[PATCH 0/2] vfio on power

[PATCH 0/2] vfio on power

[Alexey Kardashevskiy]

The series introduces a VFIO support on POWER.
The QEMU support is required, the real mode acceleration patches are coming later.

Alexey Kardashevskiy (2):
  vfio powerpc: enabled on powernv platform
  vfio powerpc: implemented IOMMU driver for VFIO

 arch/powerpc/include/asm/iommu.h            |   15 ++
 arch/powerpc/kernel/iommu.c                 |  343 +++++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/pci-ioda.c   |    1 +
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |    5 +-
 arch/powerpc/platforms/powernv/pci.c        |    3 +
 drivers/iommu/Kconfig                       |    8 +
 drivers/vfio/Kconfig                        |    6 +
 drivers/vfio/Makefile                       |    1 +
 drivers/vfio/vfio_iommu_spapr_tce.c         |  269 +++++++++++++++++++++
 include/uapi/linux/vfio.h                   |   31 +++
 10 files changed, 681 insertions(+), 1 deletion(-)
 create mode 100644 drivers/vfio/vfio_iommu_spapr_tce.c

-- 
1.7.10.4

[PATCH 1/2] vfio powerpc: enabled on powernv platform

[Alexey Kardashevskiy]

This patch initializes IOMMU groups based on the IOMMU
configuration discovered during the PCI scan on POWERNV
(POWER non virtualized) platform. The IOMMU groups are
to be used later by VFIO driver (PCI pass through).

It also implements an API for mapping/unmapping pages for
guest PCI drivers and providing DMA window properties.
This API is going to be used later by QEMU-VFIO to handle
h_put_tce hypercalls from the KVM guest.

The iommu_put_tce_user_mode() does only a single page mapping
as an API for adding many mappings at once is going to be
added later.

Although this driver has been tested only on the POWERNV
platform, it should work on any platform which supports
TCE tables. As h_put_tce hypercall is received by the host
kernel and processed by the QEMU (what involves calling
the host kernel again), performance is not the best -
circa 220MB/s on 10Gb ethernet network.

To enable VFIO on POWER, enable SPAPR_TCE_IOMMU config
option and configure VFIO as required.

Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/iommu.h            |   15 ++
 arch/powerpc/kernel/iommu.c                 |  343 +++++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/pci-ioda.c   |    1 +
 arch/powerpc/platforms/powernv/pci-p5ioc2.c |    5 +-
 arch/powerpc/platforms/powernv/pci.c        |    3 +
 drivers/iommu/Kconfig                       |    8 +
 6 files changed, 374 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index cbfe678..900294b 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -76,6 +76,9 @@ struct iommu_table {
 	struct iommu_pool large_pool;
 	struct iommu_pool pools[IOMMU_NR_POOLS];
 	unsigned long *it_map;       /* A simple allocation bitmap for now */
+#ifdef CONFIG_IOMMU_API
+	struct iommu_group *it_group;
+#endif
 };
 
 struct scatterlist;
@@ -98,6 +101,8 @@ 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);
+extern void iommu_register_group(struct iommu_table * tbl,
+				 int domain_number, unsigned long pe_num);
 
 extern int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 			struct scatterlist *sglist, int nelems,
@@ -147,5 +152,15 @@ static inline void iommu_restore(void)
 }
 #endif
 
+/* The API to support IOMMU operations for VFIO */
+extern long iommu_clear_tce_user_mode(struct iommu_table *tbl,
+		unsigned long ioba, unsigned long tce_value,
+		unsigned long npages);
+extern long iommu_put_tce_user_mode(struct iommu_table *tbl,
+		unsigned long ioba, unsigned long tce);
+
+extern void iommu_flush_tce(struct iommu_table *tbl);
+extern long iommu_lock_table(struct iommu_table *tbl, bool lock);
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_IOMMU_H */
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 7c309fe..b4fdabc 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -37,6 +37,7 @@
 #include <linux/fault-inject.h>
 #include <linux/pci.h>
 #include <linux/kvm_host.h>
+#include <linux/iommu.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/iommu.h>
@@ -45,6 +46,7 @@
 #include <asm/kdump.h>
 #include <asm/fadump.h>
 #include <asm/vio.h>
+#include <asm/tce.h>
 
 #define DBG(...)
 
@@ -707,11 +709,39 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 	return tbl;
 }
 
+static void group_release(void *iommu_data)
+{
+	struct iommu_table *tbl = iommu_data;
+	tbl->it_group = NULL;
+}
+
+void iommu_register_group(struct iommu_table * tbl,
+		int domain_number, unsigned long pe_num)
+{
+	struct iommu_group *grp;
+
+	grp = iommu_group_alloc();
+	if (IS_ERR(grp)) {
+		pr_info("powerpc iommu api: cannot create new group, err=%ld\n",
+				PTR_ERR(grp));
+		return;
+	}
+	tbl->it_group = grp;
+	iommu_group_set_iommudata(grp, tbl, group_release);
+	iommu_group_set_name(grp, kasprintf(GFP_KERNEL, "domain%d-pe%lx",
+			domain_number, pe_num));
+}
+
 void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 {
 	unsigned long bitmap_sz;
 	unsigned int order;
 
+	if (tbl && tbl->it_group) {
+		iommu_group_put(tbl->it_group);
+		BUG_ON(tbl->it_group);
+	}
+
 	if (!tbl || !tbl->it_map) {
 		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
 				node_name);
@@ -876,4 +906,317 @@ void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 {
 }
 
+static enum dma_data_direction tce_direction(unsigned long tce)
+{
+	if ((tce & TCE_PCI_READ) && (tce & TCE_PCI_WRITE))
+		return DMA_BIDIRECTIONAL;
+	else if (tce & TCE_PCI_READ)
+		return DMA_TO_DEVICE;
+	else if (tce & TCE_PCI_WRITE)
+		return DMA_FROM_DEVICE;
+	else
+		return DMA_NONE;
+}
+
+void iommu_flush_tce(struct iommu_table *tbl)
+{
+	/* Flush/invalidate TLB caches if necessary */
+	if (ppc_md.tce_flush)
+		ppc_md.tce_flush(tbl);
+
+	/* Make sure updates are seen by hardware */
+	mb();
+}
+EXPORT_SYMBOL_GPL(iommu_flush_tce);
+
+static long tce_clear_param_check(struct iommu_table *tbl,
+		unsigned long ioba, unsigned long tce_value,
+		unsigned long npages)
+{
+	unsigned long size = npages << IOMMU_PAGE_SHIFT;
+
+	/* ppc_md.tce_free() does not support any value but 0 */
+	if (tce_value)
+		return -EINVAL;
+
+	if (ioba & ~IOMMU_PAGE_MASK)
+		return -EINVAL;
+
+	if ((ioba + size) > ((tbl->it_offset + tbl->it_size)
+			<< IOMMU_PAGE_SHIFT))
+		return -EINVAL;
+
+	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
+		return -EINVAL;
+
+	return 0;
+}
+
+static long 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 | TCE_PCI_WRITE | TCE_PCI_READ))
+		return -EINVAL;
+
+	if (ioba & ~IOMMU_PAGE_MASK)
+		return -EINVAL;
+
+	if ((ioba + IOMMU_PAGE_SIZE) > ((tbl->it_offset + tbl->it_size)
+			<< IOMMU_PAGE_SHIFT))
+		return -EINVAL;
+
+	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
+		return -EINVAL;
+
+	return 0;
+}
+
+static long clear_tce(struct iommu_table *tbl,
+		unsigned long entry, unsigned long pages)
+{
+	unsigned long oldtce;
+	struct page *page;
+	struct iommu_pool *pool;
+
+	for ( ; pages; --pages, ++entry) {
+		pool = get_pool(tbl, entry);
+		spin_lock(&(pool->lock));
+
+		oldtce = ppc_md.tce_get(tbl, entry);
+		if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)) {
+			ppc_md.tce_free(tbl, entry, 1);
+
+			page = pfn_to_page(oldtce >> PAGE_SHIFT);
+			WARN_ON(!page);
+			if (page) {
+				if (oldtce & TCE_PCI_WRITE)
+					SetPageDirty(page);
+				put_page(page);
+			}
+		}
+		spin_unlock(&(pool->lock));
+	}
+
+	return 0;
+}
+
+long iommu_clear_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
+		unsigned long tce_value, unsigned long npages)
+{
+	long ret;
+	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
+
+	ret = tce_clear_param_check(tbl, ioba, tce_value, npages);
+	if (!ret)
+		ret = clear_tce(tbl, entry, npages);
+
+	if (ret < 0)
+		pr_err("iommu_tce: %s failed ioba=%lx, tce_value=%lx ret=%ld\n",
+				__func__, ioba, tce_value, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_clear_tce_user_mode);
+
+/* hwaddr is a virtual address here, tce_build converts it to physical */
+static long do_tce_build(struct iommu_table *tbl, unsigned long entry,
+		unsigned long hwaddr, enum dma_data_direction direction)
+{
+	long ret = -EBUSY;
+	unsigned long oldtce;
+	struct iommu_pool *pool = get_pool(tbl, entry);
+
+	spin_lock(&(pool->lock));
+
+	oldtce = ppc_md.tce_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);
+
+	spin_unlock(&(pool->lock));
+
+	if (unlikely(ret))
+		pr_err("iommu_tce: %s failed on hwaddr=%lx ioba=%lx kva=%lx ret=%ld\n",
+				__func__, hwaddr, entry << IOMMU_PAGE_SHIFT,
+				hwaddr, ret);
+
+	return ret;
+}
+
+static int 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 & ~PAGE_MASK;
+	enum dma_data_direction direction = 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 << IOMMU_PAGE_SHIFT, ret);
+		return -EFAULT;
+	}
+	hwaddr = (unsigned long) page_address(page) + offset;
+
+	ret = do_tce_build(tbl, entry, hwaddr, direction);
+	if (ret)
+		put_page(page);
+
+	return ret;
+}
+
+long iommu_put_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
+		unsigned long tce)
+{
+	long ret;
+	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
+
+	ret = tce_put_param_check(tbl, ioba, tce);
+	if (!ret)
+		ret = put_tce_user_mode(tbl, entry, tce);
+
+	if (ret < 0)
+		pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
+				__func__, ioba, tce, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
+
+/*
+ * Helpers to do locked pages accounting.
+ * Called from ioctl so down_write_trylock is not necessary.
+ */
+static void lock_acct(long npage)
+{
+	if (!current->mm)
+		return; /* process exited */
+
+	down_write(&current->mm->mmap_sem);
+	current->mm->locked_vm += npage;
+	up_write(&current->mm->mmap_sem);
+}
+
+/*
+ * iommu_lock_table - Start/stop using the table by VFIO
+ * @tbl: Pointer to the IOMMU table
+ * @lock: true when VFIO starts using the table
+ */
+long iommu_lock_table(struct iommu_table *tbl, bool lock)
+{
+	unsigned long sz = (tbl->it_size + 7) >> 3;
+	unsigned long locked, lock_limit;
+
+	if (lock) {
+		/*
+		 * Account for locked pages
+		 * The worst case is when every IOMMU page
+		 * is mapped to separate system page
+		 */
+		locked = current->mm->locked_vm + tbl->it_size;
+		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));
+			return -ENOMEM;
+		}
+
+		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;
+		}
+
+		lock_acct(tbl->it_size);
+		memset(tbl->it_map, 0xff, sz);
+	}
+
+	/* Clear TCE table */
+	clear_tce(tbl, tbl->it_offset, tbl->it_size);
+
+	if (!lock) {
+		lock_acct(-tbl->it_size);
+		memset(tbl->it_map, 0, sz);
+
+		/* Restore bit#0 set by iommu_init_table() */
+		if (tbl->it_offset == 0)
+			set_bit(0, tbl->it_map);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iommu_lock_table);
+
+int iommu_add_device(struct device *dev)
+{
+	struct iommu_table *tbl;
+	int ret = 0;
+
+	if (WARN_ON(dev->iommu_group)) {
+		pr_warn("iommu_tce: device %s is already in iommu group %d, skipping\n",
+				dev_name(dev),
+				iommu_group_id(dev->iommu_group));
+		return -EBUSY;
+	}
+
+	tbl = get_iommu_table_base(dev);
+	if (!tbl) {
+		pr_debug("iommu_tce: skipping device %s with no tbl\n",
+				dev_name(dev));
+		return 0;
+	}
+
+	pr_debug("iommu_tce: adding %s to iommu group %d\n",
+			dev_name(dev), iommu_group_id(tbl->it_group));
+
+	ret = iommu_group_add_device(tbl->it_group, dev);
+	if (ret < 0)
+		pr_err("iommu_tce: %s has not been added, ret=%d\n",
+				dev_name(dev), ret);
+
+	return ret;
+}
+
+void iommu_del_device(struct device *dev)
+{
+	iommu_group_remove_device(dev);
+}
+
+static int iommu_bus_notifier(struct notifier_block *nb,
+			      unsigned long action, void *data)
+{
+	struct device *dev = data;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		return iommu_add_device(dev);
+	case BUS_NOTIFY_DEL_DEVICE:
+		iommu_del_device(dev);
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+static struct notifier_block tce_iommu_bus_nb = {
+	.notifier_call = iommu_bus_notifier,
+};
+
+static int __init tce_iommu_init(void)
+{
+	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
+
+	bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
+	return 0;
+}
+
+arch_initcall(tce_iommu_init);
+
 #endif /* CONFIG_IOMMU_API */
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 8e90e89..04dbc49 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -522,6 +522,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 			| TCE_PCI_SWINV_PAIR;
 	}
 	iommu_init_table(tbl, phb->hose->node);
+	iommu_register_group(tbl, pci_domain_nr(pe->pbus), pe->pe_number);
 
 	if (pe->pdev)
 		set_iommu_table_base(&pe->pdev->dev, tbl);
diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
index abe6780..7ce75b0 100644
--- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
+++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
@@ -87,8 +87,11 @@ 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)
+	if (phb->p5ioc2.iommu_table.it_map == NULL) {
 		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);
+	}
 
 	set_iommu_table_base(&pdev->dev, &phb->p5ioc2.iommu_table);
 }
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index f60a188..d112701 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -20,6 +20,7 @@
 #include <linux/irq.h>
 #include <linux/io.h>
 #include <linux/msi.h>
+#include <linux/iommu.h>
 
