tables will be
shared between several IOMMU groups.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 252 ++++++++++++++++++++++++------------
 1 file changed, 170 insertions(+), 82 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 5e754b0..d94116b 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -91,11 +91,17 @@ static void decrement_locked_vm(long npages)
  */
 struct tce_container {
 	struct mutex lock;
-	struct iommu_group *grp;
 	bool enabled;
 	unsigned long locked_pages;
 	struct list_head mem_list;
 	bool v2;
+	struct iommu_table tables[IOMMU_TABLE_GROUP_MAX_TABLES];
+	struct list_head group_list;
+};
+
+struct tce_iommu_group {
+	struct list_head next;
+	struct iommu_group *grp;
 };
 
 struct tce_memory {
@@ -295,20 +301,20 @@ 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 struct iommu_table *spapr_tce_find_table(
 		struct tce_container *container,
 		phys_addr_t ioba)
 {
 	long i;
 	struct iommu_table *ret = NULL;
-	struct iommu_table_group *table_group;
-
-	table_group = iommu_group_get_iommudata(container->grp);
-	if (!table_group)
-		return NULL;
 
 	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];
 		unsigned long entry = ioba >> tbl->it_page_shift;
 		unsigned long start = tbl->it_offset;
 		unsigned long end = start + tbl->it_size;
@@ -326,11 +332,8 @@ static int tce_iommu_enable(struct tce_container *container)
 {
 	int ret = 0;
 	unsigned long locked;
-	struct iommu_table *tbl;
 	struct iommu_table_group *table_group;
-
-	if (!container->grp)
-		return -ENXIO;
+	struct tce_iommu_group *tcegrp;
 
 	if (!current->mm)
 		return -ESRCH; /* process exited */
@@ -364,12 +367,24 @@ static int tce_iommu_enable(struct tce_container *container)
 	 * KVM agnostic.
 	 */
 	if (!tce_preregistered(container)) {
-		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;
 
-		tbl = &table_group->tables[0];
-		locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
+		/*
+		 * We do not allow enabling a group if no DMA-able memory was
+		 * registered as there is no way to know how much we should
+		 * increment the locked_vm counter.
+		 */
+		if (!table_group->tce32_size)
+			return -EPERM;
+
+		locked = table_group->tce32_size >> PAGE_SHIFT;
 		ret = try_increment_locked_vm(locked);
 		if (ret)
 			return ret;
@@ -410,6 +425,7 @@ static void *tce_iommu_open(unsigned long arg)
 
 	mutex_init(&container->lock);
 	INIT_LIST_HEAD_RCU(&container->mem_list);
+	INIT_LIST_HEAD_RCU(&container->group_list);
 
 	container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
 
@@ -423,11 +439,30 @@ static int tce_iommu_clear(struct tce_container *container,
 static void tce_iommu_release(void *iommu_data)
 {
 	struct tce_container *container = iommu_data;
+	struct iommu_table_group *table_group;
+	int i;
+	struct tce_iommu_group *tcegrp;
 
-	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);
+	/* Free tables */
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = &container->tables[i];
+
+		if (!tbl->it_size)
+			continue;
+
+		tce_iommu_clear(container, tbl,
+				tbl->it_offset, tbl->it_size);
+
+		if (tbl->it_ops && tbl->it_ops->free)
+			tbl->it_ops->free(tbl);
+	}
 
 	tce_mem_unregister_all(container);
 	tce_iommu_disable(container);
@@ -588,16 +623,17 @@ static long tce_iommu_ioctl(void *iommu_data,
 
 	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
 		struct vfio_iommu_spapr_tce_info info;
-		struct iommu_table *tbl;
+		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);
 
-		tbl = &table_group->tables[0];
-		if (WARN_ON_ONCE(!tbl))
+		if (!table_group)
 			return -ENXIO;
 
 		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
@@ -609,9 +645,8 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		info.dma32_window_start = tbl->it_offset << tbl->it_page_shift;
-		info.dma32_window_size = tbl->it_size << tbl->it_page_shift;
-		info.flags = 0;
+		info.dma32_window_start = table_group->tce32_start;
+		info.dma32_window_size = table_group->tce32_size;
 
 		if (copy_to_user((void __user *)arg, &info, minsz))
 			return -EFAULT;
@@ -781,12 +816,20 @@ static long tce_iommu_ioctl(void *iommu_data,
 		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;
@@ -795,63 +838,111 @@ static long tce_iommu_ioctl(void *iommu_data,
 static int tce_iommu_attach_group(void *iommu_data,
 		struct iommu_group *iommu_group)
 {
-	int ret;
+	int ret, i;
 	struct tce_container *container = iommu_data;
 	struct iommu_table_group *table_group;
+	struct tce_iommu_group *tcegrp = NULL;
+	bool first_group = !tce_groups_attached(container);
 
 	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 (!first_group && (!table_group->ops ||
+			!table_group->ops->set_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;
 	}
 
 	if (!table_group->ops || !table_group->ops->set_ownership) {
 		ret = iommu_take_ownership(table_group);
+		if (!ret)
+			container->tables[0] = table_group->tables[0];
 	} else if (!table_group->ops->create_table ||
 			!table_group->ops->set_window) {
 		WARN_ON_ONCE(1);
 		ret = -EFAULT;
 	} else {
-		/*
-		 * Disable iommu bypass, otherwise the user can DMA to all of
-		 * our physical memory via the bypass window instead of just
-		 * the pages that has been explicitly mapped into the iommu
-		 */
-		struct iommu_table tbltmp = { 0 }, *tbl = &tbltmp;
-
 		table_group->ops->set_ownership(table_group, true);
-		ret = table_group->ops->create_table(table_group, 0,
-				IOMMU_PAGE_SHIFT_4K,
-				table_group->tce32_size, 1, tbl);
-		if (!ret)
-			ret = table_group->ops->set_window(table_group, 0, tbl);
+		/*
+		 * If it the first group attached, check if there is any window
+		 * created and create one if none.
+		 */
+		if (first_group) {
+			bool found = false;
+
+			for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+				if (!container->tables[i].it_size)
+					continue;
+
+				found = true;
+				break;
+			}
+			if (!found) {
+				struct iommu_table *tbl = &container->tables[0];
+
+				ret = table_group->ops->create_table(
+						table_group, 0,
+						IOMMU_PAGE_SHIFT_4K,
+						table_group->tce32_size, 1,
+						tbl);
+				if (ret)
+					goto unlock_exit;
+			}
+		}
+
+		/* Set all windows to the new group */
+		for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+			struct iommu_table *tbl = &container->tables[i];
+
+			if (!tbl->it_size)
+				continue;
+
+			/* Set the default window to a new group */
+			ret = table_group->ops->set_window(table_group, i, tbl);
+			if (ret)
+				break;
+		}
 	}
 
 	if (ret)
 		goto unlock_exit;
 
-	container->grp = iommu_group;
+	tcegrp->grp = iommu_group;
+	list_add(&tcegrp->next, &container->group_list);
 
 unlock_exit:
+	if (ret && tcegrp)
+		kfree(tcegrp);
+
 	mutex_unlock(&container->lock);
 
 	return ret;
@@ -862,25 +953,27 @@ static void tce_iommu_detach_group(void *iommu_data,
 {
 	struct tce_container *container = iommu_data;
 	struct iommu_table_group *table_group;
+	struct tce_iommu_group *tcegrp, *tcetmp;
 	long i;
+	bool found = false;
 
 	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_safe(tcegrp, tcetmp, &container->group_list, next) {
+		if (tcegrp->grp != iommu_group)
+			continue;
+		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);
@@ -888,7 +981,7 @@ static void tce_iommu_detach_group(void *iommu_data,
 	/* Kernel owns the device now, we can restore bypass */
 	if (!table_group->ops || !table_group->ops->set_ownership) {
 		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->it_size)
 				continue;
@@ -897,20 +990,15 @@ static void tce_iommu_detach_group(void *iommu_data,
 				goto unlock_exit;
 			tce_iommu_clear(container, tbl,
 					tbl->it_offset, tbl->it_size);
+
+			memset(tbl, 0, sizeof(*tbl));
 		}
 		iommu_release_ownership(table_group);
 	} else if (!table_group->ops->unset_window) {
 		WARN_ON_ONCE(1);
 	} else {
 		for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
-			struct iommu_table *tbl = &table_group->tables[i];
-
 			table_group->ops->unset_window(table_group, i);
-			tce_iommu_clear(container, tbl,
-					tbl->it_offset, tbl->it_size);
-
-			if (tbl->it_ops->free)
-				tbl->it_ops->free(tbl);
 		}
 
 		table_group->ops->set_ownership(table_group, false);
-- 
2.0.0

[PATCH kernel v6 29/29] vfio: powerpc/spapr: Support Dynamic DMA windows

[Alexey Kardashevskiy]

This adds create/remove window ioctls to create and remove DMA windows.
sPAPR defines a Dynamic DMA windows capability which allows
para-virtualized guests to create additional DMA windows on a PCI bus.
The existing linux kernels use this new window to map the entire guest
memory and switch to the direct DMA operations saving time on map/unmap
requests which would normally happen in a big amounts.

This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and
VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows.
Up to 2 windows are supported now by the hardware and by this driver.

This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional
information such as a number of supported windows and maximum number
levels of TCE tables.

