Merge tag 'vfio-v4.2-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - fix race with device reference versus driver release (Alex Williamson)

 - add reset hooks and Calxeda xgmac reset for vfio-platform (Eric Auger)

 - enable vfio-platform for ARM64 (Eric Auger)

 - tag Baptiste Reynal as vfio-platform sub-maintainer (Alex Williamson)

* tag 'vfio-v4.2-rc1' of git://github.com/awilliam/linux-vfio:
  MAINTAINERS: Add vfio-platform sub-maintainer
  VFIO: platform: enable ARM64 build
  VFIO: platform: Calxeda xgmac reset module
  VFIO: platform: populate the reset function on probe
  VFIO: platform: add reset callback
  VFIO: platform: add reset struct and lookup table
  vfio/pci: Fix racy vfio_device_get_from_dev() call

MAINTAINERS

@@ -10786,6 +10786,12 @@ F:	drivers/vfio/
 F:	include/linux/vfio.h
 F:	include/uapi/linux/vfio.h
 
+VFIO PLATFORM DRIVER
+M:	Baptiste Reynal <b.reynal@virtualopensystems.com>
+L:	kvm@vger.kernel.org
+S:	Maintained
+F:	drivers/vfio/platform/
+
 VIDEOBUF2 FRAMEWORK
 M:	Pawel Osciak <pawel@osciak.com>
 M:	Marek Szyprowski <m.szyprowski@samsung.com>

drivers/vfio/pci/vfio_pci.c

@@ -1056,19 +1056,21 @@ struct vfio_devices {
 static int vfio_pci_get_devs(struct pci_dev *pdev, void *data)
 {
 	struct vfio_devices *devs = data;
-	struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
-
-	if (pci_drv != &vfio_pci_driver)
-		return -EBUSY;
+	struct vfio_device *device;
 
 	if (devs->cur_index == devs->max_index)
 		return -ENOSPC;
 
-	devs->devices[devs->cur_index] = vfio_device_get_from_dev(&pdev->dev);
-	if (!devs->devices[devs->cur_index])
+	device = vfio_device_get_from_dev(&pdev->dev);
+	if (!device)
 		return -EINVAL;
 
-	devs->cur_index++;
+	if (pci_dev_driver(pdev) != &vfio_pci_driver) {
+		vfio_device_put(device);
+		return -EBUSY;
+	}
+
+	devs->devices[devs->cur_index++] = device;
 	return 0;
 }
 

drivers/vfio/platform/Kconfig

 config VFIO_PLATFORM
 	tristate "VFIO support for platform devices"
-	depends on VFIO && EVENTFD && ARM
+	depends on VFIO && EVENTFD && (ARM || ARM64)
 	select VFIO_VIRQFD
 	help
 	  Support for platform devices with VFIO. This is required to make
@@ -18,3 +18,5 @@ config VFIO_AMBA
 	  framework.
 
 	  If you don't know what to do here, say N.
+
+source "drivers/vfio/platform/reset/Kconfig"

drivers/vfio/platform/Makefile

@@ -2,7 +2,9 @@
 vfio-platform-y := vfio_platform.o vfio_platform_common.o vfio_platform_irq.o
 
 obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
+obj-$(CONFIG_VFIO_PLATFORM) += reset/
 
 vfio-amba-y := vfio_amba.o
 
 obj-$(CONFIG_VFIO_AMBA) += vfio-amba.o
+obj-$(CONFIG_VFIO_AMBA) += reset/

drivers/vfio/platform/reset/Kconfig

+config VFIO_PLATFORM_CALXEDAXGMAC_RESET
+	tristate "VFIO support for calxeda xgmac reset"
+	depends on VFIO_PLATFORM
+	help
+	  Enables the VFIO platform driver to handle reset for Calxeda xgmac
+
+	  If you don't know what to do here, say N.