 #include <asm/sections.h>
 #include <asm/io.h>
@@ -503,6 +504,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
 	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
 				  be32_to_cpup(sizep), 0);
 	iommu_init_table(tbl, hose->node);
+	iommu_register_group(tbl, 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",
@@ -631,3 +633,4 @@ void __init pnv_pci_init(void)
 	ppc_md.teardown_msi_irqs = pnv_teardown_msi_irqs;
 #endif
 }
+
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index e39f9db..ce6b186 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -187,4 +187,12 @@ config EXYNOS_IOMMU_DEBUG
 
 	  Say N unless you need kernel log message for IOMMU debugging
 
+config SPAPR_TCE_IOMMU
+	bool "sPAPR TCE IOMMU Support"
+	depends on PPC_POWERNV
+	select IOMMU_API
+	help
+	  Enables bits of IOMMU API required by VFIO. The iommu_ops is
+	  still not implemented.
+
 endif # IOMMU_SUPPORT
-- 
1.7.10.4

[PATCH 2/2] vfio powerpc: implemented IOMMU driver for VFIO

[Alexey Kardashevskiy]

VFIO implements platform independent stuff such as
a PCI driver, BAR access (via read/write on a file descriptor
or direct mapping when possible) and IRQ signaling.

The platform dependent part includes IOMMU initialization
and handling. This patch implements an IOMMU driver for VFIO
which does mapping/unmapping pages for the guest IO and
provides information about DMA window (required by a POWERPC
guest).

The counterpart in QEMU is required to support this functionality.

Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 drivers/vfio/Kconfig                |    6 +
 drivers/vfio/Makefile               |    1 +
 drivers/vfio/vfio_iommu_spapr_tce.c |  269 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h           |   31 ++++
 4 files changed, 307 insertions(+)
 create mode 100644 drivers/vfio/vfio_iommu_spapr_tce.c

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index 7cd5dec..b464687 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -3,10 +3,16 @@ config VFIO_IOMMU_TYPE1
 	depends on VFIO
 	default n
 
+config VFIO_IOMMU_SPAPR_TCE
+	tristate
+	depends on VFIO && SPAPR_TCE_IOMMU
+	default n
+
 menuconfig VFIO
 	tristate "VFIO Non-Privileged userspace driver framework"
 	depends on IOMMU_API
 	select VFIO_IOMMU_TYPE1 if X86
+	select VFIO_IOMMU_SPAPR_TCE if PPC_POWERNV
 	help
 	  VFIO provides a framework for secure userspace device drivers.
 	  See Documentation/vfio.txt for more details.
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 2398d4a..72bfabc 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_VFIO) += vfio.o
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
+obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_PCI) += pci/
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
new file mode 100644
index 0000000..9b3fa88
--- /dev/null
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -0,0 +1,269 @@
+/*
+ * VFIO: IOMMU DMA mapping support for TCE on POWER
+ *
+ * Copyright (C) 2012 IBM Corp.  All rights reserved.
+ *     Author: Alexey Kardashevskiy <aik@ozlabs.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Derived from original vfio_iommu_type1.c:
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/err.h>
+#include <linux/vfio.h>
+#include <asm/iommu.h>
+#include <asm/tce.h>
+
+#define DRIVER_VERSION  "0.1"
+#define DRIVER_AUTHOR   "aik@ozlabs.ru"
+#define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"
+
+static void tce_iommu_detach_group(void *iommu_data,
+		struct iommu_group *iommu_group);
+
+/*
+ * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
+ *
+ * This code handles mapping and unmapping of user data buffers
+ * into DMA'ble space using the IOMMU
+ */
+
+/*
+ * The container descriptor supports only a single group per container.
+ * Required by the API as the container is not supplied with the IOMMU group
+ * at the moment of initialization.
+ */
+struct tce_container {
+	struct mutex lock;
+	struct iommu_table *tbl;
+};
+
+static void *tce_iommu_open(unsigned long arg)
+{
+	struct tce_container *container;
+
+	if (arg != VFIO_SPAPR_TCE_IOMMU) {
+		pr_err("tce_vfio: Wrong IOMMU type\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	container = kzalloc(sizeof(*container), GFP_KERNEL);
+	if (!container)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&container->lock);
+
+	return container;
+}
+
+static void tce_iommu_release(void *iommu_data)
+{
+	struct tce_container *container = iommu_data;
+
+	WARN_ON(container->tbl && !container->tbl->it_group);
+	if (container->tbl && container->tbl->it_group)
+		tce_iommu_detach_group(iommu_data, container->tbl->it_group);
+
+	mutex_destroy(&container->lock);
+
+	kfree(container);
+}
+
+static long tce_iommu_ioctl(void *iommu_data,
+				 unsigned int cmd, unsigned long arg)
+{
+	struct tce_container *container = iommu_data;
+	unsigned long minsz;
+	long ret;
+
+	switch (cmd) {
+	case VFIO_CHECK_EXTENSION:
+		return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0;
+
+	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
+		struct vfio_iommu_spapr_tce_info info;
+		struct iommu_table *tbl = container->tbl;
+
+		if (WARN_ON(!tbl))
+			return -ENXIO;
+
+		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
+				dma32_window_size);
+
+		if (copy_from_user(&info, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (info.argsz < minsz)
+			return -EINVAL;
+
+		info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT;
+		info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT;
+		info.flags = 0;
+
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
+
+		return 0;
+	}
+	case VFIO_IOMMU_MAP_DMA: {
+		vfio_iommu_spapr_tce_dma_map param;
+		struct iommu_table *tbl = container->tbl;
+		unsigned long tce;
+
+		if (WARN_ON(!tbl))
+			return -ENXIO;
+
+		minsz = offsetofend(vfio_iommu_spapr_tce_dma_map, size);
+
+		if (copy_from_user(&param, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (param.argsz < minsz)
+			return -EINVAL;
+
+		if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
+				VFIO_DMA_MAP_FLAG_WRITE))
+			return -EINVAL;
+
+		if ((param.size & ~IOMMU_PAGE_MASK) ||
+				(param.vaddr & ~IOMMU_PAGE_MASK))
+			return -EINVAL;
+
+		/* TODO: support multiple TCEs */
+		if (param.size != IOMMU_PAGE_SIZE) {
+			pr_err("VFIO map on POWER supports only %lu page size\n",
+					IOMMU_PAGE_SIZE);
+			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;
+
+		ret = iommu_put_tce_user_mode(tbl, param.iova, tce);
+		iommu_flush_tce(tbl);
+
+		return ret;
+	}
+	case VFIO_IOMMU_UNMAP_DMA: {
+		vfio_iommu_spapr_tce_dma_unmap param;
+		struct iommu_table *tbl = container->tbl;
+
+		if (WARN_ON(!tbl))
+			return -ENXIO;
+
+		minsz = offsetofend(vfio_iommu_spapr_tce_dma_unmap, 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;
+
+		if (param.size & ~IOMMU_PAGE_MASK)
+			return -EINVAL;
+
+		/* iova is checked by the IOMMU API */
+		ret = iommu_clear_tce_user_mode(tbl, param.iova, 0,
+				param.size >> IOMMU_PAGE_SHIFT);
+		iommu_flush_tce(tbl);
+
+		return ret;
+	}
+	}
+
+	return -ENOTTY;
+}
+
+static int tce_iommu_attach_group(void *iommu_data,
+		struct iommu_group *iommu_group)
+{
+	int ret;
+	struct tce_container *container = iommu_data;
+	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_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) {
+		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(iommu_group));
+		mutex_unlock(&container->lock);
+		return -EBUSY;
+	}
+
+	container->tbl = tbl;
+	ret = iommu_lock_table(tbl, true);
+	mutex_unlock(&container->lock);
+
+	return ret;
+}
+
+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);
+
+	BUG_ON(!tbl);
+	mutex_lock(&container->lock);
+	if (tbl != container->tbl) {
+		pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
+				iommu_group_id(iommu_group),
+				iommu_group_id(tbl->it_group));
+	} else {
+
+		pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
+				iommu_group_id(iommu_group), iommu_group);
+
+		container->tbl = NULL;
+		iommu_lock_table(tbl, false);
+	}
+	mutex_unlock(&container->lock);
+}
+
+const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
+	.name		= "iommu-vfio-powerpc",
+	.owner		= THIS_MODULE,
+	.open		= tce_iommu_open,
+	.release	= tce_iommu_release,
+	.ioctl		= tce_iommu_ioctl,
+	.attach_group	= tce_iommu_attach_group,
+	.detach_group	= tce_iommu_detach_group,
+};
+
+static int __init tce_iommu_init(void)
+{
+	return vfio_register_iommu_driver(&tce_iommu_driver_ops);
+}
+
+static void __exit tce_iommu_cleanup(void)
+{
+	vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
+}
+
+module_init(tce_iommu_init);
+module_exit(tce_iommu_cleanup);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 4758d1b..ea9a9a7 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -22,6 +22,7 @@
 /* Extensions */
 
 #define VFIO_TYPE1_IOMMU		1
+#define VFIO_SPAPR_TCE_IOMMU		2
 
 /*
  * The IOCTL interface is designed for extensibility by embedding the
@@ -365,4 +366,34 @@ struct vfio_iommu_type1_dma_unmap {
 
 #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
 
+/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
+
+/*
+ * The SPAPR TCE info struct provides the information about the PCI bus
+ * address ranges available for DMA, these values are programmed into
+ * the hardware so the guest has to know that information.
+ *
+ * The DMA 32 bit window start is an absolute PCI bus address.
+ * The IOVA address passed via map/unmap ioctls are absolute PCI bus
+ * addresses too so the window works as a filter rather than an offset
+ * for IOVA addresses.
+ *
+ * A flag will need to be added if other page sizes are supported,
+ * so as defined here, it is always 4k.
+ */
+struct vfio_iommu_spapr_tce_info {
+	__u32 argsz;
+	__u32 flags;			/* reserved for future use */
+	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
+	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
+};
+
+#define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
+
+/* Reuse type1 map/unmap structs as they are the same at the moment */
+typedef struct vfio_iommu_type1_dma_map vfio_iommu_spapr_tce_dma_map;
+typedef struct vfio_iommu_type1_dma_unmap vfio_iommu_spapr_tce_dma_unmap;
+
+/* ***************************************************************** */
+
 #endif /* _UAPIVFIO_H */
-- 
1.7.10.4

Re: [PATCH 1/2] vfio powerpc: enabled on powernv platform

[Alex Williamson]

On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
> This patch initializes IOMMU groups based on the IOMMU
> configuration discovered during the PCI scan on POWERNV
> (POWER non virtualized) platform. The IOMMU groups are
> to be used later by VFIO driver (PCI pass through).
> 
> It also implements an API for mapping/unmapping pages for
> guest PCI drivers and providing DMA window properties.
> This API is going to be used later by QEMU-VFIO to handle
> h_put_tce hypercalls from the KVM guest.
> 
> The iommu_put_tce_user_mode() does only a single page mapping
> as an API for adding many mappings at once is going to be
> added later.
> 
> Although this driver has been tested only on the POWERNV
> platform, it should work on any platform which supports
> TCE tables. As h_put_tce hypercall is received by the host
> kernel and processed by the QEMU (what involves calling
> the host kernel again), performance is not the best -
> circa 220MB/s on 10Gb ethernet network.
> 
> To enable VFIO on POWER, enable SPAPR_TCE_IOMMU config
> option and configure VFIO as required.
> 
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Yay, it's not dead! ;)

I'd love some kind of changelog to know what to look for in here,
especially given 2mo since the last version.