DDW is added as a capability, not as a SPAPR TCE IOMMU v2 unique feature
as we still want to support v2 on platforms which cannot do DDW for
the sake of TCE acceleration in KVM (coming soon).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v6:
* added explicit VFIO_IOMMU_INFO_DDW flag to vfio_iommu_spapr_tce_info,
it used to be page mask flags from platform code
* added explicit pgsizes field
* added cleanup if tce_iommu_create_window() failed in a middle
* added checks for callbacks in tce_iommu_create_window and remove those
from tce_iommu_remove_window when it is too late to test anyway
* spapr_tce_find_free_table returns sensible error code now
* updated description of VFIO_IOMMU_SPAPR_TCE_CREATE/
VFIO_IOMMU_SPAPR_TCE_REMOVE

v4:
* moved code to tce_iommu_create_window()/tce_iommu_remove_window()
helpers
* added docs
---
 Documentation/vfio.txt              |  19 ++++
 arch/powerpc/include/asm/iommu.h    |   2 +-
 drivers/vfio/vfio_iommu_spapr_tce.c | 206 +++++++++++++++++++++++++++++++++++-
 include/uapi/linux/vfio.h           |  41 ++++++-
 4 files changed, 265 insertions(+), 3 deletions(-)

diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
index 791e85c..61ce393 100644
--- a/Documentation/vfio.txt
+++ b/Documentation/vfio.txt
@@ -446,6 +446,25 @@ the memory block.
 The user space is not expected to call these often and the block descriptors
 are stored in a linked list in the kernel.
 
+6) sPAPR specification allows guests to have an ddditional DMA window(s) on
+a PCI bus with a variable page size. Two ioctls have been added to support
+this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE.
+The platform has to support the functionality or error will be returned to
+the userspace. The existing hardware supports up to 2 DMA windows, one is
+2GB long, uses 4K pages and called "default 32bit window"; the other can
+be as big as entire RAM, use different page size, it is optional - guests
+create those in run-time if the guest driver supports 64bit DMA.
+
+VFIO_IOMMU_SPAPR_TCE_CREATE receives a page shift, a DMA window size and
+a number of TCE table levels (if a TCE table is going to be big enough and
+the kernel may not be able to allocate enough of physicall contiguous memory).
+It creates a new window in the available slot and returns the bus address where
+the new window starts. Due to hardware limitation, the user space cannot choose
+the location of DMA windows.
+
+VFIO_IOMMU_SPAPR_TCE_REMOVE receives the bus start address of the window
+and removes it.
+
 -------------------------------------------------------------------------------
 
 [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 13145a2..bac02bf 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -138,7 +138,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
 extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
 					    int nid);
 
-#define IOMMU_TABLE_GROUP_MAX_TABLES	1
+#define IOMMU_TABLE_GROUP_MAX_TABLES	2
 
 struct iommu_table_group;
 
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index d94116b..0129a4f 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -600,11 +600,137 @@ static long tce_iommu_build(struct tce_container *container,
 	return ret;
 }
 
+static int spapr_tce_find_free_table(struct tce_container *container)
+{
+	int i;
+
+	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
+		struct iommu_table *tbl = &container->tables[i];
+
+		if (!tbl->it_size)
+			return i;
+	}
+
+	return -ENOSPC;
+}
+
+static long tce_iommu_create_window(struct tce_container *container,
+		__u32 page_shift, __u64 window_size, __u32 levels,
+		__u64 *start_addr)
+{
+	struct tce_iommu_group *tcegrp;
+	struct iommu_table_group *table_group;
+	struct iommu_table *tbl;
+	int num;
+	long ret;
+
+	num = spapr_tce_find_free_table(container);
+	if (num < 0)
+		return num;
+
+	tbl = &container->tables[num];
+
+	/* Get the first group for ops::create_table */
+	tcegrp = list_first_entry(&container->group_list,
+			struct tce_iommu_group, next);
+	table_group = iommu_group_get_iommudata(tcegrp->grp);
+	if (!table_group)
+		return -EFAULT;
+
+	if (!(table_group->pgsizes & (1ULL << page_shift)))
+		return -EINVAL;
+
+	if (!table_group->ops->set_window || !table_group->ops->unset_window ||
+			!table_group->ops->create_table)
+		return -EPERM;
+
+	/* Create TCE table */
+	ret = table_group->ops->create_table(table_group, num,
+			page_shift, window_size, levels, tbl);
+	if (ret)
+		return ret;
+
+	BUG_ON(!tbl->it_ops->free);
+
+	/*
+	 * Program the table to every group.
+	 * Groups have been tested for compatibility at the attach time.
+	 */
+	list_for_each_entry(tcegrp, &container->group_list, next) {
+		table_group = iommu_group_get_iommudata(tcegrp->grp);
+
+		ret = table_group->ops->set_window(table_group, num, tbl);
+		if (ret)
+			goto unset_exit;
+	}
+
+	/* Return start address assigned by platform in create_table() */
+	*start_addr = tbl->it_offset << tbl->it_page_shift;
+
+	return 0;
+
+unset_exit:
+	list_for_each_entry(tcegrp, &container->group_list, next) {
+		table_group = iommu_group_get_iommudata(tcegrp->grp);
+		table_group->ops->unset_window(table_group, num);
+	}
+	tbl->it_ops->free(tbl);
+	memset(tbl, 0, sizeof(*tbl));
+
+	return ret;
+}
+
+static long tce_iommu_remove_window(struct tce_container *container,
+		__u64 start_addr)
+{
+	struct iommu_table_group *table_group = NULL;
+	struct iommu_table *tbl;
+	struct tce_iommu_group *tcegrp;
+	int num;
+
+	tbl = spapr_tce_find_table(container, start_addr);
+	if (!tbl)
+		return -EINVAL;
+
+	/* Detach groups from IOMMUs */
+	num = tbl - container->tables;
+	list_for_each_entry(tcegrp, &container->group_list, next) {
+		table_group = iommu_group_get_iommudata(tcegrp->grp);
+
+		/*
+		 * When a group is attached, a window might be set if DDW
+		 * is supported by the platform. If it is not, VFIO will
+		 * use the existing window created by the platform code
+		 * so spapr_tce_find_table() will find a table but
+		 * since it is owned by the platform code, ops or unset_window()
+		 * will not be defined. If in this situation a broken
+		 * guest calls VFIO_IOMMU_SPAPR_TCE_REMOVE, we crash here
+		 * without the check.
+		 */
+		if (!table_group->ops || !table_group->ops->unset_window)
+			return -EPERM;
+
+		if (container->tables[num].it_size)
+			table_group->ops->unset_window(table_group, num);
+	}
+
+	/* Free table */
+	tcegrp = list_first_entry(&container->group_list,
+			struct tce_iommu_group, next);
+	table_group = iommu_group_get_iommudata(tcegrp->grp);
+
+	tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
+	tbl->it_ops->free(tbl);
+	memset(tbl, 0, sizeof(*tbl));
+
+	return 0;
+}
+
 static long tce_iommu_ioctl(void *iommu_data,
 				 unsigned int cmd, unsigned long arg)
 {
 	struct tce_container *container = iommu_data;
-	unsigned long minsz;
+	unsigned long minsz, ddwsz;
 	long ret;
 
 	switch (cmd) {
@@ -645,9 +771,24 @@ static long tce_iommu_ioctl(void *iommu_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
+		info.flags = 0;
 		info.dma32_window_start = table_group->tce32_start;
 		info.dma32_window_size = table_group->tce32_size;
 
+		if (table_group->max_dynamic_windows_supported) {
+			info.flags = VFIO_IOMMU_INFO_DDW;
+			info.pgsizes = table_group->pgsizes;
+			info.max_dynamic_windows_supported =
+				table_group->max_dynamic_windows_supported;
+			info.levels = table_group->max_levels;
+		}
+
+		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info,
+				levels);
+
+		if (info.argsz == ddwsz)
+			minsz = ddwsz;
+
 		if (copy_to_user((void __user *)arg, &info, minsz))
 			return -EFAULT;
 
@@ -830,6 +971,69 @@ static long tce_iommu_ioctl(void *iommu_data,
 		return ret;
 	}
 
+	case VFIO_IOMMU_SPAPR_TCE_CREATE: {
+		struct vfio_iommu_spapr_tce_create create;
+
+		if (!tce_preregistered(container))
+			return -EPERM;
+
+		if (!tce_groups_attached(container))
+			return -ENXIO;
+
+		minsz = offsetofend(struct vfio_iommu_spapr_tce_create,
+				start_addr);
+
+		if (copy_from_user(&create, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (create.argsz < minsz)
+			return -EINVAL;
+
+		if (create.flags)
+			return -EINVAL;
+
+		mutex_lock(&container->lock);
+
+		ret = tce_iommu_create_window(container, create.page_shift,
+				create.window_size, create.levels,
+				&create.start_addr);
+
+		if (!ret && copy_to_user((void __user *)arg, &create, minsz))
+			ret = -EFAULT;
+
+		mutex_unlock(&container->lock);
+
+		return ret;
+	}
+	case VFIO_IOMMU_SPAPR_TCE_REMOVE: {
+		struct vfio_iommu_spapr_tce_remove remove;
+
+		if (!tce_preregistered(container))
+			return -EPERM;
+
+		if (!tce_groups_attached(container))
+			return -ENXIO;
+
+		minsz = offsetofend(struct vfio_iommu_spapr_tce_remove,
+				start_addr);
+
+		if (copy_from_user(&remove, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (remove.argsz < minsz)
+			return -EINVAL;
+
+		if (remove.flags)
+			return -EINVAL;
+
+		mutex_lock(&container->lock);
+
+		ret = tce_iommu_remove_window(container, remove.start_addr);
+
+		mutex_unlock(&container->lock);
+
+		return ret;
+	}
 	}
 
 	return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index fbc5286..7fa02e1 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -457,9 +457,13 @@ struct vfio_iommu_type1_dma_unmap {
  */
 struct vfio_iommu_spapr_tce_info {
 	__u32 argsz;
-	__u32 flags;			/* reserved for future use */
+	__u32 flags;
+#define VFIO_IOMMU_INFO_DDW	(1 << 0)	/* DDW supported */
 	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
 	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
+	__u64 pgsizes;			/* Bitmap of supported page sizes */
+	__u32 max_dynamic_windows_supported;
+	__u32 levels;
 };
 