drivers/vfio/platform/reset/Makefile

+vfio-platform-calxedaxgmac-y := vfio_platform_calxedaxgmac.o
+
+ccflags-y += -Idrivers/vfio/platform
+
+obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o

drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c

+/*
+ * VFIO platform driver specialized for Calxeda xgmac reset
+ * reset code is inherited from calxeda xgmac native driver
+ *
+ * Copyright 2010-2011 Calxeda, Inc.
+ * Copyright (c) 2015 Linaro Ltd.
+ *              www.linaro.org
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+
+#include "vfio_platform_private.h"
+
+#define DRIVER_VERSION  "0.1"
+#define DRIVER_AUTHOR   "Eric Auger <eric.auger@linaro.org>"
+#define DRIVER_DESC     "Reset support for Calxeda xgmac vfio platform device"
+
+#define CALXEDAXGMAC_COMPAT "calxeda,hb-xgmac"
+
+/* XGMAC Register definitions */
+#define XGMAC_CONTROL           0x00000000      /* MAC Configuration */
+
+/* DMA Control and Status Registers */
+#define XGMAC_DMA_CONTROL       0x00000f18      /* Ctrl (Operational Mode) */
+#define XGMAC_DMA_INTR_ENA      0x00000f1c      /* Interrupt Enable */
+
+/* DMA Control registe defines */
+#define DMA_CONTROL_ST          0x00002000      /* Start/Stop Transmission */
+#define DMA_CONTROL_SR          0x00000002      /* Start/Stop Receive */
+
+/* Common MAC defines */
+#define MAC_ENABLE_TX           0x00000008      /* Transmitter Enable */
+#define MAC_ENABLE_RX           0x00000004      /* Receiver Enable */
+
+static inline void xgmac_mac_disable(void __iomem *ioaddr)
+{
+	u32 value = readl(ioaddr + XGMAC_DMA_CONTROL);
+
+	value &= ~(DMA_CONTROL_ST | DMA_CONTROL_SR);
+	writel(value, ioaddr + XGMAC_DMA_CONTROL);
+
+	value = readl(ioaddr + XGMAC_CONTROL);
+	value &= ~(MAC_ENABLE_TX | MAC_ENABLE_RX);
+	writel(value, ioaddr + XGMAC_CONTROL);
+}
+
+int vfio_platform_calxedaxgmac_reset(struct vfio_platform_device *vdev)
+{
+	struct vfio_platform_region reg = vdev->regions[0];
+
+	if (!reg.ioaddr) {
+		reg.ioaddr =
+			ioremap_nocache(reg.addr, reg.size);
+		if (!reg.ioaddr)
+			return -ENOMEM;
+	}
+
+	/* disable IRQ */
+	writel(0, reg.ioaddr + XGMAC_DMA_INTR_ENA);
+
+	/* Disable the MAC core */
+	xgmac_mac_disable(reg.ioaddr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vfio_platform_calxedaxgmac_reset);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);

drivers/vfio/platform/vfio_platform_common.c

@@ -25,6 +25,44 @@
 
 static DEFINE_MUTEX(driver_lock);
 
+static const struct vfio_platform_reset_combo reset_lookup_table[] = {
+	{
+		.compat = "calxeda,hb-xgmac",
+		.reset_function_name = "vfio_platform_calxedaxgmac_reset",
+		.module_name = "vfio-platform-calxedaxgmac",
+	},
+};
+
+static void vfio_platform_get_reset(struct vfio_platform_device *vdev,
+				    struct device *dev)
+{
+	const char *compat;
+	int (*reset)(struct vfio_platform_device *);
+	int ret, i;
+
+	ret = device_property_read_string(dev, "compatible", &compat);
+	if (ret)
+		return;
+
+	for (i = 0 ; i < ARRAY_SIZE(reset_lookup_table); i++) {
+		if (!strcmp(reset_lookup_table[i].compat, compat)) {
+			request_module(reset_lookup_table[i].module_name);
+			reset = __symbol_get(
+				reset_lookup_table[i].reset_function_name);
+			if (reset) {
+				vdev->reset = reset;
+				return;
+			}
+		}
+	}
+}
+
+static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
+{
+	if (vdev->reset)
+		symbol_put_addr(vdev->reset);
+}
+
 static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
 {
 	int cnt = 0, i;
@@ -100,6 +138,8 @@ static void vfio_platform_release(void *device_data)
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
+		if (vdev->reset)
+			vdev->reset(vdev);
 		vfio_platform_regions_cleanup(vdev);
 		vfio_platform_irq_cleanup(vdev);
 	}
@@ -127,6 +167,9 @@ static int vfio_platform_open(void *device_data)
 		ret = vfio_platform_irq_init(vdev);
 		if (ret)
 			goto err_irq;
+
+		if (vdev->reset)
+			vdev->reset(vdev);
 	}
 