> ---
>  arch/powerpc/include/asm/iommu.h            |   15 ++
>  arch/powerpc/kernel/iommu.c                 |  343 +++++++++++++++++++++++++++
>  arch/powerpc/platforms/powernv/pci-ioda.c   |    1 +
>  arch/powerpc/platforms/powernv/pci-p5ioc2.c |    5 +-
>  arch/powerpc/platforms/powernv/pci.c        |    3 +
>  drivers/iommu/Kconfig                       |    8 +
>  6 files changed, 374 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index cbfe678..900294b 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -76,6 +76,9 @@ struct iommu_table {
>  	struct iommu_pool large_pool;
>  	struct iommu_pool pools[IOMMU_NR_POOLS];
>  	unsigned long *it_map;       /* A simple allocation bitmap for now */
> +#ifdef CONFIG_IOMMU_API
> +	struct iommu_group *it_group;
> +#endif
>  };
>  
>  struct scatterlist;
> @@ -98,6 +101,8 @@ 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);
> +extern void iommu_register_group(struct iommu_table * tbl,
> +				 int domain_number, unsigned long pe_num);
>  
>  extern int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
>  			struct scatterlist *sglist, int nelems,
> @@ -147,5 +152,15 @@ static inline void iommu_restore(void)
>  }
>  #endif
>  
> +/* The API to support IOMMU operations for VFIO */
> +extern long iommu_clear_tce_user_mode(struct iommu_table *tbl,
> +		unsigned long ioba, unsigned long tce_value,
> +		unsigned long npages);
> +extern long iommu_put_tce_user_mode(struct iommu_table *tbl,
> +		unsigned long ioba, unsigned long tce);
> +
> +extern void iommu_flush_tce(struct iommu_table *tbl);
> +extern long iommu_lock_table(struct iommu_table *tbl, bool lock);
> +
>  #endif /* __KERNEL__ */
>  #endif /* _ASM_IOMMU_H */
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index 7c309fe..b4fdabc 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -37,6 +37,7 @@
>  #include <linux/fault-inject.h>
>  #include <linux/pci.h>
>  #include <linux/kvm_host.h>
> +#include <linux/iommu.h>
>  #include <asm/io.h>
>  #include <asm/prom.h>
>  #include <asm/iommu.h>
> @@ -45,6 +46,7 @@
>  #include <asm/kdump.h>
>  #include <asm/fadump.h>
>  #include <asm/vio.h>
> +#include <asm/tce.h>
>  
>  #define DBG(...)
>  
> @@ -707,11 +709,39 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
>  	return tbl;
>  }
>  
> +static void group_release(void *iommu_data)
> +{
> +	struct iommu_table *tbl = iommu_data;
> +	tbl->it_group = NULL;
> +}
> +
> +void iommu_register_group(struct iommu_table * tbl,
> +		int domain_number, unsigned long pe_num)
> +{
> +	struct iommu_group *grp;
> +
> +	grp = iommu_group_alloc();
> +	if (IS_ERR(grp)) {
> +		pr_info("powerpc iommu api: cannot create new group, err=%ld\n",
> +				PTR_ERR(grp));
> +		return;
> +	}
> +	tbl->it_group = grp;
> +	iommu_group_set_iommudata(grp, tbl, group_release);
> +	iommu_group_set_name(grp, kasprintf(GFP_KERNEL, "domain%d-pe%lx",
> +			domain_number, pe_num));
> +}
> +
>  void iommu_free_table(struct iommu_table *tbl, const char *node_name)
>  {
>  	unsigned long bitmap_sz;
>  	unsigned int order;
>  
> +	if (tbl && tbl->it_group) {
> +		iommu_group_put(tbl->it_group);
> +		BUG_ON(tbl->it_group);
> +	}
> +
>  	if (!tbl || !tbl->it_map) {
>  		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
>  				node_name);
> @@ -876,4 +906,317 @@ void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
>  {
>  }
>  
> +static enum dma_data_direction tce_direction(unsigned long tce)
> +{
> +	if ((tce & TCE_PCI_READ) && (tce & TCE_PCI_WRITE))
> +		return DMA_BIDIRECTIONAL;
> +	else if (tce & TCE_PCI_READ)
> +		return DMA_TO_DEVICE;
> +	else if (tce & TCE_PCI_WRITE)
> +		return DMA_FROM_DEVICE;
> +	else
> +		return DMA_NONE;
> +}
> +
> +void iommu_flush_tce(struct iommu_table *tbl)
> +{
> +	/* Flush/invalidate TLB caches if necessary */
> +	if (ppc_md.tce_flush)
> +		ppc_md.tce_flush(tbl);
> +
> +	/* Make sure updates are seen by hardware */
> +	mb();
> +}
> +EXPORT_SYMBOL_GPL(iommu_flush_tce);
> +
> +static long tce_clear_param_check(struct iommu_table *tbl,
> +		unsigned long ioba, unsigned long tce_value,
> +		unsigned long npages)
> +{
> +	unsigned long size = npages << IOMMU_PAGE_SHIFT;
> +
> +	/* ppc_md.tce_free() does not support any value but 0 */
> +	if (tce_value)
> +		return -EINVAL;
> +
> +	if (ioba & ~IOMMU_PAGE_MASK)
> +		return -EINVAL;
> +
> +	if ((ioba + size) > ((tbl->it_offset + tbl->it_size)
> +			<< IOMMU_PAGE_SHIFT))
> +		return -EINVAL;
> +
> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
> +		return -EINVAL;
> +
> +	return 0;

Why do these all return long (vs int)?  Is this a POWER-ism?

> +}
> +
> +static long 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 | TCE_PCI_WRITE | TCE_PCI_READ))
> +		return -EINVAL;
> +
> +	if (ioba & ~IOMMU_PAGE_MASK)
> +		return -EINVAL;
> +
> +	if ((ioba + IOMMU_PAGE_SIZE) > ((tbl->it_offset + tbl->it_size)
> +			<< IOMMU_PAGE_SHIFT))
> +		return -EINVAL;
> +
> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static long clear_tce(struct iommu_table *tbl,
> +		unsigned long entry, unsigned long pages)
> +{
> +	unsigned long oldtce;
> +	struct page *page;
> +	struct iommu_pool *pool;
> +
> +	for ( ; pages; --pages, ++entry) {
> +		pool = get_pool(tbl, entry);
> +		spin_lock(&(pool->lock));
> +
> +		oldtce = ppc_md.tce_get(tbl, entry);
> +		if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)) {
> +			ppc_md.tce_free(tbl, entry, 1);
> +
> +			page = pfn_to_page(oldtce >> PAGE_SHIFT);
> +			WARN_ON(!page);
> +			if (page) {
> +				if (oldtce & TCE_PCI_WRITE)
> +					SetPageDirty(page);
> +				put_page(page);
> +			}
> +		}
> +		spin_unlock(&(pool->lock));
> +	}
> +
> +	return 0;

No non-zero return, make it void?

> +}
> +
> +long iommu_clear_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
> +		unsigned long tce_value, unsigned long npages)
> +{
> +	long ret;
> +	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
> +
> +	ret = tce_clear_param_check(tbl, ioba, tce_value, npages);
> +	if (!ret)
> +		ret = clear_tce(tbl, entry, npages);
> +
> +	if (ret < 0)
> +		pr_err("iommu_tce: %s failed ioba=%lx, tce_value=%lx ret=%ld\n",
> +				__func__, ioba, tce_value, ret);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_clear_tce_user_mode);
> +
> +/* hwaddr is a virtual address here, tce_build converts it to physical */
> +static long do_tce_build(struct iommu_table *tbl, unsigned long entry,
> +		unsigned long hwaddr, enum dma_data_direction direction)
> +{
> +	long ret = -EBUSY;
> +	unsigned long oldtce;
> +	struct iommu_pool *pool = get_pool(tbl, entry);
> +
> +	spin_lock(&(pool->lock));
> +
> +	oldtce = ppc_md.tce_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);
> +
> +	spin_unlock(&(pool->lock));
> +
> +	if (unlikely(ret))
> +		pr_err("iommu_tce: %s failed on hwaddr=%lx ioba=%lx kva=%lx ret=%ld\n",
> +				__func__, hwaddr, entry << IOMMU_PAGE_SHIFT,
> +				hwaddr, ret);
> +
> +	return ret;
> +}
> +
> +static int put_tce_user_mode(struct iommu_table *tbl, unsigned long entry,
> +		unsigned long tce)
> +{
> +	int ret;

Now we're back to returning ints.

> +	struct page *page = NULL;
> +	unsigned long hwaddr, offset = tce & IOMMU_PAGE_MASK & ~PAGE_MASK;
> +	enum dma_data_direction direction = 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 << IOMMU_PAGE_SHIFT, ret);
> +		return -EFAULT;
> +	}
> +	hwaddr = (unsigned long) page_address(page) + offset;
> +
> +	ret = do_tce_build(tbl, entry, hwaddr, direction);
> +	if (ret)
> +		put_page(page);
> +
> +	return ret;
> +}
> +
> +long iommu_put_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
> +		unsigned long tce)
> +{
> +	long ret;

Oops, back to longs.

> +	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
> +
> +	ret = tce_put_param_check(tbl, ioba, tce);
> +	if (!ret)
> +		ret = put_tce_user_mode(tbl, entry, tce);
> +
> +	if (ret < 0)
> +		pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
> +				__func__, ioba, tce, ret);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
> +
> +/*
> + * Helpers to do locked pages accounting.
> + * Called from ioctl so down_write_trylock is not necessary.
> + */
> +static void lock_acct(long npage)
> +{
> +	if (!current->mm)
> +		return; /* process exited */
> +
> +	down_write(&current->mm->mmap_sem);
> +	current->mm->locked_vm += npage;
> +	up_write(&current->mm->mmap_sem);
> +}
> +
> +/*
> + * iommu_lock_table - Start/stop using the table by VFIO
> + * @tbl: Pointer to the IOMMU table
> + * @lock: true when VFIO starts using the table
> + */
> +long iommu_lock_table(struct iommu_table *tbl, bool lock)
> +{
> +	unsigned long sz = (tbl->it_size + 7) >> 3;
> +	unsigned long locked, lock_limit;
> +
> +	if (lock) {
> +		/*
> +		 * Account for locked pages
> +		 * The worst case is when every IOMMU page
> +		 * is mapped to separate system page
> +		 */
> +		locked = current->mm->locked_vm + tbl->it_size;
> +		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));
> +			return -ENOMEM;
> +		}
> +
> +		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;
> +		}
> +
> +		lock_acct(tbl->it_size);
> +		memset(tbl->it_map, 0xff, sz);
> +	}
> +
> +	/* Clear TCE table */
> +	clear_tce(tbl, tbl->it_offset, tbl->it_size);
> +
> +	if (!lock) {
> +		lock_acct(-tbl->it_size);
> +		memset(tbl->it_map, 0, sz);
> +
> +		/* Restore bit#0 set by iommu_init_table() */
> +		if (tbl->it_offset == 0)
> +			set_bit(0, tbl->it_map);
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(iommu_lock_table);
> +
> +int iommu_add_device(struct device *dev)
> +{
> +	struct iommu_table *tbl;
> +	int ret = 0;
> +
> +	if (WARN_ON(dev->iommu_group)) {
> +		pr_warn("iommu_tce: device %s is already in iommu group %d, skipping\n",
> +				dev_name(dev),
> +				iommu_group_id(dev->iommu_group));
> +		return -EBUSY;
> +	}
> +
> +	tbl = get_iommu_table_base(dev);
> +	if (!tbl) {
> +		pr_debug("iommu_tce: skipping device %s with no tbl\n",
> +				dev_name(dev));
> +		return 0;
> +	}
> +
> +	pr_debug("iommu_tce: adding %s to iommu group %d\n",
> +			dev_name(dev), iommu_group_id(tbl->it_group));
> +
> +	ret = iommu_group_add_device(tbl->it_group, dev);
> +	if (ret < 0)
> +		pr_err("iommu_tce: %s has not been added, ret=%d\n",
> +				dev_name(dev), ret);
> +
> +	return ret;
> +}
> +
> +void iommu_del_device(struct device *dev)
> +{
> +	iommu_group_remove_device(dev);
> +}
> +
> +static int iommu_bus_notifier(struct notifier_block *nb,
> +			      unsigned long action, void *data)
> +{
> +	struct device *dev = data;
> +
> +	switch (action) {
> +	case BUS_NOTIFY_ADD_DEVICE:
> +		return iommu_add_device(dev);
> +	case BUS_NOTIFY_DEL_DEVICE:
> +		iommu_del_device(dev);
> +		return 0;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static struct notifier_block tce_iommu_bus_nb = {
> +	.notifier_call = iommu_bus_notifier,
> +};
> +
> +static int __init tce_iommu_init(void)
> +{
> +	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
> +
> +	bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
> +	return 0;
> +}
> +
> +arch_initcall(tce_iommu_init);
> +
>  #endif /* CONFIG_IOMMU_API */
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 8e90e89..04dbc49 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -522,6 +522,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>  			| TCE_PCI_SWINV_PAIR;
>  	}
>  	iommu_init_table(tbl, phb->hose->node);
> +	iommu_register_group(tbl, pci_domain_nr(pe->pbus), pe->pe_number);
>  
>  	if (pe->pdev)
>  		set_iommu_table_base(&pe->pdev->dev, tbl);
> diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> index abe6780..7ce75b0 100644
> --- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> +++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> @@ -87,8 +87,11 @@ 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)
> +	if (phb->p5ioc2.iommu_table.it_map == NULL) {
>  		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);
> +	}
>  
>  	set_iommu_table_base(&pdev->dev, &phb->p5ioc2.iommu_table);
>  }
> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
> index f60a188..d112701 100644
> --- a/arch/powerpc/platforms/powernv/pci.c
> +++ b/arch/powerpc/platforms/powernv/pci.c
> @@ -20,6 +20,7 @@
>  #include <linux/irq.h>
>  #include <linux/io.h>
>  #include <linux/msi.h>
> +#include <linux/iommu.h>
>  
>  #include <asm/sections.h>
>  #include <asm/io.h>
> @@ -503,6 +504,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
>  	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
>  				  be32_to_cpup(sizep), 0);
>  	iommu_init_table(tbl, hose->node);
> +	iommu_register_group(tbl, 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",
> @@ -631,3 +633,4 @@ void __init pnv_pci_init(void)
>  	ppc_md.teardown_msi_irqs = pnv_teardown_msi_irqs;
>  #endif
>  }
> +

stray newline

> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index e39f9db..ce6b186 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -187,4 +187,12 @@ config EXYNOS_IOMMU_DEBUG
>  
>  	  Say N unless you need kernel log message for IOMMU debugging
>  
> +config SPAPR_TCE_IOMMU
> +	bool "sPAPR TCE IOMMU Support"
> +	depends on PPC_POWERNV
> +	select IOMMU_API
> +	help
> +	  Enables bits of IOMMU API required by VFIO. The iommu_ops is
> +	  still not implemented.
> +
>  endif # IOMMU_SUPPORT

Looks mostly ok to me other than the minor notes.  As mentioned
previously, this one needs to go in through power maintainers before I
can include 2/2 .  Thanks,

Alex

Re: [PATCH 2/2] vfio powerpc: implemented IOMMU driver for VFIO

[Alex Williamson]

On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
> VFIO implements platform independent stuff such as
> a PCI driver, BAR access (via read/write on a file descriptor
> or direct mapping when possible) and IRQ signaling.
> 
> The platform dependent part includes IOMMU initialization
> and handling. This patch implements an IOMMU driver for VFIO
> which does mapping/unmapping pages for the guest IO and
> provides information about DMA window (required by a POWERPC
> guest).
> 
> The counterpart in QEMU is required to support this functionality.

