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VFIO updates for v3.20-rc1

Browse source 
- IOMMU updates based on trace analysis (Alex Williamson)
  - VFIO device request interface (Alex Williamson)
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Merge tag 'vfio-v3.20-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - IOMMU updates based on trace analysis
 - VFIO device request interface

* tag 'vfio-v3.20-rc1' of git://github.com/awilliam/linux-vfio:
  vfio-pci: Add device request interface
  vfio-pci: Generalize setup of simple eventfds
  vfio: Add and use device request op for vfio bus drivers
  vfio: Tie IOMMU group reference to vfio group
  vfio: Add device tracking during unbind
  vfio/type1: Add conditional rescheduling
  vfio/type1: Chunk contiguous reserved/invalid page mappings
  vfio/type1: DMA unmap chunking
This commit is contained in:
Linus Torvalds 2015-02-21 11:55:21 -08:00
commit c189cb8ef6
7 changed files with 242 additions and 42 deletions
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21
drivers/vfio/pci/vfio_pci.c
View file

@ -239,9 +239,12 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
}
} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX)
} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
if (pci_is_pcie(vdev->pdev))
return 1;
} else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
return 1;
}
return 0;
}
@ -464,6 +467,7 @@ static long vfio_pci_ioctl(void *device_data,
switch (info.index) {
case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
case VFIO_PCI_REQ_IRQ_INDEX:
break;
case VFIO_PCI_ERR_IRQ_INDEX:
if (pci_is_pcie(vdev->pdev))
@ -828,6 +832,20 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
req_len, vma->vm_page_prot);
}
static void vfio_pci_request(void *device_data, unsigned int count)
{
struct vfio_pci_device *vdev = device_data;
mutex_lock(&vdev->igate);
if (vdev->req_trigger) {
dev_dbg(&vdev->pdev->dev, "Requesting device from user\n");
eventfd_signal(vdev->req_trigger, 1);
}
mutex_unlock(&vdev->igate);
}
static const struct vfio_device_ops vfio_pci_ops = {
.name = "vfio-pci",
.open = vfio_pci_open,
@ -836,6 +854,7 @@ static const struct vfio_device_ops vfio_pci_ops = {
.read = vfio_pci_read,
.write = vfio_pci_write,
.mmap = vfio_pci_mmap,
.request = vfio_pci_request,
};
static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

60
drivers/vfio/pci/vfio_pci_intrs.c
View file

@ -763,46 +763,70 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev,
return 0;
}
static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags, void *data)
static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
uint32_t flags, void *data)
{
int32_t fd = *(int32_t *)data;
if ((index != VFIO_PCI_ERR_IRQ_INDEX) ||
!(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
if (!(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
return -EINVAL;
/* DATA_NONE/DATA_BOOL enables loopback testing */
if (flags & VFIO_IRQ_SET_DATA_NONE) {
if (vdev->err_trigger)
eventfd_signal(vdev->err_trigger, 1);
if (*ctx)
eventfd_signal(*ctx, 1);
return 0;
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
uint8_t trigger = *(uint8_t *)data;
if (trigger && vdev->err_trigger)
eventfd_signal(vdev->err_trigger, 1);
if (trigger && *ctx)
eventfd_signal(*ctx, 1);
return 0;
}
/* Handle SET_DATA_EVENTFD */
if (fd == -1) {
if (vdev->err_trigger)
eventfd_ctx_put(vdev->err_trigger);
vdev->err_trigger = NULL;
if (*ctx)
eventfd_ctx_put(*ctx);
*ctx = NULL;
return 0;
} else if (fd >= 0) {
struct eventfd_ctx *efdctx;
efdctx = eventfd_ctx_fdget(fd);
if (IS_ERR(efdctx))
return PTR_ERR(efdctx);
if (vdev->err_trigger)
eventfd_ctx_put(vdev->err_trigger);
vdev->err_trigger = efdctx;
if (*ctx)
eventfd_ctx_put(*ctx);
*ctx = efdctx;
return 0;
} else
return -EINVAL;
}
static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags, void *data)
{
if (index != VFIO_PCI_ERR_IRQ_INDEX)
return -EINVAL;
/*
* We should sanitize start & count, but that wasn't caught
* originally, so this IRQ index must forever ignore them :-(
*/
return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger, flags, data);
}
static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags, void *data)
{
if (index != VFIO_PCI_REQ_IRQ_INDEX || start != 0 || count != 1)
return -EINVAL;
return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger, flags, data);
}
int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
unsigned index, unsigned start, unsigned count,
void *data)
@ -844,6 +868,12 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
func = vfio_pci_set_err_trigger;
break;
}
case VFIO_PCI_REQ_IRQ_INDEX:
switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
case VFIO_IRQ_SET_ACTION_TRIGGER:
func = vfio_pci_set_req_trigger;
break;
}
}
if (!func)

