Merge tag 'vfio-v3.18-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:
 - Nested IOMMU extension to type1 (Will Deacon)
 - Restore MSIx message before enabling (Gavin Shan)
 - Fix remove path locking (Alex Williamson)

* tag 'vfio-v3.18-rc1' of git://github.com/awilliam/linux-vfio:
  vfio-pci: Fix remove path locking
  drivers/vfio: Export vfio_spapr_iommu_eeh_ioctl() with GPL
  vfio/pci: Restore MSIx message prior to enabling
  PCI: Export MSI message relevant functions
  vfio/iommu_type1: add new VFIO_TYPE1_NESTING_IOMMU IOMMU type
  iommu: introduce domain attribute for nesting IOMMUs

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 2f7c92c..9fab30a 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -302,6 +302,7 @@ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
 
        __get_cached_msi_msg(entry, msg);
 }
+EXPORT_SYMBOL_GPL(get_cached_msi_msg);
 
 void __write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
@@ -346,6 +347,7 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg)
 
        __write_msi_msg(entry, msg);
 }
+EXPORT_SYMBOL_GPL(write_msi_msg);
 
 static void free_msi_irqs(struct pci_dev *dev)
 {

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index f782533..9558da3 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -876,15 +876,11 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 {
        struct vfio_pci_device *vdev;
 
-       mutex_lock(&driver_lock);
-
        vdev = vfio_del_group_dev(&pdev->dev);
        if (vdev) {
                iommu_group_put(pdev->dev.iommu_group);
                kfree(vdev);
        }
-
-       mutex_unlock(&driver_lock);
 }
 
 static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
@@ -927,108 +923,90 @@ static struct pci_driver vfio_pci_driver = {
        .err_handler    = &vfio_err_handlers,
 };
 
-/*
- * Test whether a reset is necessary and possible.  We mark devices as
- * needs_reset when they are released, but don't have a function-local reset
- * available.  If any of these exist in the affected devices, we want to do
- * a bus/slot reset.  We also need all of the affected devices to be unused,
- * so we abort if any device has a non-zero refcnt.  driver_lock prevents a
- * device from being opened during the scan or unbound from vfio-pci.
- */
-static int vfio_pci_test_bus_reset(struct pci_dev *pdev, void *data)
-{
-       bool *needs_reset = data;
-       struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
-       int ret = -EBUSY;
-
-       if (pci_drv == &vfio_pci_driver) {
-               struct vfio_device *device;
-               struct vfio_pci_device *vdev;
-
-               device = vfio_device_get_from_dev(&pdev->dev);
-               if (!device)
-                       return ret;
-
-               vdev = vfio_device_data(device);
-               if (vdev) {
-                       if (vdev->needs_reset)
-                               *needs_reset = true;
-
-                       if (!vdev->refcnt)
-                               ret = 0;
-               }
-
-               vfio_device_put(device);
-       }
-
-       /*
-        * TODO: vfio-core considers groups to be viable even if some devices
-        * are attached to known drivers, like pci-stub or pcieport.  We can't
-        * freeze devices from being unbound to those drivers like we can
-        * here though, so it would be racy to test for them.  We also can't
-        * use device_lock() to prevent changes as that would interfere with
-        * PCI-core taking device_lock during bus reset.  For now, we require
-        * devices to be bound to vfio-pci to get a bus/slot reset on release.
-        */
-
-       return ret;
-}
+struct vfio_devices {
+       struct vfio_device **devices;
+       int cur_index;
+       int max_index;
+};
 
-/* Clear needs_reset on all affected devices after successful bus/slot reset */
-static int vfio_pci_clear_needs_reset(struct pci_dev *pdev, void *data)
+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) {
-               struct vfio_device *device;
-               struct vfio_pci_device *vdev;
+       if (pci_drv != &vfio_pci_driver)
+               return -EBUSY;
 