 #define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
@@ -520,6 +524,41 @@ struct vfio_iommu_spapr_register_memory {
  */
 #define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY	_IO(VFIO_TYPE, VFIO_BASE + 18)
 
+/**
+ * VFIO_IOMMU_SPAPR_TCE_CREATE - _IOWR(VFIO_TYPE, VFIO_BASE + 19, struct vfio_iommu_spapr_tce_create)
+ *
+ * Creates an additional TCE table and programs it (sets a new DMA window)
+ * to every IOMMU group in the container. It receives page shift, window
+ * size and number of levels in the TCE table being created.
+ *
+ * It allocates and returns an offset on a PCI bus of the new DMA window.
+ */
+struct vfio_iommu_spapr_tce_create {
+	__u32 argsz;
+	__u32 flags;
+	/* in */
+	__u32 page_shift;
+	__u64 window_size;
+	__u32 levels;
+	/* out */
+	__u64 start_addr;
+};
+#define VFIO_IOMMU_SPAPR_TCE_CREATE	_IO(VFIO_TYPE, VFIO_BASE + 19)
+
+/**
+ * VFIO_IOMMU_SPAPR_TCE_REMOVE - _IOW(VFIO_TYPE, VFIO_BASE + 20, struct vfio_iommu_spapr_tce_remove)
+ *
+ * Unprograms a TCE table from all groups in the container and destroys it.
+ * It receives a PCI bus offset as a window id.
+ */
+struct vfio_iommu_spapr_tce_remove {
+	__u32 argsz;
+	__u32 flags;
+	/* in */
+	__u64 start_addr;
+};
+#define VFIO_IOMMU_SPAPR_TCE_REMOVE	_IO(VFIO_TYPE, VFIO_BASE + 20)
+
 /* ***************************************************************** */
 
 #endif /* _UAPIVFIO_H */
-- 
2.0.0

Re: [PATCH kernel v6 29/29] vfio: powerpc/spapr: Support Dynamic DMA windows

[Alex Williamson]

On Fri, 2015-03-13 at 19:07 +1100, Alexey Kardashevskiy wrote:
> This adds create/remove window ioctls to create and remove DMA windows.
> sPAPR defines a Dynamic DMA windows capability which allows
> para-virtualized guests to create additional DMA windows on a PCI bus.
> The existing linux kernels use this new window to map the entire guest
> memory and switch to the direct DMA operations saving time on map/unmap
> requests which would normally happen in a big amounts.
> 
> This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and
> VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows.
> Up to 2 windows are supported now by the hardware and by this driver.
> 
> This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional
> information such as a number of supported windows and maximum number
> levels of TCE tables.
> 
> DDW is added as a capability, not as a SPAPR TCE IOMMU v2 unique feature
> as we still want to support v2 on platforms which cannot do DDW for
> the sake of TCE acceleration in KVM (coming soon).
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> Changes:
> v6:
> * added explicit VFIO_IOMMU_INFO_DDW flag to vfio_iommu_spapr_tce_info,
> it used to be page mask flags from platform code
> * added explicit pgsizes field
> * added cleanup if tce_iommu_create_window() failed in a middle
> * added checks for callbacks in tce_iommu_create_window and remove those
> from tce_iommu_remove_window when it is too late to test anyway
> * spapr_tce_find_free_table returns sensible error code now
> * updated description of VFIO_IOMMU_SPAPR_TCE_CREATE/
> VFIO_IOMMU_SPAPR_TCE_REMOVE
> 
> v4:
> * moved code to tce_iommu_create_window()/tce_iommu_remove_window()
> helpers
> * added docs
> ---
>  Documentation/vfio.txt              |  19 ++++
>  arch/powerpc/include/asm/iommu.h    |   2 +-
>  drivers/vfio/vfio_iommu_spapr_tce.c | 206 +++++++++++++++++++++++++++++++++++-
>  include/uapi/linux/vfio.h           |  41 ++++++-
>  4 files changed, 265 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
> index 791e85c..61ce393 100644
> --- a/Documentation/vfio.txt
> +++ b/Documentation/vfio.txt
> @@ -446,6 +446,25 @@ the memory block.
>  The user space is not expected to call these often and the block descriptors
>  are stored in a linked list in the kernel.
>  
> +6) sPAPR specification allows guests to have an ddditional DMA window(s) on


s/ddditional/additional/

> +a PCI bus with a variable page size. Two ioctls have been added to support
> +this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE.
> +The platform has to support the functionality or error will be returned to
> +the userspace. The existing hardware supports up to 2 DMA windows, one is
> +2GB long, uses 4K pages and called "default 32bit window"; the other can
> +be as big as entire RAM, use different page size, it is optional - guests
> +create those in run-time if the guest driver supports 64bit DMA.
> +
> +VFIO_IOMMU_SPAPR_TCE_CREATE receives a page shift, a DMA window size and
> +a number of TCE table levels (if a TCE table is going to be big enough and
> +the kernel may not be able to allocate enough of physicall contiguous memory).

s/physicall/physically/

> +It creates a new window in the available slot and returns the bus address where
> +the new window starts. Due to hardware limitation, the user space cannot choose
> +the location of DMA windows.
> +
> +VFIO_IOMMU_SPAPR_TCE_REMOVE receives the bus start address of the window
> +and removes it.
> +
>  -------------------------------------------------------------------------------
>  
>  [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 13145a2..bac02bf 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -138,7 +138,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
>  extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
>  					    int nid);
>  
> -#define IOMMU_TABLE_GROUP_MAX_TABLES	1
> +#define IOMMU_TABLE_GROUP_MAX_TABLES	2
>  
>  struct iommu_table_group;
>  
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index d94116b..0129a4f 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -600,11 +600,137 @@ static long tce_iommu_build(struct tce_container *container,
>  	return ret;
>  }
>  
> +static int spapr_tce_find_free_table(struct tce_container *container)
> +{
> +	int i;
> +
> +	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> +		struct iommu_table *tbl = &container->tables[i];
> +
> +		if (!tbl->it_size)
> +			return i;
> +	}
> +
> +	return -ENOSPC;
> +}
> +
> +static long tce_iommu_create_window(struct tce_container *container,
> +		__u32 page_shift, __u64 window_size, __u32 levels,
> +		__u64 *start_addr)
> +{
> +	struct tce_iommu_group *tcegrp;
> +	struct iommu_table_group *table_group;
> +	struct iommu_table *tbl;
> +	int num;
> +	long ret;
> +
> +	num = spapr_tce_find_free_table(container);
> +	if (num < 0)
> +		return num;
> +
> +	tbl = &container->tables[num];
> +
> +	/* Get the first group for ops::create_table */
> +	tcegrp = list_first_entry(&container->group_list,
> +			struct tce_iommu_group, next);
> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
> +	if (!table_group)
> +		return -EFAULT;
> +
> +	if (!(table_group->pgsizes & (1ULL << page_shift)))
> +		return -EINVAL;
> +
> +	if (!table_group->ops->set_window || !table_group->ops->unset_window ||
> +			!table_group->ops->create_table)
> +		return -EPERM;
> +
> +	/* Create TCE table */
> +	ret = table_group->ops->create_table(table_group, num,
> +			page_shift, window_size, levels, tbl);
> +	if (ret)
> +		return ret;
> +
> +	BUG_ON(!tbl->it_ops->free);
> +
> +	/*
> +	 * Program the table to every group.
> +	 * Groups have been tested for compatibility at the attach time.
> +	 */
> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> +
> +		ret = table_group->ops->set_window(table_group, num, tbl);
> +		if (ret)
> +			goto unset_exit;
> +	}
> +
> +	/* Return start address assigned by platform in create_table() */
> +	*start_addr = tbl->it_offset << tbl->it_page_shift;
> +
> +	return 0;
> +
> +unset_exit:
> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> +		table_group->ops->unset_window(table_group, num);
> +	}
> +	tbl->it_ops->free(tbl);
> +	memset(tbl, 0, sizeof(*tbl));
> +
> +	return ret;
> +}
> +
> +static long tce_iommu_remove_window(struct tce_container *container,
> +		__u64 start_addr)
> +{
> +	struct iommu_table_group *table_group = NULL;
> +	struct iommu_table *tbl;
> +	struct tce_iommu_group *tcegrp;
> +	int num;
> +
> +	tbl = spapr_tce_find_table(container, start_addr);
> +	if (!tbl)
> +		return -EINVAL;
> +
> +	/* Detach groups from IOMMUs */
> +	num = tbl - container->tables;
> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> +
> +		/*
> +		 * When a group is attached, a window might be set if DDW
> +		 * is supported by the platform. If it is not, VFIO will
> +		 * use the existing window created by the platform code
> +		 * so spapr_tce_find_table() will find a table but
> +		 * since it is owned by the platform code, ops or unset_window()
> +		 * will not be defined. If in this situation a broken
> +		 * guest calls VFIO_IOMMU_SPAPR_TCE_REMOVE, we crash here
> +		 * without the check.
> +		 */

Doesn't this indicate a more serious issue if a user can remove windows
that they didn't create?  It seems like that would open us to all sorts
of inconsistent state, if not exploits.

> +		if (!table_group->ops || !table_group->ops->unset_window)
> +			return -EPERM;
> +
> +		if (container->tables[num].it_size)
> +			table_group->ops->unset_window(table_group, num);
> +	}
> +
> +	/* Free table */
> +	tcegrp = list_first_entry(&container->group_list,
> +			struct tce_iommu_group, next);
> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
> +
> +	tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> +	tbl->it_ops->free(tbl);
> +	memset(tbl, 0, sizeof(*tbl));
> +
> +	return 0;
> +}
> +
>  static long tce_iommu_ioctl(void *iommu_data,
>  				 unsigned int cmd, unsigned long arg)
>  {
>  	struct tce_container *container = iommu_data;
> -	unsigned long minsz;
> +	unsigned long minsz, ddwsz;
>  	long ret;
>  
>  	switch (cmd) {
> @@ -645,9 +771,24 @@ static long tce_iommu_ioctl(void *iommu_data,
>  		if (info.argsz < minsz)
>  			return -EINVAL;
>  
> +		info.flags = 0;

This should not have been removed in the previous patch

>  		info.dma32_window_start = table_group->tce32_start;
>  		info.dma32_window_size = table_group->tce32_size;
>  
> +		if (table_group->max_dynamic_windows_supported) {
> +			info.flags = VFIO_IOMMU_INFO_DDW;

Shouldn't this be |= ?