1
drivers/vfio/pci/vfio_pci_private.h
View file

@ -58,6 +58,7 @@ struct vfio_pci_device {
struct pci_saved_state *pci_saved_state;
int refcnt;
struct eventfd_ctx *err_trigger;
struct eventfd_ctx *req_trigger;
};
#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)

119
drivers/vfio/vfio.c
View file

@ -63,6 +63,11 @@ struct vfio_container {
void *iommu_data;
};
struct vfio_unbound_dev {
struct device *dev;
struct list_head unbound_next;
};
struct vfio_group {
struct kref kref;
int minor;
@ -75,6 +80,8 @@ struct vfio_group {
struct notifier_block nb;
struct list_head vfio_next;
struct list_head container_next;
struct list_head unbound_list;
struct mutex unbound_lock;
atomic_t opened;
};
@ -204,6 +211,8 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
kref_init(&group->kref);
INIT_LIST_HEAD(&group->device_list);
mutex_init(&group->device_lock);
INIT_LIST_HEAD(&group->unbound_list);
mutex_init(&group->unbound_lock);
atomic_set(&group->container_users, 0);
atomic_set(&group->opened, 0);
group->iommu_group = iommu_group;
@ -264,13 +273,22 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
static void vfio_group_release(struct kref *kref)
{
struct vfio_group *group = container_of(kref, struct vfio_group, kref);
struct vfio_unbound_dev *unbound, *tmp;
struct iommu_group *iommu_group = group->iommu_group;
WARN_ON(!list_empty(&group->device_list));
list_for_each_entry_safe(unbound, tmp,
&group->unbound_list, unbound_next) {
list_del(&unbound->unbound_next);
kfree(unbound);
}
device_destroy(vfio.class, MKDEV(MAJOR(vfio.group_devt), group->minor));
list_del(&group->vfio_next);
vfio_free_group_minor(group->minor);
vfio_group_unlock_and_free(group);
iommu_group_put(iommu_group);
}
static void vfio_group_put(struct vfio_group *group)
@ -440,17 +458,36 @@ static bool vfio_whitelisted_driver(struct device_driver *drv)
}
/*
* A vfio group is viable for use by userspace if all devices are either
* driver-less or bound to a vfio or whitelisted driver. We test the
* latter by the existence of a struct vfio_device matching the dev.
* A vfio group is viable for use by userspace if all devices are in
* one of the following states:
* - driver-less
* - bound to a vfio driver
* - bound to a whitelisted driver
*
* We use two methods to determine whether a device is bound to a vfio
* driver. The first is to test whether the device exists in the vfio
* group. The second is to test if the device exists on the group
* unbound_list, indicating it's in the middle of transitioning from
* a vfio driver to driver-less.
*/
static int vfio_dev_viable(struct device *dev, void *data)
{
struct vfio_group *group = data;
struct vfio_device *device;
struct device_driver *drv = ACCESS_ONCE(dev->driver);
struct vfio_unbound_dev *unbound;
int ret = -EINVAL;
if (!drv || vfio_whitelisted_driver(drv))
mutex_lock(&group->unbound_lock);
list_for_each_entry(unbound, &group->unbound_list, unbound_next) {
if (dev == unbound->dev) {
ret = 0;
break;
}
}
mutex_unlock(&group->unbound_lock);
if (!ret || !drv || vfio_whitelisted_driver(drv))
return 0;
device = vfio_group_get_device(group, dev);
@ -459,7 +496,7 @@ static int vfio_dev_viable(struct device *dev, void *data)
return 0;
}
return -EINVAL;
return ret;
}
/**
@ -501,6 +538,7 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb,
{
struct vfio_group *group = container_of(nb, struct vfio_group, nb);
struct device *dev = data;
struct vfio_unbound_dev *unbound;
/*
* Need to go through a group_lock lookup to get a reference or we