-               device = vfio_device_get_from_dev(&pdev->dev);
-               if (!device)
-                       return 0;
+       if (devs->cur_index == devs->max_index)
+               return -ENOSPC;
 
-               vdev = vfio_device_data(device);
-               if (vdev)
-                       vdev->needs_reset = false;
-
-               vfio_device_put(device);
-       }
+       devs->devices[devs->cur_index] = vfio_device_get_from_dev(&pdev->dev);
+       if (!devs->devices[devs->cur_index])
+               return -EINVAL;
 
+       devs->cur_index++;
        return 0;
 }
 
 /*
  * Attempt to do a bus/slot reset if there are devices affected by a reset for
  * this device that are needs_reset and all of the affected devices are unused
- * (!refcnt).  Callers of this function are required to hold driver_lock such
- * that devices can not be unbound from vfio-pci or opened by a user while we
- * test for and perform a bus/slot reset.
+ * (!refcnt).  Callers are required to hold driver_lock when calling this to
+ * prevent device opens and concurrent bus reset attempts.  We prevent device
+ * unbinds by acquiring and holding a reference to the vfio_device.
+ *
+ * NB: vfio-core considers a group to be viable even if some devices are
+ * bound to drivers like pci-stub or pcieport.  Here we require all devices
+ * to be bound to vfio_pci since that's the only way we can be sure they
+ * stay put.
  */
 static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 {
+       struct vfio_devices devs = { .cur_index = 0 };
+       int i = 0, ret = -EINVAL;
        bool needs_reset = false, slot = false;
-       int ret;
+       struct vfio_pci_device *tmp;
 
        if (!pci_probe_reset_slot(vdev->pdev->slot))
                slot = true;
        else if (pci_probe_reset_bus(vdev->pdev->bus))
                return;
 
-       if (vfio_pci_for_each_slot_or_bus(vdev->pdev,
-                                         vfio_pci_test_bus_reset,
-                                         &needs_reset, slot) || !needs_reset)
+       if (vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_count_devs,
+                                         &i, slot) || !i)
                return;
 
-       if (slot)
-               ret = pci_try_reset_slot(vdev->pdev->slot);
-       else
-               ret = pci_try_reset_bus(vdev->pdev->bus);
-
-       if (ret)
+       devs.max_index = i;
+       devs.devices = kcalloc(i, sizeof(struct vfio_device *), GFP_KERNEL);
+       if (!devs.devices)
                return;
 
-       vfio_pci_for_each_slot_or_bus(vdev->pdev,
-                                     vfio_pci_clear_needs_reset, NULL, slot);
+       if (vfio_pci_for_each_slot_or_bus(vdev->pdev,
+                                         vfio_pci_get_devs, &devs, slot))
+               goto put_devs;
+
+       for (i = 0; i < devs.cur_index; i++) {
+               tmp = vfio_device_data(devs.devices[i]);
+               if (tmp->needs_reset)
+                       needs_reset = true;
+               if (tmp->refcnt)
+                       goto put_devs;
+       }
+
+       if (needs_reset)
+               ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :
+                            pci_try_reset_bus(vdev->pdev->bus);
+
+put_devs:
+       for (i = 0; i < devs.cur_index; i++) {
+               if (!ret) {
+                       tmp = vfio_device_data(devs.devices[i]);
+                       tmp->needs_reset = false;
+               }
+               vfio_device_put(devs.devices[i]);
+       }
+
+       kfree(devs.devices);
 }
 
 static void __exit vfio_pci_cleanup(void)

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 9dd49c9..553212f 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -16,6 +16,7 @@
 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/eventfd.h>
+#include <linux/msi.h>
 #include <linux/pci.h>
 #include <linux/file.h>
 #include <linux/poll.h>
@@ -548,6 +549,20 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
                return PTR_ERR(trigger);
        }
 