Revision info would be great here too.

> Cc: David Gibson <david@gibson.dropbear.id.au>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>  drivers/vfio/Kconfig                |    6 +
>  drivers/vfio/Makefile               |    1 +
>  drivers/vfio/vfio_iommu_spapr_tce.c |  269 +++++++++++++++++++++++++++++++++++
>  include/uapi/linux/vfio.h           |   31 ++++
>  4 files changed, 307 insertions(+)
>  create mode 100644 drivers/vfio/vfio_iommu_spapr_tce.c
> 
> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> index 7cd5dec..b464687 100644
> --- a/drivers/vfio/Kconfig
> +++ b/drivers/vfio/Kconfig
> @@ -3,10 +3,16 @@ config VFIO_IOMMU_TYPE1
>  	depends on VFIO
>  	default n
>  
> +config VFIO_IOMMU_SPAPR_TCE
> +	tristate
> +	depends on VFIO && SPAPR_TCE_IOMMU
> +	default n
> +
>  menuconfig VFIO
>  	tristate "VFIO Non-Privileged userspace driver framework"
>  	depends on IOMMU_API
>  	select VFIO_IOMMU_TYPE1 if X86
> +	select VFIO_IOMMU_SPAPR_TCE if PPC_POWERNV
>  	help
>  	  VFIO provides a framework for secure userspace device drivers.
>  	  See Documentation/vfio.txt for more details.
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index 2398d4a..72bfabc 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -1,3 +1,4 @@
>  obj-$(CONFIG_VFIO) += vfio.o
>  obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
> +obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
>  obj-$(CONFIG_VFIO_PCI) += pci/
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> new file mode 100644
> index 0000000..9b3fa88
> --- /dev/null
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -0,0 +1,269 @@
> +/*
> + * VFIO: IOMMU DMA mapping support for TCE on POWER
> + *
> + * Copyright (C) 2012 IBM Corp.  All rights reserved.

2013 now

> + *     Author: Alexey Kardashevskiy <aik@ozlabs.ru>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * Derived from original vfio_iommu_type1.c:
> + * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
> + *     Author: Alex Williamson <alex.williamson@redhat.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +#include <linux/err.h>
> +#include <linux/vfio.h>
> +#include <asm/iommu.h>
> +#include <asm/tce.h>
> +
> +#define DRIVER_VERSION  "0.1"
> +#define DRIVER_AUTHOR   "aik@ozlabs.ru"
> +#define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"
> +
> +static void tce_iommu_detach_group(void *iommu_data,
> +		struct iommu_group *iommu_group);
> +
> +/*
> + * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
> + *
> + * This code handles mapping and unmapping of user data buffers
> + * into DMA'ble space using the IOMMU
> + */
> +
> +/*
> + * The container descriptor supports only a single group per container.
> + * Required by the API as the container is not supplied with the IOMMU group
> + * at the moment of initialization.
> + */
> +struct tce_container {
> +	struct mutex lock;
> +	struct iommu_table *tbl;
> +};
> +
> +static void *tce_iommu_open(unsigned long arg)
> +{
> +	struct tce_container *container;
> +
> +	if (arg != VFIO_SPAPR_TCE_IOMMU) {
> +		pr_err("tce_vfio: Wrong IOMMU type\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	container = kzalloc(sizeof(*container), GFP_KERNEL);
> +	if (!container)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mutex_init(&container->lock);
> +
> +	return container;
> +}
> +
> +static void tce_iommu_release(void *iommu_data)
> +{
> +	struct tce_container *container = iommu_data;
> +
> +	WARN_ON(container->tbl && !container->tbl->it_group);
> +	if (container->tbl && container->tbl->it_group)
> +		tce_iommu_detach_group(iommu_data, container->tbl->it_group);
> +
> +	mutex_destroy(&container->lock);
> +
> +	kfree(container);
> +}
> +
> +static long tce_iommu_ioctl(void *iommu_data,
> +				 unsigned int cmd, unsigned long arg)
> +{
> +	struct tce_container *container = iommu_data;
> +	unsigned long minsz;
> +	long ret;
> +
> +	switch (cmd) {
> +	case VFIO_CHECK_EXTENSION:
> +		return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0;
> +
> +	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
> +		struct vfio_iommu_spapr_tce_info info;
> +		struct iommu_table *tbl = container->tbl;
> +
> +		if (WARN_ON(!tbl))
> +			return -ENXIO;
> +
> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
> +				dma32_window_size);
> +
> +		if (copy_from_user(&info, (void __user *)arg, minsz))
> +			return -EFAULT;
> +
> +		if (info.argsz < minsz)
> +			return -EINVAL;
> +
> +		info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT;
> +		info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT;
> +		info.flags = 0;
> +
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
> +
> +		return 0;
> +	}
> +	case VFIO_IOMMU_MAP_DMA: {
> +		vfio_iommu_spapr_tce_dma_map param;
> +		struct iommu_table *tbl = container->tbl;
> +		unsigned long tce;
> +
> +		if (WARN_ON(!tbl))
> +			return -ENXIO;
> +
> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_map, size);
> +
> +		if (copy_from_user(&param, (void __user *)arg, minsz))
> +			return -EFAULT;
> +
> +		if (param.argsz < minsz)
> +			return -EINVAL;
> +
> +		if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
> +				VFIO_DMA_MAP_FLAG_WRITE))
> +			return -EINVAL;
> +
> +		if ((param.size & ~IOMMU_PAGE_MASK) ||
> +				(param.vaddr & ~IOMMU_PAGE_MASK))
> +			return -EINVAL;
> +
> +		/* TODO: support multiple TCEs */
> +		if (param.size != IOMMU_PAGE_SIZE) {

Ouch, ioctl per page...

> +			pr_err("VFIO map on POWER supports only %lu page size\n",
> +					IOMMU_PAGE_SIZE);
> +			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;
> +
> +		ret = iommu_put_tce_user_mode(tbl, param.iova, tce);
> +		iommu_flush_tce(tbl);
> +
> +		return ret;
> +	}
> +	case VFIO_IOMMU_UNMAP_DMA: {
> +		vfio_iommu_spapr_tce_dma_unmap param;
> +		struct iommu_table *tbl = container->tbl;
> +
> +		if (WARN_ON(!tbl))
> +			return -ENXIO;
> +
> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_unmap, 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;
> +
> +		if (param.size & ~IOMMU_PAGE_MASK)
> +			return -EINVAL;

But you support multi-page unmaps?

> +
> +		/* iova is checked by the IOMMU API */
> +		ret = iommu_clear_tce_user_mode(tbl, param.iova, 0,
> +				param.size >> IOMMU_PAGE_SHIFT);
> +		iommu_flush_tce(tbl);
> +
> +		return ret;
> +	}
> +	}
> +
> +	return -ENOTTY;
> +}
> +
> +static int tce_iommu_attach_group(void *iommu_data,
> +		struct iommu_group *iommu_group)
> +{
> +	int ret;
> +	struct tce_container *container = iommu_data;
> +	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_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) {
> +		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(iommu_group));
> +		mutex_unlock(&container->lock);
> +		return -EBUSY;
> +	}
> +
> +	container->tbl = tbl;
> +	ret = iommu_lock_table(tbl, true);

Bug, container->tbl is set regardless of iommu_lock_table.

Ok, so now we're checking rlimits and handling page accounting on
VFIO_GROUP_SET_CONTAINER to avoid any overhead at map/unmap.  How can
the user learn tbl->it_size to set their locked page limit prior to
this?  It's available from GET_INFO, but there's a chicken and egg
problem that to get it there you have to get past this, which means
you're already ok.  Maybe it's in sysfs somewhere already or it could be
exposed in the iommu group like the name attribute.  Otherwise we might
consider doing locking on first mapping.  Thanks,

Alex

> +	mutex_unlock(&container->lock);
> +
> +	return ret;
> +}
> +
> +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);
> +
> +	BUG_ON(!tbl);
> +	mutex_lock(&container->lock);
> +	if (tbl != container->tbl) {
> +		pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
> +				iommu_group_id(iommu_group),
> +				iommu_group_id(tbl->it_group));
> +	} else {
> +
> +		pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
> +				iommu_group_id(iommu_group), iommu_group);
> +
> +		container->tbl = NULL;
> +		iommu_lock_table(tbl, false);
> +	}
> +	mutex_unlock(&container->lock);
> +}
> +
> +const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
> +	.name		= "iommu-vfio-powerpc",
> +	.owner		= THIS_MODULE,
> +	.open		= tce_iommu_open,
> +	.release	= tce_iommu_release,
> +	.ioctl		= tce_iommu_ioctl,
> +	.attach_group	= tce_iommu_attach_group,
> +	.detach_group	= tce_iommu_detach_group,
> +};
> +
> +static int __init tce_iommu_init(void)
> +{
> +	return vfio_register_iommu_driver(&tce_iommu_driver_ops);
> +}
> +
> +static void __exit tce_iommu_cleanup(void)
> +{
> +	vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
> +}
> +
> +module_init(tce_iommu_init);
> +module_exit(tce_iommu_cleanup);
> +
> +MODULE_VERSION(DRIVER_VERSION);
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR(DRIVER_AUTHOR);
> +MODULE_DESCRIPTION(DRIVER_DESC);
> +
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 4758d1b..ea9a9a7 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -22,6 +22,7 @@
>  /* Extensions */
>  
>  #define VFIO_TYPE1_IOMMU		1
> +#define VFIO_SPAPR_TCE_IOMMU		2
>  
>  /*
>   * The IOCTL interface is designed for extensibility by embedding the
> @@ -365,4 +366,34 @@ struct vfio_iommu_type1_dma_unmap {
>  
>  #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
>  
> +/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
> +
> +/*
> + * The SPAPR TCE info struct provides the information about the PCI bus
> + * address ranges available for DMA, these values are programmed into
> + * the hardware so the guest has to know that information.
> + *
> + * The DMA 32 bit window start is an absolute PCI bus address.
> + * The IOVA address passed via map/unmap ioctls are absolute PCI bus
> + * addresses too so the window works as a filter rather than an offset
> + * for IOVA addresses.
> + *
> + * A flag will need to be added if other page sizes are supported,
> + * so as defined here, it is always 4k.
> + */
> +struct vfio_iommu_spapr_tce_info {
> +	__u32 argsz;
> +	__u32 flags;			/* reserved for future use */
> +	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
> +	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
> +};
> +
> +#define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
> +
> +/* Reuse type1 map/unmap structs as they are the same at the moment */
> +typedef struct vfio_iommu_type1_dma_map vfio_iommu_spapr_tce_dma_map;
> +typedef struct vfio_iommu_type1_dma_unmap vfio_iommu_spapr_tce_dma_unmap;
> +
> +/* ***************************************************************** */
> +
>  #endif /* _UAPIVFIO_H */

Re: [PATCH 1/2] vfio powerpc: enabled on powernv platform

[Alexey Kardashevskiy]

On 12/02/13 09:16, Alex Williamson wrote:
> On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
>> This patch initializes IOMMU groups based on the IOMMU
>> configuration discovered during the PCI scan on POWERNV
>> (POWER non virtualized) platform. The IOMMU groups are
>> to be used later by VFIO driver (PCI pass through).
>>
>> It also implements an API for mapping/unmapping pages for
>> guest PCI drivers and providing DMA window properties.
>> This API is going to be used later by QEMU-VFIO to handle
>> h_put_tce hypercalls from the KVM guest.
>>
>> The iommu_put_tce_user_mode() does only a single page mapping
>> as an API for adding many mappings at once is going to be
>> added later.
>>
>> Although this driver has been tested only on the POWERNV
>> platform, it should work on any platform which supports
>> TCE tables. As h_put_tce hypercall is received by the host
>> kernel and processed by the QEMU (what involves calling
>> the host kernel again), performance is not the best -
>> circa 220MB/s on 10Gb ethernet network.
>>
>> To enable VFIO on POWER, enable SPAPR_TCE_IOMMU config
>> option and configure VFIO as required.
>>
>> Cc: David Gibson <david@gibson.dropbear.id.au>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>
> Yay, it's not dead! ;)

No, still alive :) I have been implementing real mode and multiple pages 
support (for real mode too) so I changed the interface a bit as I did not 
realize some bits from the powerpc arch.