> +			info.pgsizes = table_group->pgsizes;
> +			info.max_dynamic_windows_supported =
> +				table_group->max_dynamic_windows_supported;
> +			info.levels = table_group->max_levels;
> +		}
> +
> +		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info,
> +				levels);
> +
> +		if (info.argsz == ddwsz)
> +			minsz = ddwsz;
> +

How about >= ?  Requiring == means that a new userspace that might know
about a new field added to a later kernel will break on this kernel.

Also, if DDW is not supported, you're just about to write uninitialized
kernel data to userspace :-\

>  		if (copy_to_user((void __user *)arg, &info, minsz))
>  			return -EFAULT;
>  
> @@ -830,6 +971,69 @@ static long tce_iommu_ioctl(void *iommu_data,
>  		return ret;
>  	}
>  
> +	case VFIO_IOMMU_SPAPR_TCE_CREATE: {
> +		struct vfio_iommu_spapr_tce_create create;
> +
> +		if (!tce_preregistered(container))
> +			return -EPERM;
> +
> +		if (!tce_groups_attached(container))
> +			return -ENXIO;
> +
> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_create,
> +				start_addr);
> +
> +		if (copy_from_user(&create, (void __user *)arg, minsz))
> +			return -EFAULT;
> +
> +		if (create.argsz < minsz)
> +			return -EINVAL;
> +
> +		if (create.flags)
> +			return -EINVAL;
> +
> +		mutex_lock(&container->lock);
> +
> +		ret = tce_iommu_create_window(container, create.page_shift,
> +				create.window_size, create.levels,
> +				&create.start_addr);
> +
> +		if (!ret && copy_to_user((void __user *)arg, &create, minsz))
> +			ret = -EFAULT;
> +
> +		mutex_unlock(&container->lock);

Even easier would be to move the unlock up, we probably don't need to
protect the copy_to_user().

> +
> +		return ret;
> +	}
> +	case VFIO_IOMMU_SPAPR_TCE_REMOVE: {
> +		struct vfio_iommu_spapr_tce_remove remove;
> +
> +		if (!tce_preregistered(container))
> +			return -EPERM;
> +
> +		if (!tce_groups_attached(container))
> +			return -ENXIO;
> +
> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_remove,
> +				start_addr);
> +
> +		if (copy_from_user(&remove, (void __user *)arg, minsz))
> +			return -EFAULT;
> +
> +		if (remove.argsz < minsz)
> +			return -EINVAL;
> +
> +		if (remove.flags)
> +			return -EINVAL;
> +
> +		mutex_lock(&container->lock);
> +
> +		ret = tce_iommu_remove_window(container, remove.start_addr);
> +
> +		mutex_unlock(&container->lock);
> +
> +		return ret;
> +	}
>  	}
>  
>  	return -ENOTTY;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index fbc5286..7fa02e1 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -457,9 +457,13 @@ struct vfio_iommu_type1_dma_unmap {
>   */
>  struct vfio_iommu_spapr_tce_info {
>  	__u32 argsz;
> -	__u32 flags;			/* reserved for future use */
> +	__u32 flags;
> +#define VFIO_IOMMU_INFO_DDW	(1 << 0)	/* DDW supported */

s/VFIO_IOMMU_INFO_DDW/VFIO_IOMMU_SPAPR_INFO_DDW/

>  	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
>  	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
> +	__u64 pgsizes;			/* Bitmap of supported page sizes */
> +	__u32 max_dynamic_windows_supported;
> +	__u32 levels;

Please indicate that the last 3 fields are only supported with DDW.

>  };
>  
>  #define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
> @@ -520,6 +524,41 @@ struct vfio_iommu_spapr_register_memory {
>   */
>  #define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY	_IO(VFIO_TYPE, VFIO_BASE + 18)
>  
> +/**
> + * VFIO_IOMMU_SPAPR_TCE_CREATE - _IOWR(VFIO_TYPE, VFIO_BASE + 19, struct vfio_iommu_spapr_tce_create)
> + *
> + * Creates an additional TCE table and programs it (sets a new DMA window)
> + * to every IOMMU group in the container. It receives page shift, window
> + * size and number of levels in the TCE table being created.
> + *
> + * It allocates and returns an offset on a PCI bus of the new DMA window.
> + */
> +struct vfio_iommu_spapr_tce_create {
> +	__u32 argsz;
> +	__u32 flags;
> +	/* in */
> +	__u32 page_shift;
> +	__u64 window_size;
> +	__u32 levels;
> +	/* out */
> +	__u64 start_addr;
> +};
> +#define VFIO_IOMMU_SPAPR_TCE_CREATE	_IO(VFIO_TYPE, VFIO_BASE + 19)
> +
> +/**
> + * VFIO_IOMMU_SPAPR_TCE_REMOVE - _IOW(VFIO_TYPE, VFIO_BASE + 20, struct vfio_iommu_spapr_tce_remove)
> + *
> + * Unprograms a TCE table from all groups in the container and destroys it.
> + * It receives a PCI bus offset as a window id.
> + */
> +struct vfio_iommu_spapr_tce_remove {
> +	__u32 argsz;
> +	__u32 flags;
> +	/* in */
> +	__u64 start_addr;
> +};
> +#define VFIO_IOMMU_SPAPR_TCE_REMOVE	_IO(VFIO_TYPE, VFIO_BASE + 20)
> +
>  /* ***************************************************************** */
>  
>  #endif /* _UAPIVFIO_H */

Re: [PATCH kernel v6 26/29] vfio: powerpc/spapr: Define v2 IOMMU

[Alex Williamson]

On Fri, 2015-03-13 at 19:07 +1100, Alexey Kardashevskiy wrote:
> The existing IOMMU requires VFIO_IOMMU_ENABLE call to enable actual use
> of the container (i.e. call DMA map/unmap) and this is where we check
> the rlimit for locked pages. It assumes that only as much memory
> as a default DMA window can be mapped. Every DMA map/unmap request will
> do pinning/unpinning of physical pages.
> 
> New IOMMU will split physical pages pinning and TCE table update.
> It will require guest pages to be registered first and 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.
> However when a huge DMA window is added, no additional pinning will be
> required, otherwise it would be guest RAM + 2GB.
> 
> This advertises v2 SPAPR TCE IOMMU and restricts what the userspace
> can do with v1 or v2 IOMMUs.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> Changes:
> v6:
> * enforced limitations imposed by the SPAPR TCE IOMMU version
> ---
>  drivers/vfio/vfio_iommu_spapr_tce.c | 18 +++++++++++++++++-
>  include/uapi/linux/vfio.h           |  2 ++
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 9d240b4..e191438 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -95,6 +95,7 @@ struct tce_container {
>  	bool enabled;
>  	unsigned long locked_pages;
>  	struct list_head mem_list;
> +	bool v2;
>  };
>  
>  struct tce_memory {
> @@ -398,7 +399,7 @@ 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);
>  	}
> @@ -410,6 +411,8 @@ static void *tce_iommu_open(unsigned long arg)
>  	mutex_init(&container->lock);
>  	INIT_LIST_HEAD_RCU(&container->mem_list);
>  
> +	container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
> +
>  	return container;
>  }
>  
> @@ -580,6 +583,7 @@ 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:
> @@ -719,6 +723,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>  	case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
>  		struct vfio_iommu_spapr_register_memory param;
>  
> +		if (!container->v2)
> +			return -EPERM;
> +
>  		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
>  				size);
>  
> @@ -741,6 +748,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>  	case VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY: {
>  		struct vfio_iommu_spapr_register_memory param;
>  
> +		if (!container->v2)
> +			return -EPERM;
> +
>  		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
>  				size);
>  
> @@ -761,6 +771,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>  		return 0;
>  	}
>  	case VFIO_IOMMU_ENABLE:
> +		if (container->v2)
> +			return -EPERM;
> +
>  		mutex_lock(&container->lock);
>  		ret = tce_iommu_enable(container);
>  		mutex_unlock(&container->lock);
> @@ -768,6 +781,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>  
> 
>  	case VFIO_IOMMU_DISABLE:
> +		if (container->v2)
> +			return -EPERM;
> +
>  		mutex_lock(&container->lock);
>  		tce_iommu_disable(container);
>  		mutex_unlock(&container->lock);


I wouldn't have guessed; nothing in the documentation suggests these
ioctls are deprecated in v2 (ie. please document).  If the ioctl doesn't
exist for the IOMMU type, why not simply break and let it fall out at
-ENOTTY?  Same for the above, v1 would have previously returned -ENOTTY
for those ioctls, why change to -EPERM?


> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index b17e120..fbc5286 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

Re: [PATCH kernel v6 29/29] vfio: powerpc/spapr: Support Dynamic DMA windows

[Alexey Kardashevskiy]

On 03/17/2015 06:38 AM, Alex Williamson wrote:
> On Fri, 2015-03-13 at 19:07 +1100, Alexey Kardashevskiy wrote:
>> This adds create/remove window ioctls to create and remove DMA windows.
>> sPAPR defines a Dynamic DMA windows capability which allows
>> para-virtualized guests to create additional DMA windows on a PCI bus.
>> The existing linux kernels use this new window to map the entire guest
>> memory and switch to the direct DMA operations saving time on map/unmap
>> requests which would normally happen in a big amounts.
>>
>> This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and
>> VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows.
>> Up to 2 windows are supported now by the hardware and by this driver.
>>
>> This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional
>> information such as a number of supported windows and maximum number
>> levels of TCE tables.
>>
>> DDW is added as a capability, not as a SPAPR TCE IOMMU v2 unique feature
>> as we still want to support v2 on platforms which cannot do DDW for
>> the sake of TCE acceleration in KVM (coming soon).
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> Changes:
>> v6:
>> * added explicit VFIO_IOMMU_INFO_DDW flag to vfio_iommu_spapr_tce_info,
>> it used to be page mask flags from platform code
>> * added explicit pgsizes field
>> * added cleanup if tce_iommu_create_window() failed in a middle
>> * added checks for callbacks in tce_iommu_create_window and remove those
>> from tce_iommu_remove_window when it is too late to test anyway
>> * spapr_tce_find_free_table returns sensible error code now
>> * updated description of VFIO_IOMMU_SPAPR_TCE_CREATE/
>> VFIO_IOMMU_SPAPR_TCE_REMOVE
>>
>> v4:
>> * moved code to tce_iommu_create_window()/tce_iommu_remove_window()
>> helpers
>> * added docs
>> ---
>>   Documentation/vfio.txt              |  19 ++++
>>   arch/powerpc/include/asm/iommu.h    |   2 +-
>>   drivers/vfio/vfio_iommu_spapr_tce.c | 206 +++++++++++++++++++++++++++++++++++-
>>   include/uapi/linux/vfio.h           |  41 ++++++-
>>   4 files changed, 265 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
>> index 791e85c..61ce393 100644
>> --- a/Documentation/vfio.txt
>> +++ b/Documentation/vfio.txt
>> @@ -446,6 +446,25 @@ the memory block.
>>   The user space is not expected to call these often and the block descriptors
>>   are stored in a linked list in the kernel.
>>
>> +6) sPAPR specification allows guests to have an ddditional DMA window(s) on
>
>
> s/ddditional/additional/
>
>> +a PCI bus with a variable page size. Two ioctls have been added to support
>> +this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE.
>> +The platform has to support the functionality or error will be returned to
>> +the userspace. The existing hardware supports up to 2 DMA windows, one is
>> +2GB long, uses 4K pages and called "default 32bit window"; the other can
>> +be as big as entire RAM, use different page size, it is optional - guests
>> +create those in run-time if the guest driver supports 64bit DMA.
>> +
>> +VFIO_IOMMU_SPAPR_TCE_CREATE receives a page shift, a DMA window size and
>> +a number of TCE table levels (if a TCE table is going to be big enough and
>> +the kernel may not be able to allocate enough of physicall contiguous memory).
>
> s/physicall/physically/
>
>> +It creates a new window in the available slot and returns the bus address where
>> +the new window starts. Due to hardware limitation, the user space cannot choose
>> +the location of DMA windows.
>> +
>> +VFIO_IOMMU_SPAPR_TCE_REMOVE receives the bus start address of the window
>> +and removes it.
>> +
>>   -------------------------------------------------------------------------------
>>
>>   [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 13145a2..bac02bf 100644
>> --- a/arch/powerpc/include/asm/iommu.h
>> +++ b/arch/powerpc/include/asm/iommu.h
>> @@ -138,7 +138,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
>>   extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
>>   					    int nid);
>>
>> -#define IOMMU_TABLE_GROUP_MAX_TABLES	1
>> +#define IOMMU_TABLE_GROUP_MAX_TABLES	2
>>
>>   struct iommu_table_group;
>>
>> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
>> index d94116b..0129a4f 100644
>> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
>> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
>> @@ -600,11 +600,137 @@ static long tce_iommu_build(struct tce_container *container,
>>   	return ret;
>>   }
>>
>> +static int spapr_tce_find_free_table(struct tce_container *container)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
>> +		struct iommu_table *tbl = &container->tables[i];
>> +
>> +		if (!tbl->it_size)
>> +			return i;
>> +	}
>> +
>> +	return -ENOSPC;
>> +}
>> +
>> +static long tce_iommu_create_window(struct tce_container *container,
>> +		__u32 page_shift, __u64 window_size, __u32 levels,
>> +		__u64 *start_addr)
>> +{
>> +	struct tce_iommu_group *tcegrp;
>> +	struct iommu_table_group *table_group;
>> +	struct iommu_table *tbl;
>> +	int num;
>> +	long ret;
>> +
>> +	num = spapr_tce_find_free_table(container);
>> +	if (num < 0)
>> +		return num;
>> +
>> +	tbl = &container->tables[num];
>> +
>> +	/* Get the first group for ops::create_table */
>> +	tcegrp = list_first_entry(&container->group_list,
>> +			struct tce_iommu_group, next);
>> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
>> +	if (!table_group)
>> +		return -EFAULT;
>> +
>> +	if (!(table_group->pgsizes & (1ULL << page_shift)))
>> +		return -EINVAL;
>> +
>> +	if (!table_group->ops->set_window || !table_group->ops->unset_window ||
>> +			!table_group->ops->create_table)
>> +		return -EPERM;
>> +
>> +	/* Create TCE table */
>> +	ret = table_group->ops->create_table(table_group, num,
>> +			page_shift, window_size, levels, tbl);
>> +	if (ret)
>> +		return ret;
>> +
>> +	BUG_ON(!tbl->it_ops->free);
>> +
>> +	/*
>> +	 * Program the table to every group.
>> +	 * Groups have been tested for compatibility at the attach time.
>> +	 */
>> +	list_for_each_entry(tcegrp, &container->group_list, next) {
>> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
>> +
>> +		ret = table_group->ops->set_window(table_group, num, tbl);
>> +		if (ret)
>> +			goto unset_exit;
>> +	}
>> +
>> +	/* Return start address assigned by platform in create_table() */
>> +	*start_addr = tbl->it_offset << tbl->it_page_shift;
>> +
>> +	return 0;
>> +
>> +unset_exit:
>> +	list_for_each_entry(tcegrp, &container->group_list, next) {
>> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
>> +		table_group->ops->unset_window(table_group, num);
>> +	}
>> +	tbl->it_ops->free(tbl);
>> +	memset(tbl, 0, sizeof(*tbl));
>> +
>> +	return ret;
>> +}
>> +
>> +static long tce_iommu_remove_window(struct tce_container *container,
>> +		__u64 start_addr)
>> +{
>> +	struct iommu_table_group *table_group = NULL;
>> +	struct iommu_table *tbl;
>> +	struct tce_iommu_group *tcegrp;
>> +	int num;
>> +
>> +	tbl = spapr_tce_find_table(container, start_addr);
>> +	if (!tbl)
>> +		return -EINVAL;
>> +
>> +	/* Detach groups from IOMMUs */
>> +	num = tbl - container->tables;
>> +	list_for_each_entry(tcegrp, &container->group_list, next) {
>> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
>> +
>> +		/*
>> +		 * When a group is attached, a window might be set if DDW
>> +		 * is supported by the platform. If it is not, VFIO will
>> +		 * use the existing window created by the platform code
>> +		 * so spapr_tce_find_table() will find a table but
>> +		 * since it is owned by the platform code, ops or unset_window()
>> +		 * will not be defined. If in this situation a broken
>> +		 * guest calls VFIO_IOMMU_SPAPR_TCE_REMOVE, we crash here
>> +		 * without the check.
>> +		 */
>
> Doesn't this indicate a more serious issue if a user can remove windows
> that they didn't create?  It seems like that would open us to all sorts
 > of inconsistent state, if not exploits.


The existing upstream QEMU expects the default window to exits. So there is 
at least one situation when there is a window which the user did not create.

1. A window can be owned by the "powernv" platform or VFIO. If it is 
"powernv" (old power7 IO chips) - removal of a window is not enabled, 
otherwise (new power8 chip) it is.

2. Old QEMU expects the default window to exist. If it is "powernv" owned 
window, then VFIO just reuses it, otherwise it creates one.

What is inconsistent about the state? Or I just document it in 
Documentation/vfio.txt and that's it?

>
>> +		if (!table_group->ops || !table_group->ops->unset_window)
>> +			return -EPERM;
>> +
>> +		if (container->tables[num].it_size)
>> +			table_group->ops->unset_window(table_group, num);
>> +	}
>> +
>> +	/* Free table */
>> +	tcegrp = list_first_entry(&container->group_list,
>> +			struct tce_iommu_group, next);
>> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
>> +
>> +	tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
>> +	tbl->it_ops->free(tbl);
>> +	memset(tbl, 0, sizeof(*tbl));
>> +
>> +	return 0;
>> +}
>> +
>>   static long tce_iommu_ioctl(void *iommu_data,
>>   				 unsigned int cmd, unsigned long arg)
>>   {
>>   	struct tce_container *container = iommu_data;
>> -	unsigned long minsz;
>> +	unsigned long minsz, ddwsz;
>>   	long ret;
>>
>>   	switch (cmd) {
>> @@ -645,9 +771,24 @@ static long tce_iommu_ioctl(void *iommu_data,
>>   		if (info.argsz < minsz)
>>   			return -EINVAL;
>>
>> +		info.flags = 0;
>
> This should not have been removed in the previous patch

Ouch. Multiple rebase result :)


>>   		info.dma32_window_start = table_group->tce32_start;
>>   		info.dma32_window_size = table_group->tce32_size;
>>
>> +		if (table_group->max_dynamic_windows_supported) {
>> +			info.flags = VFIO_IOMMU_INFO_DDW;
>
> Shouldn't this be |= ?
>
>> +			info.pgsizes = table_group->pgsizes;
>> +			info.max_dynamic_windows_supported =
>> +				table_group->max_dynamic_windows_supported;
>> +			info.levels = table_group->max_levels;
>> +		}
>> +
>> +		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info,
>> +				levels);
>> +
>> +		if (info.argsz == ddwsz)
>> +			minsz = ddwsz;
>> +
>
> How about >= ?  Requiring == means that a new userspace that might know
> about a new field added to a later kernel will break on this kernel.
>
> Also, if DDW is not supported, you're just about to write uninitialized
> kernel data to userspace :-\
>
>>   		if (copy_to_user((void __user *)arg, &info, minsz))


then copy_to_user(..., info.argsz) is the answer, no? I do not really want 
to touch the area of the struct I do not support in this call, unless there 
is some code guideline for ioctl implementation.