+       /*
+        * The MSIx vector table resides in device memory which may be cleared
+        * via backdoor resets. We don't allow direct access to the vector
+        * table so even if a userspace driver attempts to save/restore around
+        * such a reset it would be unsuccessful. To avoid this, restore the
+        * cached value of the message prior to enabling.
+        */
+       if (msix) {
+               struct msi_msg msg;
+
+               get_cached_msi_msg(irq, &msg);
+               write_msi_msg(irq, &msg);
+       }
+
        ret = request_irq(irq, vfio_msihandler, 0,
                          vdev->ctx[vector].name, trigger);
        if (ret) {

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 0734fbe..583ccdb 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -57,7 +57,8 @@ struct vfio_iommu {
        struct list_head        domain_list;
        struct mutex            lock;
        struct rb_root          dma_list;
-       bool v2;
+       bool                    v2;
+       bool                    nesting;
 };
 
 struct vfio_domain {
@@ -705,6 +706,15 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
                goto out_free;
        }
 
+       if (iommu->nesting) {
+               int attr = 1;
+
+               ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
+                                           &attr);
+               if (ret)
+                       goto out_domain;
+       }
+
        ret = iommu_attach_group(domain->domain, iommu_group);
        if (ret)
                goto out_domain;
@@ -819,17 +829,26 @@ static void *vfio_iommu_type1_open(unsigned long arg)
 {
        struct vfio_iommu *iommu;
 
-       if (arg != VFIO_TYPE1_IOMMU && arg != VFIO_TYPE1v2_IOMMU)
-               return ERR_PTR(-EINVAL);
-
        iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
        if (!iommu)
                return ERR_PTR(-ENOMEM);
 
+       switch (arg) {
+       case VFIO_TYPE1_IOMMU:
+               break;
+       case VFIO_TYPE1_NESTING_IOMMU:
+               iommu->nesting = true;
+       case VFIO_TYPE1v2_IOMMU:
+               iommu->v2 = true;
+               break;
+       default:
+               kfree(iommu);
+               return ERR_PTR(-EINVAL);
+       }
+
        INIT_LIST_HEAD(&iommu->domain_list);
        iommu->dma_list = RB_ROOT;
        mutex_init(&iommu->lock);
-       iommu->v2 = (arg == VFIO_TYPE1v2_IOMMU);
 
        return iommu;
 }
@@ -885,6 +904,7 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
                switch (arg) {
                case VFIO_TYPE1_IOMMU:
                case VFIO_TYPE1v2_IOMMU:
+               case VFIO_TYPE1_NESTING_IOMMU:
                        return 1;
                case VFIO_DMA_CC_IOMMU:
                        if (!iommu)

diff --git a/drivers/vfio/vfio_spapr_eeh.c b/drivers/vfio/vfio_spapr_eeh.c
index 86dfceb..5fa42db 100644 (file)
--- a/drivers/vfio/vfio_spapr_eeh.c
+++ b/drivers/vfio/vfio_spapr_eeh.c
@@ -92,7 +92,7 @@ long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
 
        return ret;
 }
-EXPORT_SYMBOL(vfio_spapr_iommu_eeh_ioctl);
+EXPORT_SYMBOL_GPL(vfio_spapr_iommu_eeh_ioctl);
 
 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 20f9a52..7b02bcc 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -80,6 +80,7 @@ enum iommu_attr {
        DOMAIN_ATTR_FSL_PAMU_STASH,
        DOMAIN_ATTR_FSL_PAMU_ENABLE,
        DOMAIN_ATTR_FSL_PAMUV1,
+       DOMAIN_ATTR_NESTING,    /* two stages of translation */
        DOMAIN_ATTR_MAX,
 };
 

diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 6612974..29715d2 100644 (file)
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -33,6 +33,9 @@
 /* Check if EEH is supported */
 #define VFIO_EEH                       5
 
+/* Two-stage IOMMU */
+#define VFIO_TYPE1_NESTING_IOMMU       6       /* Implies v2 */
+
 /*
  * The IOCTL interface is designed for extensibility by embedding the
  * structure length (argsz) and flags into structures passed between