> I'd love some kind of changelog to know what to look for in here,
> especially given 2mo since the last version.

There is no serious change actually.

>> ---
>>   arch/powerpc/include/asm/iommu.h            |   15 ++
>>   arch/powerpc/kernel/iommu.c                 |  343 +++++++++++++++++++++++++++
>>   arch/powerpc/platforms/powernv/pci-ioda.c   |    1 +
>>   arch/powerpc/platforms/powernv/pci-p5ioc2.c |    5 +-
>>   arch/powerpc/platforms/powernv/pci.c        |    3 +
>>   drivers/iommu/Kconfig                       |    8 +
>>   6 files changed, 374 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
>> index cbfe678..900294b 100644
>> --- a/arch/powerpc/include/asm/iommu.h
>> +++ b/arch/powerpc/include/asm/iommu.h
>> @@ -76,6 +76,9 @@ struct iommu_table {
>>   	struct iommu_pool large_pool;
>>   	struct iommu_pool pools[IOMMU_NR_POOLS];
>>   	unsigned long *it_map;       /* A simple allocation bitmap for now */
>> +#ifdef CONFIG_IOMMU_API
>> +	struct iommu_group *it_group;
>> +#endif
>>   };
>>
>>   struct scatterlist;
>> @@ -98,6 +101,8 @@ 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);
>> +extern void iommu_register_group(struct iommu_table * tbl,
>> +				 int domain_number, unsigned long pe_num);
>>
>>   extern int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
>>   			struct scatterlist *sglist, int nelems,
>> @@ -147,5 +152,15 @@ static inline void iommu_restore(void)
>>   }
>>   #endif
>>
>> +/* The API to support IOMMU operations for VFIO */
>> +extern long iommu_clear_tce_user_mode(struct iommu_table *tbl,
>> +		unsigned long ioba, unsigned long tce_value,
>> +		unsigned long npages);
>> +extern long iommu_put_tce_user_mode(struct iommu_table *tbl,
>> +		unsigned long ioba, unsigned long tce);
>> +
>> +extern void iommu_flush_tce(struct iommu_table *tbl);
>> +extern long iommu_lock_table(struct iommu_table *tbl, bool lock);
>> +
>>   #endif /* __KERNEL__ */
>>   #endif /* _ASM_IOMMU_H */
>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
>> index 7c309fe..b4fdabc 100644
>> --- a/arch/powerpc/kernel/iommu.c
>> +++ b/arch/powerpc/kernel/iommu.c
>> @@ -37,6 +37,7 @@
>>   #include <linux/fault-inject.h>
>>   #include <linux/pci.h>
>>   #include <linux/kvm_host.h>
>> +#include <linux/iommu.h>
>>   #include <asm/io.h>
>>   #include <asm/prom.h>
>>   #include <asm/iommu.h>
>> @@ -45,6 +46,7 @@
>>   #include <asm/kdump.h>
>>   #include <asm/fadump.h>
>>   #include <asm/vio.h>
>> +#include <asm/tce.h>
>>
>>   #define DBG(...)
>>
>> @@ -707,11 +709,39 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
>>   	return tbl;
>>   }
>>
>> +static void group_release(void *iommu_data)
>> +{
>> +	struct iommu_table *tbl = iommu_data;
>> +	tbl->it_group = NULL;
>> +}
>> +
>> +void iommu_register_group(struct iommu_table * tbl,
>> +		int domain_number, unsigned long pe_num)
>> +{
>> +	struct iommu_group *grp;
>> +
>> +	grp = iommu_group_alloc();
>> +	if (IS_ERR(grp)) {
>> +		pr_info("powerpc iommu api: cannot create new group, err=%ld\n",
>> +				PTR_ERR(grp));
>> +		return;
>> +	}
>> +	tbl->it_group = grp;
>> +	iommu_group_set_iommudata(grp, tbl, group_release);
>> +	iommu_group_set_name(grp, kasprintf(GFP_KERNEL, "domain%d-pe%lx",
>> +			domain_number, pe_num));
>> +}
>> +
>>   void iommu_free_table(struct iommu_table *tbl, const char *node_name)
>>   {
>>   	unsigned long bitmap_sz;
>>   	unsigned int order;
>>
>> +	if (tbl && tbl->it_group) {
>> +		iommu_group_put(tbl->it_group);
>> +		BUG_ON(tbl->it_group);
>> +	}
>> +
>>   	if (!tbl || !tbl->it_map) {
>>   		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
>>   				node_name);
>> @@ -876,4 +906,317 @@ void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
>>   {
>>   }
>>
>> +static enum dma_data_direction tce_direction(unsigned long tce)
>> +{
>> +	if ((tce & TCE_PCI_READ) && (tce & TCE_PCI_WRITE))
>> +		return DMA_BIDIRECTIONAL;
>> +	else if (tce & TCE_PCI_READ)
>> +		return DMA_TO_DEVICE;
>> +	else if (tce & TCE_PCI_WRITE)
>> +		return DMA_FROM_DEVICE;
>> +	else
>> +		return DMA_NONE;
>> +}
>> +
>> +void iommu_flush_tce(struct iommu_table *tbl)
>> +{
>> +	/* Flush/invalidate TLB caches if necessary */
>> +	if (ppc_md.tce_flush)
>> +		ppc_md.tce_flush(tbl);
>> +
>> +	/* Make sure updates are seen by hardware */
>> +	mb();
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_flush_tce);
>> +
>> +static long tce_clear_param_check(struct iommu_table *tbl,
>> +		unsigned long ioba, unsigned long tce_value,
>> +		unsigned long npages)
>> +{
>> +	unsigned long size = npages << IOMMU_PAGE_SHIFT;
>> +
>> +	/* ppc_md.tce_free() does not support any value but 0 */
>> +	if (tce_value)
>> +		return -EINVAL;
>> +
>> +	if (ioba & ~IOMMU_PAGE_MASK)
>> +		return -EINVAL;
>> +
>> +	if ((ioba + size) > ((tbl->it_offset + tbl->it_size)
>> +			<< IOMMU_PAGE_SHIFT))
>> +		return -EINVAL;
>> +
>> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
>> +		return -EINVAL;
>> +
>> +	return 0;
>
> Why do these all return long (vs int)?  Is this a POWER-ism?

No, not really but yeah, I picked it in powerpc code :) I tried to keep 
them "long" but I noticed "int" below so what is the rule? Change all to int?


>> +}
>> +
>> +static long 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 | TCE_PCI_WRITE | TCE_PCI_READ))
>> +		return -EINVAL;
>> +
>> +	if (ioba & ~IOMMU_PAGE_MASK)
>> +		return -EINVAL;
>> +
>> +	if ((ioba + IOMMU_PAGE_SIZE) > ((tbl->it_offset + tbl->it_size)
>> +			<< IOMMU_PAGE_SHIFT))
>> +		return -EINVAL;
>> +
>> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static long clear_tce(struct iommu_table *tbl,
>> +		unsigned long entry, unsigned long pages)
>> +{
>> +	unsigned long oldtce;
>> +	struct page *page;
>> +	struct iommu_pool *pool;
>> +
>> +	for ( ; pages; --pages, ++entry) {
>> +		pool = get_pool(tbl, entry);
>> +		spin_lock(&(pool->lock));
>> +
>> +		oldtce = ppc_md.tce_get(tbl, entry);
>> +		if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)) {
>> +			ppc_md.tce_free(tbl, entry, 1);
>> +
>> +			page = pfn_to_page(oldtce >> PAGE_SHIFT);
>> +			WARN_ON(!page);
>> +			if (page) {
>> +				if (oldtce & TCE_PCI_WRITE)
>> +					SetPageDirty(page);
>> +				put_page(page);
>> +			}
>> +		}
>> +		spin_unlock(&(pool->lock));
>> +	}
>> +
>> +	return 0;
>
> No non-zero return, make it void?

ah, ok. The prototype will change for real mode either way, it will get a 
"realmode" flag and become able to fail (which will switch the virtual mode).

>> +}
>> +
>> +long iommu_clear_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
>> +		unsigned long tce_value, unsigned long npages)
>> +{
>> +	long ret;
>> +	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
>> +
>> +	ret = tce_clear_param_check(tbl, ioba, tce_value, npages);
>> +	if (!ret)
>> +		ret = clear_tce(tbl, entry, npages);
>> +
>> +	if (ret < 0)
>> +		pr_err("iommu_tce: %s failed ioba=%lx, tce_value=%lx ret=%ld\n",
>> +				__func__, ioba, tce_value, ret);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_clear_tce_user_mode);
>> +
>> +/* hwaddr is a virtual address here, tce_build converts it to physical */
>> +static long do_tce_build(struct iommu_table *tbl, unsigned long entry,
>> +		unsigned long hwaddr, enum dma_data_direction direction)
>> +{
>> +	long ret = -EBUSY;
>> +	unsigned long oldtce;
>> +	struct iommu_pool *pool = get_pool(tbl, entry);
>> +
>> +	spin_lock(&(pool->lock));
>> +
>> +	oldtce = ppc_md.tce_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);
>> +
>> +	spin_unlock(&(pool->lock));
>> +
>> +	if (unlikely(ret))
>> +		pr_err("iommu_tce: %s failed on hwaddr=%lx ioba=%lx kva=%lx ret=%ld\n",
>> +				__func__, hwaddr, entry << IOMMU_PAGE_SHIFT,
>> +				hwaddr, ret);
>> +
>> +	return ret;
>> +}
>> +
>> +static int put_tce_user_mode(struct iommu_table *tbl, unsigned long entry,
>> +		unsigned long tce)
>> +{
>> +	int ret;
>
> Now we're back to returning ints.
 >
>> +	struct page *page = NULL;
>> +	unsigned long hwaddr, offset = tce & IOMMU_PAGE_MASK & ~PAGE_MASK;
>> +	enum dma_data_direction direction = 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 << IOMMU_PAGE_SHIFT, ret);
>> +		return -EFAULT;
>> +	}
>> +	hwaddr = (unsigned long) page_address(page) + offset;
>> +
>> +	ret = do_tce_build(tbl, entry, hwaddr, direction);
>> +	if (ret)
>> +		put_page(page);
>> +
>> +	return ret;
>> +}
>> +
>> +long iommu_put_tce_user_mode(struct iommu_table *tbl, unsigned long ioba,
>> +		unsigned long tce)
>> +{
>> +	long ret;
>
> Oops, back to longs.
>
>> +	unsigned long entry = ioba >> IOMMU_PAGE_SHIFT;
>> +
>> +	ret = tce_put_param_check(tbl, ioba, tce);
>> +	if (!ret)
>> +		ret = put_tce_user_mode(tbl, entry, tce);
>> +
>> +	if (ret < 0)
>> +		pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
>> +				__func__, ioba, tce, ret);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
>> +
>> +/*
>> + * Helpers to do locked pages accounting.
>> + * Called from ioctl so down_write_trylock is not necessary.
>> + */
>> +static void lock_acct(long npage)
>> +{
>> +	if (!current->mm)
>> +		return; /* process exited */
>> +
>> +	down_write(&current->mm->mmap_sem);
>> +	current->mm->locked_vm += npage;
>> +	up_write(&current->mm->mmap_sem);
>> +}
>> +
>> +/*
>> + * iommu_lock_table - Start/stop using the table by VFIO
>> + * @tbl: Pointer to the IOMMU table
>> + * @lock: true when VFIO starts using the table
>> + */
>> +long iommu_lock_table(struct iommu_table *tbl, bool lock)
>> +{
>> +	unsigned long sz = (tbl->it_size + 7) >> 3;
>> +	unsigned long locked, lock_limit;
>> +
>> +	if (lock) {
>> +		/*
>> +		 * Account for locked pages
>> +		 * The worst case is when every IOMMU page
>> +		 * is mapped to separate system page
>> +		 */
>> +		locked = current->mm->locked_vm + tbl->it_size;
>> +		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));
>> +			return -ENOMEM;
>> +		}
>> +
>> +		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;
>> +		}
>> +
>> +		lock_acct(tbl->it_size);
>> +		memset(tbl->it_map, 0xff, sz);
>> +	}
>> +
>> +	/* Clear TCE table */
>> +	clear_tce(tbl, tbl->it_offset, tbl->it_size);
>> +
>> +	if (!lock) {
>> +		lock_acct(-tbl->it_size);
>> +		memset(tbl->it_map, 0, sz);
>> +
>> +		/* Restore bit#0 set by iommu_init_table() */
>> +		if (tbl->it_offset == 0)
>> +			set_bit(0, tbl->it_map);
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_lock_table);
>> +
>> +int iommu_add_device(struct device *dev)
>> +{
>> +	struct iommu_table *tbl;
>> +	int ret = 0;
>> +
>> +	if (WARN_ON(dev->iommu_group)) {
>> +		pr_warn("iommu_tce: device %s is already in iommu group %d, skipping\n",
>> +				dev_name(dev),
>> +				iommu_group_id(dev->iommu_group));
>> +		return -EBUSY;
>> +	}
>> +
>> +	tbl = get_iommu_table_base(dev);
>> +	if (!tbl) {
>> +		pr_debug("iommu_tce: skipping device %s with no tbl\n",
>> +				dev_name(dev));
>> +		return 0;
>> +	}
>> +
>> +	pr_debug("iommu_tce: adding %s to iommu group %d\n",
>> +			dev_name(dev), iommu_group_id(tbl->it_group));
>> +
>> +	ret = iommu_group_add_device(tbl->it_group, dev);
>> +	if (ret < 0)
>> +		pr_err("iommu_tce: %s has not been added, ret=%d\n",
>> +				dev_name(dev), ret);
>> +
>> +	return ret;
>> +}
>> +
>> +void iommu_del_device(struct device *dev)
>> +{
>> +	iommu_group_remove_device(dev);
>> +}
>> +
>> +static int iommu_bus_notifier(struct notifier_block *nb,
>> +			      unsigned long action, void *data)
>> +{
>> +	struct device *dev = data;
>> +
>> +	switch (action) {
>> +	case BUS_NOTIFY_ADD_DEVICE:
>> +		return iommu_add_device(dev);
>> +	case BUS_NOTIFY_DEL_DEVICE:
>> +		iommu_del_device(dev);
>> +		return 0;
>> +	default:
>> +		return 0;
>> +	}
>> +}
>> +
>> +static struct notifier_block tce_iommu_bus_nb = {
>> +	.notifier_call = iommu_bus_notifier,
>> +};
>> +
>> +static int __init tce_iommu_init(void)
>> +{
>> +	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
>> +
>> +	bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
>> +	return 0;
>> +}
>> +
>> +arch_initcall(tce_iommu_init);
>> +
>>   #endif /* CONFIG_IOMMU_API */
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 8e90e89..04dbc49 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -522,6 +522,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
>>   			| TCE_PCI_SWINV_PAIR;
>>   	}
>>   	iommu_init_table(tbl, phb->hose->node);
>> +	iommu_register_group(tbl, pci_domain_nr(pe->pbus), pe->pe_number);
>>
>>   	if (pe->pdev)
>>   		set_iommu_table_base(&pe->pdev->dev, tbl);
>> diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> index abe6780..7ce75b0 100644
>> --- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> +++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
>> @@ -87,8 +87,11 @@ 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)
>> +	if (phb->p5ioc2.iommu_table.it_map == NULL) {
>>   		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);
>> +	}
>>
>>   	set_iommu_table_base(&pdev->dev, &phb->p5ioc2.iommu_table);
>>   }
>> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
>> index f60a188..d112701 100644
>> --- a/arch/powerpc/platforms/powernv/pci.c
>> +++ b/arch/powerpc/platforms/powernv/pci.c
>> @@ -20,6 +20,7 @@
>>   #include <linux/irq.h>
>>   #include <linux/io.h>
>>   #include <linux/msi.h>
>> +#include <linux/iommu.h>
>>
>>   #include <asm/sections.h>
>>   #include <asm/io.h>
>> @@ -503,6 +504,7 @@ static struct iommu_table *pnv_pci_setup_bml_iommu(struct pci_controller *hose)
>>   	pnv_pci_setup_iommu_table(tbl, __va(be64_to_cpup(basep)),
>>   				  be32_to_cpup(sizep), 0);
>>   	iommu_init_table(tbl, hose->node);
>> +	iommu_register_group(tbl, 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",
>> @@ -631,3 +633,4 @@ void __init pnv_pci_init(void)
>>   	ppc_md.teardown_msi_irqs = pnv_teardown_msi_irqs;
>>   #endif
>>   }
>> +
>
> stray newline
>
>> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
>> index e39f9db..ce6b186 100644
>> --- a/drivers/iommu/Kconfig
>> +++ b/drivers/iommu/Kconfig
>> @@ -187,4 +187,12 @@ config EXYNOS_IOMMU_DEBUG
>>
>>   	  Say N unless you need kernel log message for IOMMU debugging
>>
>> +config SPAPR_TCE_IOMMU
>> +	bool "sPAPR TCE IOMMU Support"
>> +	depends on PPC_POWERNV
>> +	select IOMMU_API
>> +	help
>> +	  Enables bits of IOMMU API required by VFIO. The iommu_ops is
>> +	  still not implemented.
>> +
>>   endif # IOMMU_SUPPORT
>
> Looks mostly ok to me other than the minor notes.  As mentioned
> previously, this one needs to go in through power maintainers before I
> can include 2/2 .  Thanks,
>
> Alex
>
>
>