@ -550,6 +588,17 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb,
* stop the system to maintain isolation. At a minimum, we'd
* want a toggle to disable driver auto probe for this device.
*/
mutex_lock(&group->unbound_lock);
list_for_each_entry(unbound,
&group->unbound_list, unbound_next) {
if (dev == unbound->dev) {
list_del(&unbound->unbound_next);
kfree(unbound);
break;
}
}
mutex_unlock(&group->unbound_lock);
break;
}
@ -578,6 +627,12 @@ int vfio_add_group_dev(struct device *dev,
iommu_group_put(iommu_group);
return PTR_ERR(group);
}
} else {
/*
* A found vfio_group already holds a reference to the
* iommu_group. A created vfio_group keeps the reference.
*/
iommu_group_put(iommu_group);
}
device = vfio_group_get_device(group, dev);
@ -586,21 +641,19 @@ int vfio_add_group_dev(struct device *dev,
dev_name(dev), iommu_group_id(iommu_group));
vfio_device_put(device);
vfio_group_put(group);
iommu_group_put(iommu_group);
return -EBUSY;
}
device = vfio_group_create_device(group, dev, ops, device_data);
if (IS_ERR(device)) {
vfio_group_put(group);
iommu_group_put(iommu_group);
return PTR_ERR(device);
}
/*
* Added device holds reference to iommu_group and vfio_device
* (which in turn holds reference to vfio_group). Drop extra
* group reference used while acquiring device.
* Drop all but the vfio_device reference. The vfio_device holds
* a reference to the vfio_group, which holds a reference to the
* iommu_group.
*/
vfio_group_put(group);
@ -655,8 +708,9 @@ void *vfio_del_group_dev(struct device *dev)
{
struct vfio_device *device = dev_get_drvdata(dev);
struct vfio_group *group = device->group;
struct iommu_group *iommu_group = group->iommu_group;
void *device_data = device->device_data;
struct vfio_unbound_dev *unbound;
unsigned int i = 0;
/*
* The group exists so long as we have a device reference. Get
@ -664,15 +718,50 @@ void *vfio_del_group_dev(struct device *dev)
*/
vfio_group_get(group);
/*
* When the device is removed from the group, the group suddenly
* becomes non-viable; the device has a driver (until the unbind
* completes), but it's not present in the group. This is bad news
* for any external users that need to re-acquire a group reference
* in order to match and release their existing reference. To
* solve this, we track such devices on the unbound_list to bridge
* the gap until they're fully unbound.
*/
unbound = kzalloc(sizeof(*unbound), GFP_KERNEL);
if (unbound) {
unbound->dev = dev;
mutex_lock(&group->unbound_lock);
list_add(&unbound->unbound_next, &group->unbound_list);
mutex_unlock(&group->unbound_lock);
}
WARN_ON(!unbound);
vfio_device_put(device);
/* TODO send a signal to encourage this to be released */
wait_event(vfio.release_q, !vfio_dev_present(group, dev));
/*
* If the device is still present in the group after the above
* 'put', then it is in use and we need to request it from the
* bus driver. The driver may in turn need to request the
* device from the user. We send the request on an arbitrary
* interval with counter to allow the driver to take escalating
* measures to release the device if it has the ability to do so.
*/
do {
device = vfio_group_get_device(group, dev);
if (!device)
break;
if (device->ops->request)
device->ops->request(device_data, i++);
vfio_device_put(device);
} while (wait_event_interruptible_timeout(vfio.release_q,
!vfio_dev_present(group, dev),
HZ * 10) <= 0);
vfio_group_put(group);
iommu_group_put(iommu_group);
return device_data;
}
EXPORT_SYMBOL_GPL(vfio_del_group_dev);