 	vdev->refcnt++;
@@ -159,6 +202,8 @@ static long vfio_platform_ioctl(void *device_data,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
+		if (vdev->reset)
+			vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
 		info.flags = vdev->flags;
 		info.num_regions = vdev->num_regions;
 		info.num_irqs = vdev->num_irqs;
@@ -252,8 +297,12 @@ static long vfio_platform_ioctl(void *device_data,
 
 		return ret;
 
-	} else if (cmd == VFIO_DEVICE_RESET)
+	} else if (cmd == VFIO_DEVICE_RESET) {
+		if (vdev->reset)
+			return vdev->reset(vdev);
+		else
 			return -EINVAL;
+	}
 
 	return -ENOTTY;
 }
@@ -502,6 +551,8 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 		return ret;
 	}
 
+	vfio_platform_get_reset(vdev, dev);
+
 	mutex_init(&vdev->igate);
 
 	return 0;
@@ -513,8 +564,11 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
 	struct vfio_platform_device *vdev;
 
 	vdev = vfio_del_group_dev(dev);
-	if (vdev)
+
+	if (vdev) {
+		vfio_platform_put_reset(vdev);
 		iommu_group_put(dev->iommu_group);
+	}
 
 	return vdev;
 }

drivers/vfio/platform/vfio_platform_private.h

@@ -67,6 +67,13 @@ struct vfio_platform_device {
 	struct resource*
 		(*get_resource)(struct vfio_platform_device *vdev, int i);
 	int	(*get_irq)(struct vfio_platform_device *vdev, int i);
+	int	(*reset)(struct vfio_platform_device *vdev);
+};
+
+struct vfio_platform_reset_combo {
+	const char *compat;
+	const char *reset_function_name;
+	const char *module_name;
 };
 
 extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,

drivers/vfio/vfio.c

@@ -661,18 +661,29 @@ int vfio_add_group_dev(struct device *dev,
 EXPORT_SYMBOL_GPL(vfio_add_group_dev);
 
 /**
- * Get a reference to the vfio_device for a device that is known to
- * be bound to a vfio driver.  The driver implicitly holds a
- * vfio_device reference between vfio_add_group_dev and
- * vfio_del_group_dev.  We can therefore use drvdata to increment
- * that reference from the struct device.  This additional
- * reference must be released by calling vfio_device_put.
+ * Get a reference to the vfio_device for a device.  Even if the
+ * caller thinks they own the device, they could be racing with a
+ * release call path, so we can't trust drvdata for the shortcut.
+ * Go the long way around, from the iommu_group to the vfio_group
+ * to the vfio_device.
  */
 struct vfio_device *vfio_device_get_from_dev(struct device *dev)
 {
-	struct vfio_device *device = dev_get_drvdata(dev);
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+	struct vfio_device *device;
 
-	vfio_device_get(device);
+	iommu_group = iommu_group_get(dev);
+	if (!iommu_group)
+		return NULL;
+
+	group = vfio_group_get_from_iommu(iommu_group);
+	iommu_group_put(iommu_group);
+	if (!group)
+		return NULL;
+
+	device = vfio_group_get_device(group, dev);
+	vfio_group_put(group);
 
 	return device;
 }