-- 
Alexey

Re: [PATCH 2/2] vfio powerpc: implemented IOMMU driver for VFIO

[Alexey Kardashevskiy]

On 12/02/13 09:17, Alex Williamson wrote:
> On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
>> VFIO implements platform independent stuff such as
>> a PCI driver, BAR access (via read/write on a file descriptor
>> or direct mapping when possible) and IRQ signaling.
>>
>> The platform dependent part includes IOMMU initialization
>> and handling. This patch implements an IOMMU driver for VFIO
>> which does mapping/unmapping pages for the guest IO and
>> provides information about DMA window (required by a POWERPC
>> guest).
>>
>> The counterpart in QEMU is required to support this functionality.
>
> Revision info would be great here too.
 >
>
>> Cc: David Gibson <david@gibson.dropbear.id.au>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>>   drivers/vfio/Kconfig                |    6 +
>>   drivers/vfio/Makefile               |    1 +
>>   drivers/vfio/vfio_iommu_spapr_tce.c |  269 +++++++++++++++++++++++++++++++++++
>>   include/uapi/linux/vfio.h           |   31 ++++
>>   4 files changed, 307 insertions(+)
>>   create mode 100644 drivers/vfio/vfio_iommu_spapr_tce.c
>>
>> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
>> index 7cd5dec..b464687 100644
>> --- a/drivers/vfio/Kconfig
>> +++ b/drivers/vfio/Kconfig
>> @@ -3,10 +3,16 @@ config VFIO_IOMMU_TYPE1
>>   	depends on VFIO
>>   	default n
>>
>> +config VFIO_IOMMU_SPAPR_TCE
>> +	tristate
>> +	depends on VFIO && SPAPR_TCE_IOMMU
>> +	default n
>> +
>>   menuconfig VFIO
>>   	tristate "VFIO Non-Privileged userspace driver framework"
>>   	depends on IOMMU_API
>>   	select VFIO_IOMMU_TYPE1 if X86
>> +	select VFIO_IOMMU_SPAPR_TCE if PPC_POWERNV
>>   	help
>>   	  VFIO provides a framework for secure userspace device drivers.
>>   	  See Documentation/vfio.txt for more details.
>> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
>> index 2398d4a..72bfabc 100644
>> --- a/drivers/vfio/Makefile
>> +++ b/drivers/vfio/Makefile
>> @@ -1,3 +1,4 @@
>>   obj-$(CONFIG_VFIO) += vfio.o
>>   obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
>> +obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
>>   obj-$(CONFIG_VFIO_PCI) += pci/
>> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
>> new file mode 100644
>> index 0000000..9b3fa88
>> --- /dev/null
>> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
>> @@ -0,0 +1,269 @@
>> +/*
>> + * VFIO: IOMMU DMA mapping support for TCE on POWER
>> + *
>> + * Copyright (C) 2012 IBM Corp.  All rights reserved.
>
> 2013 now
>
>> + *     Author: Alexey Kardashevskiy <aik@ozlabs.ru>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * Derived from original vfio_iommu_type1.c:
>> + * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
>> + *     Author: Alex Williamson <alex.williamson@redhat.com>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/pci.h>
>> +#include <linux/slab.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/err.h>
>> +#include <linux/vfio.h>
>> +#include <asm/iommu.h>
>> +#include <asm/tce.h>
>> +
>> +#define DRIVER_VERSION  "0.1"
>> +#define DRIVER_AUTHOR   "aik@ozlabs.ru"
>> +#define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"
>> +
>> +static void tce_iommu_detach_group(void *iommu_data,
>> +		struct iommu_group *iommu_group);
>> +
>> +/*
>> + * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
>> + *
>> + * This code handles mapping and unmapping of user data buffers
>> + * into DMA'ble space using the IOMMU
>> + */
>> +
>> +/*
>> + * The container descriptor supports only a single group per container.
>> + * Required by the API as the container is not supplied with the IOMMU group
>> + * at the moment of initialization.
>> + */
>> +struct tce_container {
>> +	struct mutex lock;
>> +	struct iommu_table *tbl;
>> +};
>> +
>> +static void *tce_iommu_open(unsigned long arg)
>> +{
>> +	struct tce_container *container;
>> +
>> +	if (arg != VFIO_SPAPR_TCE_IOMMU) {
>> +		pr_err("tce_vfio: Wrong IOMMU type\n");
>> +		return ERR_PTR(-EINVAL);
>> +	}
>> +
>> +	container = kzalloc(sizeof(*container), GFP_KERNEL);
>> +	if (!container)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mutex_init(&container->lock);
>> +
>> +	return container;
>> +}
>> +
>> +static void tce_iommu_release(void *iommu_data)
>> +{
>> +	struct tce_container *container = iommu_data;
>> +
>> +	WARN_ON(container->tbl && !container->tbl->it_group);
>> +	if (container->tbl && container->tbl->it_group)
>> +		tce_iommu_detach_group(iommu_data, container->tbl->it_group);
>> +
>> +	mutex_destroy(&container->lock);
>> +
>> +	kfree(container);
>> +}
>> +
>> +static long tce_iommu_ioctl(void *iommu_data,
>> +				 unsigned int cmd, unsigned long arg)
>> +{
>> +	struct tce_container *container = iommu_data;
>> +	unsigned long minsz;
>> +	long ret;
>> +
>> +	switch (cmd) {
>> +	case VFIO_CHECK_EXTENSION:
>> +		return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0;
>> +
>> +	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
>> +		struct vfio_iommu_spapr_tce_info info;
>> +		struct iommu_table *tbl = container->tbl;
>> +
>> +		if (WARN_ON(!tbl))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
>> +				dma32_window_size);
>> +
>> +		if (copy_from_user(&info, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (info.argsz < minsz)
>> +			return -EINVAL;
>> +
>> +		info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT;
>> +		info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT;
>> +		info.flags = 0;
>> +
>> +		if (copy_to_user((void __user *)arg, &info, minsz))
>> +			return -EFAULT;
>> +
>> +		return 0;
>> +	}
>> +	case VFIO_IOMMU_MAP_DMA: {
>> +		vfio_iommu_spapr_tce_dma_map param;
>> +		struct iommu_table *tbl = container->tbl;
>> +		unsigned long tce;
>> +
>> +		if (WARN_ON(!tbl))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_map, size);
>> +
>> +		if (copy_from_user(&param, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (param.argsz < minsz)
>> +			return -EINVAL;
>> +
>> +		if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
>> +				VFIO_DMA_MAP_FLAG_WRITE))
>> +			return -EINVAL;
>> +
>> +		if ((param.size & ~IOMMU_PAGE_MASK) ||
>> +				(param.vaddr & ~IOMMU_PAGE_MASK))
>> +			return -EINVAL;
>> +
>> +		/* TODO: support multiple TCEs */
>> +		if (param.size != IOMMU_PAGE_SIZE) {
>
> Ouch, ioctl per page...

Well, there is something to discuss.

On POWER, there is an interface to add multiple pages at once but the guest 
does not supply the range of guest phys addresses, it puts some addresses 
to a small page (so it is up to 512 pages at once) and passes this address 
to the host as a parameter.

I posted another series yesterday but forgot to cc: you :) You can find 
them here - http://patchwork.ozlabs.org/patch/219592/ (emulated devices) 
and http://patchwork.ozlabs.org/patch/219594/ (vfio). There I convert guest 
phys address (real and virtual mode are handled different ways) and call 
iommu_put_tce_user_mode() (or analog) in a loop.

Either way, I did some tests with 10Gb card and without real mode stuff it 
does 220MB/s, and even if I do multi-tce it won't be faster than ~400MB/s 
which is still not enough as the real mode code makes it 1020MB/s. Slower 
devices work on the same speed no matter what.


>> +			pr_err("VFIO map on POWER supports only %lu page size\n",
>> +					IOMMU_PAGE_SIZE);
>> +			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;
>> +
>> +		ret = iommu_put_tce_user_mode(tbl, param.iova, tce);
>> +		iommu_flush_tce(tbl);
>> +
>> +		return ret;
>> +	}
>> +	case VFIO_IOMMU_UNMAP_DMA: {
>> +		vfio_iommu_spapr_tce_dma_unmap param;
>> +		struct iommu_table *tbl = container->tbl;
>> +
>> +		if (WARN_ON(!tbl))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_unmap, 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;
>> +
>> +		if (param.size & ~IOMMU_PAGE_MASK)
>> +			return -EINVAL;
>
> But you support multi-page unmaps?