>>   			return -EFAULT;
>>
>> @@ -830,6 +971,69 @@ static long tce_iommu_ioctl(void *iommu_data,
>>   		return ret;
>>   	}
>>
>> +	case VFIO_IOMMU_SPAPR_TCE_CREATE: {
>> +		struct vfio_iommu_spapr_tce_create create;
>> +
>> +		if (!tce_preregistered(container))
>> +			return -EPERM;
>> +
>> +		if (!tce_groups_attached(container))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_create,
>> +				start_addr);
>> +
>> +		if (copy_from_user(&create, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (create.argsz < minsz)
>> +			return -EINVAL;
>> +
>> +		if (create.flags)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&container->lock);
>> +
>> +		ret = tce_iommu_create_window(container, create.page_shift,
>> +				create.window_size, create.levels,
>> +				&create.start_addr);
>> +
>> +		if (!ret && copy_to_user((void __user *)arg, &create, minsz))
>> +			ret = -EFAULT;
>> +
>> +		mutex_unlock(&container->lock);
>
> Even easier would be to move the unlock up, we probably don't need to
> protect the copy_to_user().
 >
>> +
>> +		return ret;
>> +	}
>> +	case VFIO_IOMMU_SPAPR_TCE_REMOVE: {
>> +		struct vfio_iommu_spapr_tce_remove remove;
>> +
>> +		if (!tce_preregistered(container))
>> +			return -EPERM;
>> +
>> +		if (!tce_groups_attached(container))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_remove,
>> +				start_addr);
>> +
>> +		if (copy_from_user(&remove, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (remove.argsz < minsz)
>> +			return -EINVAL;
>> +
>> +		if (remove.flags)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&container->lock);
>> +
>> +		ret = tce_iommu_remove_window(container, remove.start_addr);
>> +
>> +		mutex_unlock(&container->lock);
>> +
>> +		return ret;
>> +	}
>>   	}
>>
>>   	return -ENOTTY;
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index fbc5286..7fa02e1 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -457,9 +457,13 @@ struct vfio_iommu_type1_dma_unmap {
>>    */
>>   struct vfio_iommu_spapr_tce_info {
>>   	__u32 argsz;
>> -	__u32 flags;			/* reserved for future use */
>> +	__u32 flags;
>> +#define VFIO_IOMMU_INFO_DDW	(1 << 0)	/* DDW supported */
>
> s/VFIO_IOMMU_INFO_DDW/VFIO_IOMMU_SPAPR_INFO_DDW/

VFIO_IOMMU_INFO_PGSIZES is not VFIO_IOMMU_TYPE1_INFO_PGSIZES ;-) but I'll fix.


>
>>   	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
>>   	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
>> +	__u64 pgsizes;			/* Bitmap of supported page sizes */
>> +	__u32 max_dynamic_windows_supported;
>> +	__u32 levels;
>
> Please indicate that the last 3 fields are only supported with DDW.


Like this?

===
- * A flag will need to be added if other page sizes are supported,
- * so as defined here, it is always 4k.
+ * Flags supported:
+ * - VFIO_IOMMU_INFO_DDW: informs the userspace that dynamic DMA windows
+ *   (DDW) support is present. @pgsizes, @max_dynamic_windows_supported,
+ *   @levels are only supported when DDW is present.
   */
  struct vfio_iommu_spapr_tce_info {
         __u32 argsz;

===


>
>>   };
>>
>>   #define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
>> @@ -520,6 +524,41 @@ struct vfio_iommu_spapr_register_memory {
>>    */
>>   #define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY	_IO(VFIO_TYPE, VFIO_BASE + 18)
>>
>> +/**
>> + * VFIO_IOMMU_SPAPR_TCE_CREATE - _IOWR(VFIO_TYPE, VFIO_BASE + 19, struct vfio_iommu_spapr_tce_create)
>> + *
>> + * Creates an additional TCE table and programs it (sets a new DMA window)
>> + * to every IOMMU group in the container. It receives page shift, window
>> + * size and number of levels in the TCE table being created.
>> + *
>> + * It allocates and returns an offset on a PCI bus of the new DMA window.
>> + */
>> +struct vfio_iommu_spapr_tce_create {
>> +	__u32 argsz;
>> +	__u32 flags;
>> +	/* in */
>> +	__u32 page_shift;
>> +	__u64 window_size;
>> +	__u32 levels;
>> +	/* out */
>> +	__u64 start_addr;
>> +};
>> +#define VFIO_IOMMU_SPAPR_TCE_CREATE	_IO(VFIO_TYPE, VFIO_BASE + 19)
>> +
>> +/**
>> + * VFIO_IOMMU_SPAPR_TCE_REMOVE - _IOW(VFIO_TYPE, VFIO_BASE + 20, struct vfio_iommu_spapr_tce_remove)
>> + *
>> + * Unprograms a TCE table from all groups in the container and destroys it.
>> + * It receives a PCI bus offset as a window id.
>> + */
>> +struct vfio_iommu_spapr_tce_remove {
>> +	__u32 argsz;
>> +	__u32 flags;
>> +	/* in */
>> +	__u64 start_addr;
>> +};
>> +#define VFIO_IOMMU_SPAPR_TCE_REMOVE	_IO(VFIO_TYPE, VFIO_BASE + 20)
>> +
>>   /* ***************************************************************** */
>>
>>   #endif /* _UAPIVFIO_H */
>
>
>


-- 
Alexey

Re: [PATCH kernel v6 29/29] vfio: powerpc/spapr: Support Dynamic DMA windows

[Alex Williamson]