76
drivers/vfio/vfio_iommu_type1.c
View file

@ -66,6 +66,7 @@ struct vfio_domain {
struct list_head next;
struct list_head group_list;
int prot; /* IOMMU_CACHE */
bool fgsp; /* Fine-grained super pages */
};
struct vfio_dma {
@ -264,6 +265,7 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
bool lock_cap = capable(CAP_IPC_LOCK);
long ret, i;
bool rsvd;
if (!current->mm)
return -ENODEV;
@ -272,10 +274,9 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
if (ret)
return ret;
if (is_invalid_reserved_pfn(*pfn_base))
return 1;
rsvd = is_invalid_reserved_pfn(*pfn_base);
if (!lock_cap && current->mm->locked_vm + 1 > limit) {
if (!rsvd && !lock_cap && current->mm->locked_vm + 1 > limit) {
put_pfn(*pfn_base, prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
limit << PAGE_SHIFT);
@ -283,6 +284,7 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
}
if (unlikely(disable_hugepages)) {
if (!rsvd)
vfio_lock_acct(1);
return 1;
}
@ -295,12 +297,14 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
if (ret)
break;
if (pfn != *pfn_base + i || is_invalid_reserved_pfn(pfn)) {
if (pfn != *pfn_base + i ||
rsvd != is_invalid_reserved_pfn(pfn)) {
put_pfn(pfn, prot);
break;
}
if (!lock_cap && current->mm->locked_vm + i + 1 > limit) {
if (!rsvd && !lock_cap &&
current->mm->locked_vm + i + 1 > limit) {
put_pfn(pfn, prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
__func__, limit << PAGE_SHIFT);
@ -308,6 +312,7 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
}
}
if (!rsvd)
vfio_lock_acct(i);
return i;
@ -346,12 +351,14 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
domain = d = list_first_entry(&iommu->domain_list,
struct vfio_domain, next);
list_for_each_entry_continue(d, &iommu->domain_list, next)
list_for_each_entry_continue(d, &iommu->domain_list, next) {
iommu_unmap(d->domain, dma->iova, dma->size);
cond_resched();
}
while (iova < end) {
size_t unmapped;
phys_addr_t phys;
size_t unmapped, len;
phys_addr_t phys, next;
phys = iommu_iova_to_phys(domain->domain, iova);
if (WARN_ON(!phys)) {
@ -359,7 +366,19 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
continue;
}
unmapped = iommu_unmap(domain->domain, iova, PAGE_SIZE);
/*
* To optimize for fewer iommu_unmap() calls, each of which
* may require hardware cache flushing, try to find the
* largest contiguous physical memory chunk to unmap.
*/
for (len = PAGE_SIZE;
!domain->fgsp && iova + len < end; len += PAGE_SIZE) {
next = iommu_iova_to_phys(domain->domain, iova + len);
if (next != phys + len)
break;
}
unmapped = iommu_unmap(domain->domain, iova, len);
if (WARN_ON(!unmapped))
break;
@ -367,6 +386,8 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
unmapped >> PAGE_SHIFT,
dma->prot, false);
iova += unmapped;
cond_resched();
}
vfio_lock_acct(-unlocked);
@ -511,6 +532,8 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
map_try_harder(d, iova, pfn, npage, prot))
goto unwind;
}
cond_resched();
}
return 0;
@ -665,6 +688,39 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
return 0;
}
/*
* We change our unmap behavior slightly depending on whether the IOMMU
* supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
* for practically any contiguous power-of-two mapping we give it. This means
* we don't need to look for contiguous chunks ourselves to make unmapping
* more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
* with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
* significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
* hugetlbfs is in use.
*/
static void vfio_test_domain_fgsp(struct vfio_domain *domain)
{
struct page *pages;
int ret, order = get_order(PAGE_SIZE * 2);
pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!pages)
return;
ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
IOMMU_READ | IOMMU_WRITE | domain->prot);
if (!ret) {
size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
if (unmapped == PAGE_SIZE)
iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
else
domain->fgsp = true;
}
__free_pages(pages, order);
}
static int vfio_iommu_type1_attach_group(void *iommu_data,
struct iommu_group *iommu_group)
{
@ -758,6 +814,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
}
}
vfio_test_domain_fgsp(domain);
/* replay mappings on new domains */
ret = vfio_iommu_replay(iommu, domain);
if (ret)

2
include/linux/vfio.h
View file

@ -26,6 +26,7 @@
* @ioctl: Perform ioctl(2) on device file descriptor, supporting VFIO_DEVICE_*
* operations documented below
* @mmap: Perform mmap(2) on a region of the device file descriptor
* @request: Request for the bus driver to release the device
*/
struct vfio_device_ops {
char *name;
@ -38,6 +39,7 @@ struct vfio_device_ops {
long (*ioctl)(void *device_data, unsigned int cmd,
unsigned long arg);
int (*mmap)(void *device_data, struct vm_area_struct *vma);
void (*request)(void *device_data, unsigned int count);
};
extern int vfio_add_group_dev(struct device *dev,

1
include/uapi/linux/vfio.h
View file

@ -333,6 +333,7 @@ enum {
VFIO_PCI_MSI_IRQ_INDEX,
VFIO_PCI_MSIX_IRQ_INDEX,
VFIO_PCI_ERR_IRQ_INDEX,
VFIO_PCI_REQ_IRQ_INDEX,
VFIO_PCI_NUM_IRQS
};