Yes, this is a lot easier :)


>> +		/* iova is checked by the IOMMU API */
>> +		ret = iommu_clear_tce_user_mode(tbl, param.iova, 0,
>> +				param.size >> IOMMU_PAGE_SHIFT);
>> +		iommu_flush_tce(tbl);
>> +
>> +		return ret;
>> +	}
>> +	}
>> +
>> +	return -ENOTTY;
>> +}
>> +
>> +static int tce_iommu_attach_group(void *iommu_data,
>> +		struct iommu_group *iommu_group)
>> +{
>> +	int ret;
>> +	struct tce_container *container = iommu_data;
>> +	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_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) {
>> +		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(iommu_group));
>> +		mutex_unlock(&container->lock);
>> +		return -EBUSY;
>> +	}
>> +
>> +	container->tbl = tbl;
>> +	ret = iommu_lock_table(tbl, true);
>
> Bug, container->tbl is set regardless of iommu_lock_table.

Oops, bug.

> Ok, so now we're checking rlimits and handling page accounting on
> VFIO_GROUP_SET_CONTAINER to avoid any overhead at map/unmap.  How can
> the user learn tbl->it_size to set their locked page limit prior to
> this?  It's available from GET_INFO, but there's a chicken and egg
> problem that to get it there you have to get past this, which means
> you're already ok.  Maybe it's in sysfs somewhere already or it could be
> exposed in the iommu group like the name attribute.  Otherwise we might
> consider doing locking on first mapping.  Thanks,

GET_INFO is called in the beginning so QEMU will exit right there. No real 
work will have been done till that moment so what is the problem?



> Alex
>
>> +	mutex_unlock(&container->lock);
>> +
>> +	return ret;
>> +}
>> +
>> +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);
>> +
>> +	BUG_ON(!tbl);
>> +	mutex_lock(&container->lock);
>> +	if (tbl != container->tbl) {
>> +		pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
>> +				iommu_group_id(iommu_group),
>> +				iommu_group_id(tbl->it_group));
>> +	} else {
>> +
>> +		pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
>> +				iommu_group_id(iommu_group), iommu_group);
>> +
>> +		container->tbl = NULL;
>> +		iommu_lock_table(tbl, false);
>> +	}
>> +	mutex_unlock(&container->lock);
>> +}
>> +
>> +const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
>> +	.name		= "iommu-vfio-powerpc",
>> +	.owner		= THIS_MODULE,
>> +	.open		= tce_iommu_open,
>> +	.release	= tce_iommu_release,
>> +	.ioctl		= tce_iommu_ioctl,
>> +	.attach_group	= tce_iommu_attach_group,
>> +	.detach_group	= tce_iommu_detach_group,
>> +};
>> +
>> +static int __init tce_iommu_init(void)
>> +{
>> +	return vfio_register_iommu_driver(&tce_iommu_driver_ops);
>> +}
>> +
>> +static void __exit tce_iommu_cleanup(void)
>> +{
>> +	vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
>> +}
>> +
>> +module_init(tce_iommu_init);
>> +module_exit(tce_iommu_cleanup);
>> +
>> +MODULE_VERSION(DRIVER_VERSION);
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR(DRIVER_AUTHOR);
>> +MODULE_DESCRIPTION(DRIVER_DESC);
>> +
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index 4758d1b..ea9a9a7 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -22,6 +22,7 @@
>>   /* Extensions */
>>
>>   #define VFIO_TYPE1_IOMMU		1
>> +#define VFIO_SPAPR_TCE_IOMMU		2
>>
>>   /*
>>    * The IOCTL interface is designed for extensibility by embedding the
>> @@ -365,4 +366,34 @@ struct vfio_iommu_type1_dma_unmap {
>>
>>   #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
>>
>> +/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>> +
>> +/*
>> + * The SPAPR TCE info struct provides the information about the PCI bus
>> + * address ranges available for DMA, these values are programmed into
>> + * the hardware so the guest has to know that information.
>> + *
>> + * The DMA 32 bit window start is an absolute PCI bus address.
>> + * The IOVA address passed via map/unmap ioctls are absolute PCI bus
>> + * addresses too so the window works as a filter rather than an offset
>> + * for IOVA addresses.
>> + *
>> + * A flag will need to be added if other page sizes are supported,
>> + * so as defined here, it is always 4k.
>> + */
>> +struct vfio_iommu_spapr_tce_info {
>> +	__u32 argsz;
>> +	__u32 flags;			/* reserved for future use */
>> +	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
>> +	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
>> +};
>> +
>> +#define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
>> +
>> +/* Reuse type1 map/unmap structs as they are the same at the moment */
>> +typedef struct vfio_iommu_type1_dma_map vfio_iommu_spapr_tce_dma_map;
>> +typedef struct vfio_iommu_type1_dma_unmap vfio_iommu_spapr_tce_dma_unmap;
>> +
>> +/* ***************************************************************** */
>> +
>>   #endif /* _UAPIVFIO_H */
>
>
>


-- 
Alexey

Re: [PATCH 1/2] vfio powerpc: enabled on powernv platform

[Alex Williamson]

On Tue, 2013-02-12 at 10:19 +1100, Alexey Kardashevskiy wrote:
> On 12/02/13 09:16, Alex Williamson wrote:
> > On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
> >> @@ -707,11 +709,39 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
> >>   	return tbl;
> >>   }
> >>
> >> +static void group_release(void *iommu_data)
> >> +{
> >> +	struct iommu_table *tbl = iommu_data;
> >> +	tbl->it_group = NULL;
> >> +}
> >> +
> >> +void iommu_register_group(struct iommu_table * tbl,
> >> +		int domain_number, unsigned long pe_num)
> >> +{
> >> +	struct iommu_group *grp;
> >> +
> >> +	grp = iommu_group_alloc();
> >> +	if (IS_ERR(grp)) {
> >> +		pr_info("powerpc iommu api: cannot create new group, err=%ld\n",
> >> +				PTR_ERR(grp));
> >> +		return;
> >> +	}
> >> +	tbl->it_group = grp;
> >> +	iommu_group_set_iommudata(grp, tbl, group_release);
> >> +	iommu_group_set_name(grp, kasprintf(GFP_KERNEL, "domain%d-pe%lx",
> >> +			domain_number, pe_num));
> >> +}
> >> +
> >>   void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> >>   {
> >>   	unsigned long bitmap_sz;
> >>   	unsigned int order;
> >>
> >> +	if (tbl && tbl->it_group) {
> >> +		iommu_group_put(tbl->it_group);
> >> +		BUG_ON(tbl->it_group);
> >> +	}
> >> +
> >>   	if (!tbl || !tbl->it_map) {
> >>   		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
> >>   				node_name);
> >> @@ -876,4 +906,317 @@ void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
> >>   {
> >>   }
> >>
> >> +static enum dma_data_direction tce_direction(unsigned long tce)
> >> +{
> >> +	if ((tce & TCE_PCI_READ) && (tce & TCE_PCI_WRITE))
> >> +		return DMA_BIDIRECTIONAL;
> >> +	else if (tce & TCE_PCI_READ)
> >> +		return DMA_TO_DEVICE;
> >> +	else if (tce & TCE_PCI_WRITE)
> >> +		return DMA_FROM_DEVICE;
> >> +	else
> >> +		return DMA_NONE;
> >> +}
> >> +
> >> +void iommu_flush_tce(struct iommu_table *tbl)
> >> +{
> >> +	/* Flush/invalidate TLB caches if necessary */
> >> +	if (ppc_md.tce_flush)
> >> +		ppc_md.tce_flush(tbl);
> >> +
> >> +	/* Make sure updates are seen by hardware */
> >> +	mb();
> >> +}
> >> +EXPORT_SYMBOL_GPL(iommu_flush_tce);
> >> +
> >> +static long tce_clear_param_check(struct iommu_table *tbl,
> >> +		unsigned long ioba, unsigned long tce_value,
> >> +		unsigned long npages)
> >> +{
> >> +	unsigned long size = npages << IOMMU_PAGE_SHIFT;
> >> +
> >> +	/* ppc_md.tce_free() does not support any value but 0 */
> >> +	if (tce_value)
> >> +		return -EINVAL;
> >> +
> >> +	if (ioba & ~IOMMU_PAGE_MASK)
> >> +		return -EINVAL;
> >> +
> >> +	if ((ioba + size) > ((tbl->it_offset + tbl->it_size)
> >> +			<< IOMMU_PAGE_SHIFT))
> >> +		return -EINVAL;
> >> +
> >> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
> >> +		return -EINVAL;
> >> +
> >> +	return 0;
> >
> > Why do these all return long (vs int)?  Is this a POWER-ism?
> 
> No, not really but yeah, I picked it in powerpc code :) I tried to keep 
> them "long" but I noticed "int" below so what is the rule? Change all to int?

I'd say anything that's returning 0/-errno should probably be an int.

> >> +}
> >> +
> >> +static long 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 | TCE_PCI_WRITE | TCE_PCI_READ))
> >> +		return -EINVAL;
> >> +
> >> +	if (ioba & ~IOMMU_PAGE_MASK)
> >> +		return -EINVAL;
> >> +
> >> +	if ((ioba + IOMMU_PAGE_SIZE) > ((tbl->it_offset + tbl->it_size)
> >> +			<< IOMMU_PAGE_SHIFT))
> >> +		return -EINVAL;
> >> +
> >> +	if (ioba < (tbl->it_offset << IOMMU_PAGE_SHIFT))
> >> +		return -EINVAL;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static long clear_tce(struct iommu_table *tbl,
> >> +		unsigned long entry, unsigned long pages)
> >> +{
> >> +	unsigned long oldtce;
> >> +	struct page *page;
> >> +	struct iommu_pool *pool;
> >> +
> >> +	for ( ; pages; --pages, ++entry) {
> >> +		pool = get_pool(tbl, entry);
> >> +		spin_lock(&(pool->lock));
> >> +
> >> +		oldtce = ppc_md.tce_get(tbl, entry);
> >> +		if (oldtce & (TCE_PCI_WRITE | TCE_PCI_READ)) {
> >> +			ppc_md.tce_free(tbl, entry, 1);
> >> +
> >> +			page = pfn_to_page(oldtce >> PAGE_SHIFT);
> >> +			WARN_ON(!page);
> >> +			if (page) {
> >> +				if (oldtce & TCE_PCI_WRITE)
> >> +					SetPageDirty(page);
> >> +				put_page(page);
> >> +			}
> >> +		}
> >> +		spin_unlock(&(pool->lock));
> >> +	}
> >> +
> >> +	return 0;
> >
> > No non-zero return, make it void?
> 
> ah, ok. The prototype will change for real mode either way, it will get a 
> "realmode" flag and become able to fail (which will switch the virtual mode).

If you'll use it later on, no need to change it for me.  Thanks,

Alex

Re: [PATCH 2/2] vfio powerpc: implemented IOMMU driver for VFIO

[Alex Williamson]