On Tue, 2015-03-17 at 12:02 +1100, Alexey Kardashevskiy wrote:
> On 03/17/2015 06:38 AM, Alex Williamson wrote:
> > On Fri, 2015-03-13 at 19:07 +1100, Alexey Kardashevskiy wrote:
> >> This adds create/remove window ioctls to create and remove DMA windows.
> >> sPAPR defines a Dynamic DMA windows capability which allows
> >> para-virtualized guests to create additional DMA windows on a PCI bus.
> >> The existing linux kernels use this new window to map the entire guest
> >> memory and switch to the direct DMA operations saving time on map/unmap
> >> requests which would normally happen in a big amounts.
> >>
> >> This adds 2 ioctl handlers - VFIO_IOMMU_SPAPR_TCE_CREATE and
> >> VFIO_IOMMU_SPAPR_TCE_REMOVE - to create and remove windows.
> >> Up to 2 windows are supported now by the hardware and by this driver.
> >>
> >> This changes VFIO_IOMMU_SPAPR_TCE_GET_INFO handler to return additional
> >> information such as a number of supported windows and maximum number
> >> levels of TCE tables.
> >>
> >> DDW is added as a capability, not as a SPAPR TCE IOMMU v2 unique feature
> >> as we still want to support v2 on platforms which cannot do DDW for
> >> the sake of TCE acceleration in KVM (coming soon).
> >>
> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> >> ---
> >> Changes:
> >> v6:
> >> * added explicit VFIO_IOMMU_INFO_DDW flag to vfio_iommu_spapr_tce_info,
> >> it used to be page mask flags from platform code
> >> * added explicit pgsizes field
> >> * added cleanup if tce_iommu_create_window() failed in a middle
> >> * added checks for callbacks in tce_iommu_create_window and remove those
> >> from tce_iommu_remove_window when it is too late to test anyway
> >> * spapr_tce_find_free_table returns sensible error code now
> >> * updated description of VFIO_IOMMU_SPAPR_TCE_CREATE/
> >> VFIO_IOMMU_SPAPR_TCE_REMOVE
> >>
> >> v4:
> >> * moved code to tce_iommu_create_window()/tce_iommu_remove_window()
> >> helpers
> >> * added docs
> >> ---
> >>   Documentation/vfio.txt              |  19 ++++
> >>   arch/powerpc/include/asm/iommu.h    |   2 +-
> >>   drivers/vfio/vfio_iommu_spapr_tce.c | 206 +++++++++++++++++++++++++++++++++++-
> >>   include/uapi/linux/vfio.h           |  41 ++++++-
> >>   4 files changed, 265 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
> >> index 791e85c..61ce393 100644
> >> --- a/Documentation/vfio.txt
> >> +++ b/Documentation/vfio.txt
> >> @@ -446,6 +446,25 @@ the memory block.
> >>   The user space is not expected to call these often and the block descriptors
> >>   are stored in a linked list in the kernel.
> >>
> >> +6) sPAPR specification allows guests to have an ddditional DMA window(s) on
> >
> >
> > s/ddditional/additional/
> >
> >> +a PCI bus with a variable page size. Two ioctls have been added to support
> >> +this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE.
> >> +The platform has to support the functionality or error will be returned to
> >> +the userspace. The existing hardware supports up to 2 DMA windows, one is
> >> +2GB long, uses 4K pages and called "default 32bit window"; the other can
> >> +be as big as entire RAM, use different page size, it is optional - guests
> >> +create those in run-time if the guest driver supports 64bit DMA.
> >> +
> >> +VFIO_IOMMU_SPAPR_TCE_CREATE receives a page shift, a DMA window size and
> >> +a number of TCE table levels (if a TCE table is going to be big enough and
> >> +the kernel may not be able to allocate enough of physicall contiguous memory).
> >
> > s/physicall/physically/
> >
> >> +It creates a new window in the available slot and returns the bus address where
> >> +the new window starts. Due to hardware limitation, the user space cannot choose
> >> +the location of DMA windows.
> >> +
> >> +VFIO_IOMMU_SPAPR_TCE_REMOVE receives the bus start address of the window
> >> +and removes it.
> >> +
> >>   -------------------------------------------------------------------------------
> >>
> >>   [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 13145a2..bac02bf 100644
> >> --- a/arch/powerpc/include/asm/iommu.h
> >> +++ b/arch/powerpc/include/asm/iommu.h
> >> @@ -138,7 +138,7 @@ extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
> >>   extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
> >>   					    int nid);
> >>
> >> -#define IOMMU_TABLE_GROUP_MAX_TABLES	1
> >> +#define IOMMU_TABLE_GROUP_MAX_TABLES	2
> >>
> >>   struct iommu_table_group;
> >>
> >> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> >> index d94116b..0129a4f 100644
> >> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> >> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> >> @@ -600,11 +600,137 @@ static long tce_iommu_build(struct tce_container *container,
> >>   	return ret;
> >>   }
> >>
> >> +static int spapr_tce_find_free_table(struct tce_container *container)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
> >> +		struct iommu_table *tbl = &container->tables[i];
> >> +
> >> +		if (!tbl->it_size)
> >> +			return i;
> >> +	}
> >> +
> >> +	return -ENOSPC;
> >> +}
> >> +
> >> +static long tce_iommu_create_window(struct tce_container *container,
> >> +		__u32 page_shift, __u64 window_size, __u32 levels,
> >> +		__u64 *start_addr)
> >> +{
> >> +	struct tce_iommu_group *tcegrp;
> >> +	struct iommu_table_group *table_group;
> >> +	struct iommu_table *tbl;
> >> +	int num;
> >> +	long ret;
> >> +
> >> +	num = spapr_tce_find_free_table(container);
> >> +	if (num < 0)
> >> +		return num;
> >> +
> >> +	tbl = &container->tables[num];
> >> +
> >> +	/* Get the first group for ops::create_table */
> >> +	tcegrp = list_first_entry(&container->group_list,
> >> +			struct tce_iommu_group, next);
> >> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
> >> +	if (!table_group)
> >> +		return -EFAULT;
> >> +
> >> +	if (!(table_group->pgsizes & (1ULL << page_shift)))
> >> +		return -EINVAL;
> >> +
> >> +	if (!table_group->ops->set_window || !table_group->ops->unset_window ||
> >> +			!table_group->ops->create_table)
> >> +		return -EPERM;
> >> +
> >> +	/* Create TCE table */
> >> +	ret = table_group->ops->create_table(table_group, num,
> >> +			page_shift, window_size, levels, tbl);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	BUG_ON(!tbl->it_ops->free);
> >> +
> >> +	/*
> >> +	 * Program the table to every group.
> >> +	 * Groups have been tested for compatibility at the attach time.
> >> +	 */
> >> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> >> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> >> +
> >> +		ret = table_group->ops->set_window(table_group, num, tbl);
> >> +		if (ret)
> >> +			goto unset_exit;
> >> +	}
> >> +
> >> +	/* Return start address assigned by platform in create_table() */
> >> +	*start_addr = tbl->it_offset << tbl->it_page_shift;
> >> +
> >> +	return 0;
> >> +
> >> +unset_exit:
> >> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> >> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> >> +		table_group->ops->unset_window(table_group, num);
> >> +	}
> >> +	tbl->it_ops->free(tbl);
> >> +	memset(tbl, 0, sizeof(*tbl));
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static long tce_iommu_remove_window(struct tce_container *container,
> >> +		__u64 start_addr)
> >> +{
> >> +	struct iommu_table_group *table_group = NULL;
> >> +	struct iommu_table *tbl;
> >> +	struct tce_iommu_group *tcegrp;
> >> +	int num;
> >> +
> >> +	tbl = spapr_tce_find_table(container, start_addr);
> >> +	if (!tbl)
> >> +		return -EINVAL;
> >> +
> >> +	/* Detach groups from IOMMUs */
> >> +	num = tbl - container->tables;
> >> +	list_for_each_entry(tcegrp, &container->group_list, next) {
> >> +		table_group = iommu_group_get_iommudata(tcegrp->grp);
> >> +
> >> +		/*
> >> +		 * When a group is attached, a window might be set if DDW
> >> +		 * is supported by the platform. If it is not, VFIO will
> >> +		 * use the existing window created by the platform code
> >> +		 * so spapr_tce_find_table() will find a table but
> >> +		 * since it is owned by the platform code, ops or unset_window()
> >> +		 * will not be defined. If in this situation a broken
> >> +		 * guest calls VFIO_IOMMU_SPAPR_TCE_REMOVE, we crash here
> >> +		 * without the check.
> >> +		 */
> >
> > Doesn't this indicate a more serious issue if a user can remove windows
> > that they didn't create?  It seems like that would open us to all sorts
>  > of inconsistent state, if not exploits.
> 
> 
> The existing upstream QEMU expects the default window to exits. So there is 
> at least one situation when there is a window which the user did not create.
> 
> 1. A window can be owned by the "powernv" platform or VFIO. If it is 
> "powernv" (old power7 IO chips) - removal of a window is not enabled, 
> otherwise (new power8 chip) it is.
> 
> 2. Old QEMU expects the default window to exist. If it is "powernv" owned 
> window, then VFIO just reuses it, otherwise it creates one.
> 
> What is inconsistent about the state? Or I just document it in 
> Documentation/vfio.txt and that's it?

Perhaps the comment simply needs to be made more clear.  I think what
you're saying is that dma32_window_start and size can be exposed through
vfio_iommu_spapr_tce_info and some platforms allow the user to remove
this TCE window.  On platforms that do not support that, the user is not
permitted to remove the window and we check that platform capability
here.

> >> +		if (!table_group->ops || !table_group->ops->unset_window)
> >> +			return -EPERM;
> >> +
> >> +		if (container->tables[num].it_size)
> >> +			table_group->ops->unset_window(table_group, num);
> >> +	}
> >> +
> >> +	/* Free table */
> >> +	tcegrp = list_first_entry(&container->group_list,
> >> +			struct tce_iommu_group, next);
> >> +	table_group = iommu_group_get_iommudata(tcegrp->grp);
> >> +
> >> +	tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
> >> +	tbl->it_ops->free(tbl);
> >> +	memset(tbl, 0, sizeof(*tbl));
> >> +
> >> +	return 0;
> >> +}
> >> +
> >>   static long tce_iommu_ioctl(void *iommu_data,
> >>   				 unsigned int cmd, unsigned long arg)
> >>   {
> >>   	struct tce_container *container = iommu_data;
> >> -	unsigned long minsz;
> >> +	unsigned long minsz, ddwsz;
> >>   	long ret;
> >>
> >>   	switch (cmd) {
> >> @@ -645,9 +771,24 @@ static long tce_iommu_ioctl(void *iommu_data,
> >>   		if (info.argsz < minsz)
> >>   			return -EINVAL;
> >>
> >> +		info.flags = 0;
> >
> > This should not have been removed in the previous patch
> 
> Ouch. Multiple rebase result :)
> 
> 
> >>   		info.dma32_window_start = table_group->tce32_start;
> >>   		info.dma32_window_size = table_group->tce32_size;
> >>
> >> +		if (table_group->max_dynamic_windows_supported) {
> >> +			info.flags = VFIO_IOMMU_INFO_DDW;
> >
> > Shouldn't this be |= ?
> >
> >> +			info.pgsizes = table_group->pgsizes;
> >> +			info.max_dynamic_windows_supported =
> >> +				table_group->max_dynamic_windows_supported;
> >> +			info.levels = table_group->max_levels;
> >> +		}
> >> +
> >> +		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info,
> >> +				levels);
> >> +
> >> +		if (info.argsz == ddwsz)
> >> +			minsz = ddwsz;
> >> +
> >
> > How about >= ?  Requiring == means that a new userspace that might know
> > about a new field added to a later kernel will break on this kernel.
> >
> > Also, if DDW is not supported, you're just about to write uninitialized
> > kernel data to userspace :-\
> >
> >>   		if (copy_to_user((void __user *)arg, &info, minsz))
> 
> 
> then copy_to_user(..., info.argsz) is the answer, no? I do not really want 
> to touch the area of the struct I do not support in this call, unless there 
> is some code guideline for ioctl implementation.

What you write back to the user should be a) no bigger than they've told
you they've allocated and b) only initialized data, zero or actual
values.  Copying uninitialized data to userspace can have security
consequences.  I don't particularly care if you write short when ddw is
not supported or write zeros, but the docs need to make it clear that
those fields are only valid when the ddw flag is set.  If this structure
gets extended again by another flag in the future, we'll probably just
want to zero initialize fields rather than attempt sparse writes to the
structure, so maybe it makes sense to do that now.