On Tue, 2013-02-12 at 10:45 +1100, Alexey Kardashevskiy wrote:
> On 12/02/13 09:17, Alex Williamson wrote:
> > On Mon, 2013-02-11 at 22:54 +1100, Alexey Kardashevskiy wrote:
> >> VFIO implements platform independent stuff such as
> >> a PCI driver, BAR access (via read/write on a file descriptor
> >> or direct mapping when possible) and IRQ signaling.
> >>
> >> The platform dependent part includes IOMMU initialization
> >> and handling. This patch implements an IOMMU driver for VFIO
> >> which does mapping/unmapping pages for the guest IO and
> >> provides information about DMA window (required by a POWERPC
> >> guest).
> >>
> >> The counterpart in QEMU is required to support this functionality.
> >
> > Revision info would be great here too.
>  >
> >
> >> Cc: David Gibson <david@gibson.dropbear.id.au>
> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> >> ---
> >>   drivers/vfio/Kconfig                |    6 +
> >>   drivers/vfio/Makefile               |    1 +
> >>   drivers/vfio/vfio_iommu_spapr_tce.c |  269 +++++++++++++++++++++++++++++++++++
> >>   include/uapi/linux/vfio.h           |   31 ++++
> >>   4 files changed, 307 insertions(+)
> >>   create mode 100644 drivers/vfio/vfio_iommu_spapr_tce.c
> >>
> >> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> >> index 7cd5dec..b464687 100644
> >> --- a/drivers/vfio/Kconfig
> >> +++ b/drivers/vfio/Kconfig
> >> @@ -3,10 +3,16 @@ config VFIO_IOMMU_TYPE1
> >>   	depends on VFIO
> >>   	default n
> >>
> >> +config VFIO_IOMMU_SPAPR_TCE
> >> +	tristate
> >> +	depends on VFIO && SPAPR_TCE_IOMMU
> >> +	default n
> >> +
> >>   menuconfig VFIO
> >>   	tristate "VFIO Non-Privileged userspace driver framework"
> >>   	depends on IOMMU_API
> >>   	select VFIO_IOMMU_TYPE1 if X86
> >> +	select VFIO_IOMMU_SPAPR_TCE if PPC_POWERNV
> >>   	help
> >>   	  VFIO provides a framework for secure userspace device drivers.
> >>   	  See Documentation/vfio.txt for more details.
> >> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> >> index 2398d4a..72bfabc 100644
> >> --- a/drivers/vfio/Makefile
> >> +++ b/drivers/vfio/Makefile
> >> @@ -1,3 +1,4 @@
> >>   obj-$(CONFIG_VFIO) += vfio.o
> >>   obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
> >> +obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
> >>   obj-$(CONFIG_VFIO_PCI) += pci/
> >> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> >> new file mode 100644
> >> index 0000000..9b3fa88
> >> --- /dev/null
> >> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> >> @@ -0,0 +1,269 @@
> >> +/*
> >> + * VFIO: IOMMU DMA mapping support for TCE on POWER
> >> + *
> >> + * Copyright (C) 2012 IBM Corp.  All rights reserved.
> >
> > 2013 now
> >
> >> + *     Author: Alexey Kardashevskiy <aik@ozlabs.ru>
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License version 2 as
> >> + * published by the Free Software Foundation.
> >> + *
> >> + * Derived from original vfio_iommu_type1.c:
> >> + * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
> >> + *     Author: Alex Williamson <alex.williamson@redhat.com>
> >> + */
> >> +
> >> +#include <linux/module.h>
> >> +#include <linux/pci.h>
> >> +#include <linux/slab.h>
> >> +#include <linux/uaccess.h>
> >> +#include <linux/err.h>
> >> +#include <linux/vfio.h>
> >> +#include <asm/iommu.h>
> >> +#include <asm/tce.h>
> >> +
> >> +#define DRIVER_VERSION  "0.1"
> >> +#define DRIVER_AUTHOR   "aik@ozlabs.ru"
> >> +#define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"
> >> +
> >> +static void tce_iommu_detach_group(void *iommu_data,
> >> +		struct iommu_group *iommu_group);
> >> +
> >> +/*
> >> + * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
> >> + *
> >> + * This code handles mapping and unmapping of user data buffers
> >> + * into DMA'ble space using the IOMMU
> >> + */
> >> +
> >> +/*
> >> + * The container descriptor supports only a single group per container.
> >> + * Required by the API as the container is not supplied with the IOMMU group
> >> + * at the moment of initialization.
> >> + */
> >> +struct tce_container {
> >> +	struct mutex lock;
> >> +	struct iommu_table *tbl;
> >> +};
> >> +
> >> +static void *tce_iommu_open(unsigned long arg)
> >> +{
> >> +	struct tce_container *container;
> >> +
> >> +	if (arg != VFIO_SPAPR_TCE_IOMMU) {
> >> +		pr_err("tce_vfio: Wrong IOMMU type\n");
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> >> +
> >> +	container = kzalloc(sizeof(*container), GFP_KERNEL);
> >> +	if (!container)
> >> +		return ERR_PTR(-ENOMEM);
> >> +
> >> +	mutex_init(&container->lock);
> >> +
> >> +	return container;
> >> +}
> >> +
> >> +static void tce_iommu_release(void *iommu_data)
> >> +{
> >> +	struct tce_container *container = iommu_data;
> >> +
> >> +	WARN_ON(container->tbl && !container->tbl->it_group);
> >> +	if (container->tbl && container->tbl->it_group)
> >> +		tce_iommu_detach_group(iommu_data, container->tbl->it_group);
> >> +
> >> +	mutex_destroy(&container->lock);
> >> +
> >> +	kfree(container);
> >> +}
> >> +
> >> +static long tce_iommu_ioctl(void *iommu_data,
> >> +				 unsigned int cmd, unsigned long arg)
> >> +{
> >> +	struct tce_container *container = iommu_data;
> >> +	unsigned long minsz;
> >> +	long ret;
> >> +
> >> +	switch (cmd) {
> >> +	case VFIO_CHECK_EXTENSION:
> >> +		return (arg == VFIO_SPAPR_TCE_IOMMU) ? 1 : 0;
> >> +
> >> +	case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
> >> +		struct vfio_iommu_spapr_tce_info info;
> >> +		struct iommu_table *tbl = container->tbl;
> >> +
> >> +		if (WARN_ON(!tbl))
> >> +			return -ENXIO;
> >> +
> >> +		minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
> >> +				dma32_window_size);
> >> +
> >> +		if (copy_from_user(&info, (void __user *)arg, minsz))
> >> +			return -EFAULT;
> >> +
> >> +		if (info.argsz < minsz)
> >> +			return -EINVAL;
> >> +
> >> +		info.dma32_window_start = tbl->it_offset << IOMMU_PAGE_SHIFT;
> >> +		info.dma32_window_size = tbl->it_size << IOMMU_PAGE_SHIFT;
> >> +		info.flags = 0;
> >> +
> >> +		if (copy_to_user((void __user *)arg, &info, minsz))
> >> +			return -EFAULT;
> >> +
> >> +		return 0;
> >> +	}
> >> +	case VFIO_IOMMU_MAP_DMA: {
> >> +		vfio_iommu_spapr_tce_dma_map param;
> >> +		struct iommu_table *tbl = container->tbl;
> >> +		unsigned long tce;
> >> +
> >> +		if (WARN_ON(!tbl))
> >> +			return -ENXIO;
> >> +
> >> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_map, size);
> >> +
> >> +		if (copy_from_user(&param, (void __user *)arg, minsz))
> >> +			return -EFAULT;
> >> +
> >> +		if (param.argsz < minsz)
> >> +			return -EINVAL;
> >> +
> >> +		if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
> >> +				VFIO_DMA_MAP_FLAG_WRITE))
> >> +			return -EINVAL;
> >> +
> >> +		if ((param.size & ~IOMMU_PAGE_MASK) ||
> >> +				(param.vaddr & ~IOMMU_PAGE_MASK))
> >> +			return -EINVAL;
> >> +
> >> +		/* TODO: support multiple TCEs */
> >> +		if (param.size != IOMMU_PAGE_SIZE) {
> >
> > Ouch, ioctl per page...
> 
> Well, there is something to discuss.
> 
> On POWER, there is an interface to add multiple pages at once but the guest 
> does not supply the range of guest phys addresses, it puts some addresses 
> to a small page (so it is up to 512 pages at once) and passes this address 
> to the host as a parameter.
> 
> I posted another series yesterday but forgot to cc: you :) You can find 
> them here - http://patchwork.ozlabs.org/patch/219592/ (emulated devices) 
> and http://patchwork.ozlabs.org/patch/219594/ (vfio). There I convert guest 
> phys address (real and virtual mode are handled different ways) and call 
> iommu_put_tce_user_mode() (or analog) in a loop.
> 
> Either way, I did some tests with 10Gb card and without real mode stuff it 
> does 220MB/s, and even if I do multi-tce it won't be faster than ~400MB/s 
> which is still not enough as the real mode code makes it 1020MB/s. Slower 
> devices work on the same speed no matter what.

Ok, I'll take a look.

> >> +			pr_err("VFIO map on POWER supports only %lu page size\n",
> >> +					IOMMU_PAGE_SIZE);
> >> +			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;
> >> +
> >> +		ret = iommu_put_tce_user_mode(tbl, param.iova, tce);
> >> +		iommu_flush_tce(tbl);
> >> +
> >> +		return ret;
> >> +	}
> >> +	case VFIO_IOMMU_UNMAP_DMA: {
> >> +		vfio_iommu_spapr_tce_dma_unmap param;
> >> +		struct iommu_table *tbl = container->tbl;
> >> +
> >> +		if (WARN_ON(!tbl))
> >> +			return -ENXIO;
> >> +
> >> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_unmap, 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;
> >> +
> >> +		if (param.size & ~IOMMU_PAGE_MASK)
> >> +			return -EINVAL;
> >
> > But you support multi-page unmaps?
> 
> Yes, this is a lot easier :)
> 
> 
> >> +		/* iova is checked by the IOMMU API */
> >> +		ret = iommu_clear_tce_user_mode(tbl, param.iova, 0,
> >> +				param.size >> IOMMU_PAGE_SHIFT);
> >> +		iommu_flush_tce(tbl);
> >> +
> >> +		return ret;
> >> +	}
> >> +	}
> >> +
> >> +	return -ENOTTY;
> >> +}
> >> +
> >> +static int tce_iommu_attach_group(void *iommu_data,
> >> +		struct iommu_group *iommu_group)
> >> +{
> >> +	int ret;
> >> +	struct tce_container *container = iommu_data;
> >> +	struct iommu_table *tbl = iommu_group_get_iommudata(iommu_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) {
> >> +		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(iommu_group));
> >> +		mutex_unlock(&container->lock);
> >> +		return -EBUSY;
> >> +	}
> >> +
> >> +	container->tbl = tbl;
> >> +	ret = iommu_lock_table(tbl, true);
> >
> > Bug, container->tbl is set regardless of iommu_lock_table.
> 
> Oops, bug.
> 
> > Ok, so now we're checking rlimits and handling page accounting on
> > VFIO_GROUP_SET_CONTAINER to avoid any overhead at map/unmap.  How can
> > the user learn tbl->it_size to set their locked page limit prior to
> > this?  It's available from GET_INFO, but there's a chicken and egg
> > problem that to get it there you have to get past this, which means
> > you're already ok.  Maybe it's in sysfs somewhere already or it could be
> > exposed in the iommu group like the name attribute.  Otherwise we might
> > consider doing locking on first mapping.  Thanks,
> 
> GET_INFO is called in the beginning so QEMU will exit right there. No real 
> work will have been done till that moment so what is the problem?

GET_INFO uses container->tbl, which is set here, so how could it be
called first?  Thanks,

Alex

> >> +	mutex_unlock(&container->lock);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +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);
> >> +
> >> +	BUG_ON(!tbl);
> >> +	mutex_lock(&container->lock);
> >> +	if (tbl != container->tbl) {
> >> +		pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
> >> +				iommu_group_id(iommu_group),
> >> +				iommu_group_id(tbl->it_group));
> >> +	} else {
> >> +
> >> +		pr_debug("tce_vfio: detaching group #%u from iommu %p\n",
> >> +				iommu_group_id(iommu_group), iommu_group);
> >> +
> >> +		container->tbl = NULL;
> >> +		iommu_lock_table(tbl, false);
> >> +	}
> >> +	mutex_unlock(&container->lock);
> >> +}
> >> +
> >> +const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
> >> +	.name		= "iommu-vfio-powerpc",
> >> +	.owner		= THIS_MODULE,
> >> +	.open		= tce_iommu_open,
> >> +	.release	= tce_iommu_release,
> >> +	.ioctl		= tce_iommu_ioctl,
> >> +	.attach_group	= tce_iommu_attach_group,
> >> +	.detach_group	= tce_iommu_detach_group,
> >> +};
> >> +
> >> +static int __init tce_iommu_init(void)
> >> +{
> >> +	return vfio_register_iommu_driver(&tce_iommu_driver_ops);
> >> +}
> >> +
> >> +static void __exit tce_iommu_cleanup(void)
> >> +{
> >> +	vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
> >> +}
> >> +
> >> +module_init(tce_iommu_init);
> >> +module_exit(tce_iommu_cleanup);
> >> +
> >> +MODULE_VERSION(DRIVER_VERSION);
> >> +MODULE_LICENSE("GPL v2");
> >> +MODULE_AUTHOR(DRIVER_AUTHOR);
> >> +MODULE_DESCRIPTION(DRIVER_DESC);
> >> +
> >> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> >> index 4758d1b..ea9a9a7 100644
> >> --- a/include/uapi/linux/vfio.h
> >> +++ b/include/uapi/linux/vfio.h
> >> @@ -22,6 +22,7 @@
> >>   /* Extensions */
> >>
> >>   #define VFIO_TYPE1_IOMMU		1
> >> +#define VFIO_SPAPR_TCE_IOMMU		2
> >>
> >>   /*
> >>    * The IOCTL interface is designed for extensibility by embedding the
> >> @@ -365,4 +366,34 @@ struct vfio_iommu_type1_dma_unmap {
> >>
> >>   #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
> >>
> >> +/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
> >> +
> >> +/*
> >> + * The SPAPR TCE info struct provides the information about the PCI bus
> >> + * address ranges available for DMA, these values are programmed into
> >> + * the hardware so the guest has to know that information.
> >> + *
> >> + * The DMA 32 bit window start is an absolute PCI bus address.
> >> + * The IOVA address passed via map/unmap ioctls are absolute PCI bus
> >> + * addresses too so the window works as a filter rather than an offset
> >> + * for IOVA addresses.
> >> + *
> >> + * A flag will need to be added if other page sizes are supported,
> >> + * so as defined here, it is always 4k.
> >> + */
> >> +struct vfio_iommu_spapr_tce_info {
> >> +	__u32 argsz;
> >> +	__u32 flags;			/* reserved for future use */
> >> +	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
> >> +	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
> >> +};
> >> +
> >> +#define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
> >> +
> >> +/* Reuse type1 map/unmap structs as they are the same at the moment */
> >> +typedef struct vfio_iommu_type1_dma_map vfio_iommu_spapr_tce_dma_map;
> >> +typedef struct vfio_iommu_type1_dma_unmap vfio_iommu_spapr_tce_dma_unmap;
> >> +
> >> +/* ***************************************************************** */
> >> +
> >>   #endif /* _UAPIVFIO_H */
> >
> >
> >
> 
> 

Re: [PATCH 1/2] vfio powerpc: enabled on powernv platform

[Paul Mackerras]

On Mon, Feb 11, 2013 at 03:16:43PM -0700, Alex Williamson wrote:
> 
> Why do these all return long (vs int)?  Is this a POWER-ism?

On ppc64 the compiler tends to generate slightly shorter code with
longs than with ints.  The reason is that with ints the compiler has
to put in "extend sign word" instructions to convert 64-bit values
from arithmetic instructions to values in the 32-bit range.

Paul.