> >>   			return -EFAULT;
> >>
> >> @@ -830,6 +971,69 @@ static long tce_iommu_ioctl(void *iommu_data,
> >>   		return ret;
> >>   	}
> >>
> >> +	case VFIO_IOMMU_SPAPR_TCE_CREATE: {
> >> +		struct vfio_iommu_spapr_tce_create create;
> >> +
> >> +		if (!tce_preregistered(container))
> >> +			return -EPERM;
> >> +
> >> +		if (!tce_groups_attached(container))
> >> +			return -ENXIO;
> >> +
> >> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_create,
> >> +				start_addr);
> >> +
> >> +		if (copy_from_user(&create, (void __user *)arg, minsz))
> >> +			return -EFAULT;
> >> +
> >> +		if (create.argsz < minsz)
> >> +			return -EINVAL;
> >> +
> >> +		if (create.flags)
> >> +			return -EINVAL;
> >> +
> >> +		mutex_lock(&container->lock);
> >> +
> >> +		ret = tce_iommu_create_window(container, create.page_shift,
> >> +				create.window_size, create.levels,
> >> +				&create.start_addr);
> >> +
> >> +		if (!ret && copy_to_user((void __user *)arg, &create, minsz))
> >> +			ret = -EFAULT;
> >> +
> >> +		mutex_unlock(&container->lock);
> >
> > Even easier would be to move the unlock up, we probably don't need to
> > protect the copy_to_user().
>  >
> >> +
> >> +		return ret;
> >> +	}
> >> +	case VFIO_IOMMU_SPAPR_TCE_REMOVE: {
> >> +		struct vfio_iommu_spapr_tce_remove remove;
> >> +
> >> +		if (!tce_preregistered(container))
> >> +			return -EPERM;
> >> +
> >> +		if (!tce_groups_attached(container))
> >> +			return -ENXIO;
> >> +
> >> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_remove,
> >> +				start_addr);
> >> +
> >> +		if (copy_from_user(&remove, (void __user *)arg, minsz))
> >> +			return -EFAULT;
> >> +
> >> +		if (remove.argsz < minsz)
> >> +			return -EINVAL;
> >> +
> >> +		if (remove.flags)
> >> +			return -EINVAL;
> >> +
> >> +		mutex_lock(&container->lock);
> >> +
> >> +		ret = tce_iommu_remove_window(container, remove.start_addr);
> >> +
> >> +		mutex_unlock(&container->lock);
> >> +
> >> +		return ret;
> >> +	}
> >>   	}
> >>
> >>   	return -ENOTTY;
> >> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> >> index fbc5286..7fa02e1 100644
> >> --- a/include/uapi/linux/vfio.h
> >> +++ b/include/uapi/linux/vfio.h
> >> @@ -457,9 +457,13 @@ struct vfio_iommu_type1_dma_unmap {
> >>    */
> >>   struct vfio_iommu_spapr_tce_info {
> >>   	__u32 argsz;
> >> -	__u32 flags;			/* reserved for future use */
> >> +	__u32 flags;
> >> +#define VFIO_IOMMU_INFO_DDW	(1 << 0)	/* DDW supported */
> >
> > s/VFIO_IOMMU_INFO_DDW/VFIO_IOMMU_SPAPR_INFO_DDW/
> 
> VFIO_IOMMU_INFO_PGSIZES is not VFIO_IOMMU_TYPE1_INFO_PGSIZES ;-) but I'll fix.

Too late to complain about that one now.

> >
> >>   	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
> >>   	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
> >> +	__u64 pgsizes;			/* Bitmap of supported page sizes */
> >> +	__u32 max_dynamic_windows_supported;
> >> +	__u32 levels;
> >
> > Please indicate that the last 3 fields are only supported with DDW.
> 
> 
> Like this?
> 
> ===
> - * A flag will need to be added if other page sizes are supported,
> - * so as defined here, it is always 4k.
> + * Flags supported:
> + * - VFIO_IOMMU_INFO_DDW: informs the userspace that dynamic DMA windows
> + *   (DDW) support is present. @pgsizes, @max_dynamic_windows_supported,
> + *   @levels are only supported when DDW is present.
>    */
>   struct vfio_iommu_spapr_tce_info {
>          __u32 argsz;

Yeah, I might try to say that the value of those fields is only valid
when the ddw flag is set.  Additionally, the comment next to the field
could say "Only with DDW".

You might also want to consider if you want all 3 of these fields
toggled by a single flag.  Does it make sense to advertise pgsize,
max-ddw, and levels each as a separate flag?  Alternatively, you could
embed at struct to make the association to the flag more clear:

struct blah_blah_ddw_info {
	__u64 pgsizes;
	__u32 max_ddws;
	__u32 levels;
};

struct vfio_iommu_spapr_tce_info {
	...
	struct blah_blah_ddw_info ddw; /* only valid with DDW flag */


> ===
> 
> 
> >
> >>   };
> >>
> >>   #define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
> >> @@ -520,6 +524,41 @@ struct vfio_iommu_spapr_register_memory {
> >>    */
> >>   #define VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY	_IO(VFIO_TYPE, VFIO_BASE + 18)
> >>
> >> +/**
> >> + * VFIO_IOMMU_SPAPR_TCE_CREATE - _IOWR(VFIO_TYPE, VFIO_BASE + 19, struct vfio_iommu_spapr_tce_create)
> >> + *
> >> + * Creates an additional TCE table and programs it (sets a new DMA window)
> >> + * to every IOMMU group in the container. It receives page shift, window
> >> + * size and number of levels in the TCE table being created.
> >> + *
> >> + * It allocates and returns an offset on a PCI bus of the new DMA window.
> >> + */
> >> +struct vfio_iommu_spapr_tce_create {
> >> +	__u32 argsz;
> >> +	__u32 flags;
> >> +	/* in */
> >> +	__u32 page_shift;
> >> +	__u64 window_size;
> >> +	__u32 levels;
> >> +	/* out */
> >> +	__u64 start_addr;
> >> +};
> >> +#define VFIO_IOMMU_SPAPR_TCE_CREATE	_IO(VFIO_TYPE, VFIO_BASE + 19)
> >> +
> >> +/**
> >> + * VFIO_IOMMU_SPAPR_TCE_REMOVE - _IOW(VFIO_TYPE, VFIO_BASE + 20, struct vfio_iommu_spapr_tce_remove)
> >> + *
> >> + * Unprograms a TCE table from all groups in the container and destroys it.
> >> + * It receives a PCI bus offset as a window id.
> >> + */
> >> +struct vfio_iommu_spapr_tce_remove {
> >> +	__u32 argsz;
> >> +	__u32 flags;
> >> +	/* in */
> >> +	__u64 start_addr;
> >> +};
> >> +#define VFIO_IOMMU_SPAPR_TCE_REMOVE	_IO(VFIO_TYPE, VFIO_BASE + 20)
> >> +
> >>   /* ***************************************************************** */
> >>
> >>   #endif /* _UAPIVFIO_H */
> >
> >
> >
> 
> 

Re: [PATCH kernel v6 26/29] vfio: powerpc/spapr: Define v2 IOMMU

[Alexey Kardashevskiy]

On 03/17/2015 06:45 AM, Alex Williamson wrote:
> On Fri, 2015-03-13 at 19:07 +1100, Alexey Kardashevskiy wrote:
>> The existing IOMMU requires VFIO_IOMMU_ENABLE call to enable actual use
>> of the container (i.e. call DMA map/unmap) and this is where we check
>> the rlimit for locked pages. It assumes that only as much memory
>> as a default DMA window can be mapped. Every DMA map/unmap request will
>> do pinning/unpinning of physical pages.
>>
>> New IOMMU will split physical pages pinning and TCE table update.
>> It will require guest pages to be registered first and 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.
>> However when a huge DMA window is added, no additional pinning will be
>> required, otherwise it would be guest RAM + 2GB.
>>
>> This advertises v2 SPAPR TCE IOMMU and restricts what the userspace
>> can do with v1 or v2 IOMMUs.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> Changes:
>> v6:
>> * enforced limitations imposed by the SPAPR TCE IOMMU version
>> ---
>>   drivers/vfio/vfio_iommu_spapr_tce.c | 18 +++++++++++++++++-
>>   include/uapi/linux/vfio.h           |  2 ++
>>   2 files changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
>> index 9d240b4..e191438 100644
>> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
>> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
>> @@ -95,6 +95,7 @@ struct tce_container {
>>   	bool enabled;
>>   	unsigned long locked_pages;
>>   	struct list_head mem_list;
>> +	bool v2;
>>   };
>>
>>   struct tce_memory {
>> @@ -398,7 +399,7 @@ 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);
>>   	}
>> @@ -410,6 +411,8 @@ static void *tce_iommu_open(unsigned long arg)
>>   	mutex_init(&container->lock);
>>   	INIT_LIST_HEAD_RCU(&container->mem_list);
>>
>> +	container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
>> +
>>   	return container;
>>   }
>>
>> @@ -580,6 +583,7 @@ 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:
>> @@ -719,6 +723,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>>   	case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
>>   		struct vfio_iommu_spapr_register_memory param;
>>
>> +		if (!container->v2)
>> +			return -EPERM;
>> +
>>   		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
>>   				size);
>>
>> @@ -741,6 +748,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>>   	case VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY: {
>>   		struct vfio_iommu_spapr_register_memory param;
>>
>> +		if (!container->v2)
>> +			return -EPERM;
>> +
>>   		minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
>>   				size);
>>
>> @@ -761,6 +771,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>>   		return 0;
>>   	}
>>   	case VFIO_IOMMU_ENABLE:
>> +		if (container->v2)
>> +			return -EPERM;
>> +
>>   		mutex_lock(&container->lock);
>>   		ret = tce_iommu_enable(container);
>>   		mutex_unlock(&container->lock);
>> @@ -768,6 +781,9 @@ static long tce_iommu_ioctl(void *iommu_data,
>>
>>
>>   	case VFIO_IOMMU_DISABLE:
>> +		if (container->v2)
>> +			return -EPERM;
>> +
>>   		mutex_lock(&container->lock);
>>   		tce_iommu_disable(container);
>>   		mutex_unlock(&container->lock);
>
>
> I wouldn't have guessed; nothing in the documentation suggests these
> ioctls are deprecated in v2 (ie. please document).  If the ioctl doesn't
> exist for the IOMMU type, why not simply break and let it fall out at
> -ENOTTY?  Same for the above, v1 would have previously returned -ENOTTY
> for those ioctls, why change to -EPERM?


Good points. I'll fix them and merge this patch to "vfio: powerpc/spapr: 
Register memory" as this is where it actually belongs to. Agree?


Thanks for the review!


-- 
Alexey