RE: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting AER
-Original Message-
From: Alex Williamson [mailto:alex.william...@redhat.com]
Sent: Wednesday, January 09, 2013 11:05 AM
To: Pandarathil, Vijaymohan R
Cc: Bjorn Helgaas; Gleb Natapov; kvm@vger.kernel.org; qemu-
de...@nongnu.org; linux-...@vger.kernel.org; linux-ker...@vger.kernel.org
Subject: Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting
AER
On Wed, 2013-01-09 at 10:52 -0700, Alex Williamson wrote:
On Wed, 2013-01-09 at 06:26 +, Pandarathil, Vijaymohan R wrote:
- New ioctl which is used to pass the eventfd that is signaled when
an error occurs in the vfio_pci_device
- Register pci_error_handler for the vfio_pci driver
- When the device encounters an error, the error handler registered
by
the vfio_pci driver gets invoked by the AER infrastructure
- In the error handler, signal the eventfd registered for the device.
- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.
Signed-off-by: Vijay Mohan Pandarathil vijaymohan.pandarat...@hp.com
---
drivers/vfio/pci/vfio_pci.c | 29 +
drivers/vfio/pci/vfio_pci_private.h | 1 +
drivers/vfio/vfio.c | 8
include/linux/vfio.h| 1 +
include/uapi/linux/vfio.h | 9 +
5 files changed, 48 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 6c11994..4ae9526 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data,
if (vdev-reset_works)
info.flags |= VFIO_DEVICE_FLAGS_RESET;
+ info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY;
+
This appears to be a PCI specific flag, so the name should include
_PCI_. We also support non-PCIe devices and it seems like it would be
possible to not have AER support available, so shouldn't this be
conditional?
Will do that.
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data,
return ret;
+ } else if (cmd == VFIO_DEVICE_SET_ERRFD) {
+ int32_t fd = (int32_t)arg;
+
+ if (fd 0)
+ return -EINVAL;
+
+ vdev-err_trigger = eventfd_ctx_fdget(fd);
+
+ if (IS_ERR(vdev-err_trigger))
+ return PTR_ERR(vdev-err_trigger);
+
+ return 0;
+
I'm not sure why we wouldn't describe this as just another interrupt
from the device and configure it via SET_IRQ. This ioctl has very
limited use and doesn't follow any of the conventions of all the other
vfio ioctls.
I thought this was a fairly simple ioctl to implement this way. Moreover,
there is no device interrupt involved. Let me know if you really want to
model it as a SET_IRQ ioctl.
} else if (cmd == VFIO_DEVICE_RESET)
return vdev-reset_works ?
pci_reset_function(vdev-pdev) : -EINVAL;
@@ -527,11 +542,25 @@ static void vfio_pci_remove(struct pci_dev *pdev)
kfree(vdev);
}
+static pci_ers_result_t vfio_err_detected(struct pci_dev *pdev,
+ pci_channel_state_t state)
+{
+ struct vfio_pci_device *vdev = vfio_get_vdev(pdev-dev);
+
+ eventfd_signal(vdev-err_trigger, 1);
+ return PCI_ERS_RESULT_CAN_RECOVER;
+}
What if err_trigger hasn't been set?
Will fix that.
+
+static const struct pci_error_handlers vfio_err_handlers = {
+ .error_detected = vfio_err_detected,
+};
+
static struct pci_driver vfio_pci_driver = {
.name = vfio-pci,
.id_table = NULL, /* only dynamic ids */
.probe = vfio_pci_probe,
.remove = vfio_pci_remove,
+ .err_handler= vfio_err_handlers,
};
static void __exit vfio_pci_cleanup(void)
diff --git a/drivers/vfio/pci/vfio_pci_private.h
b/drivers/vfio/pci/vfio_pci_private.h
index 611827c..daee62f 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -55,6 +55,7 @@ struct vfio_pci_device {
boolbardirty;
struct pci_saved_state *pci_saved_state;
atomic_trefcnt;
+ struct eventfd_ctx *err_trigger;
};
#define is_intx(vdev) (vdev-irq_type == VFIO_PCI_INTX_IRQ_INDEX)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 56097c6..5ed5a54 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -693,6 +693,14 @@ void *vfio_del_group_dev(struct device *dev)
}
EXPORT_SYMBOL_GPL(vfio_del_group_dev);
+void *vfio_get_vdev(struct device *dev)
+{
+ struct vfio_device *device = dev_get_drvdata(dev);
+
+ return
Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting AER
On Fri, 2013-01-11 at 08:45 +, Pandarathil, Vijaymohan R wrote:
-Original Message-
From: Alex Williamson [mailto:alex.william...@redhat.com]
Sent: Wednesday, January 09, 2013 11:05 AM
To: Pandarathil, Vijaymohan R
Cc: Bjorn Helgaas; Gleb Natapov; kvm@vger.kernel.org; qemu-
de...@nongnu.org; linux-...@vger.kernel.org; linux-ker...@vger.kernel.org
Subject: Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting
AER
On Wed, 2013-01-09 at 10:52 -0700, Alex Williamson wrote:
On Wed, 2013-01-09 at 06:26 +, Pandarathil, Vijaymohan R wrote:
- New ioctl which is used to pass the eventfd that is signaled
when
an error occurs in the vfio_pci_device
- Register pci_error_handler for the vfio_pci driver
- When the device encounters an error, the error handler
registered
by
the vfio_pci driver gets invoked by the AER infrastructure
- In the error handler, signal the eventfd registered for the
device.
- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.
Signed-off-by: Vijay Mohan Pandarathil vijaymohan.pandarat...@hp.com
---
drivers/vfio/pci/vfio_pci.c | 29 +
drivers/vfio/pci/vfio_pci_private.h | 1 +
drivers/vfio/vfio.c | 8
include/linux/vfio.h| 1 +
include/uapi/linux/vfio.h | 9 +
5 files changed, 48 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 6c11994..4ae9526 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data,
if (vdev-reset_works)
info.flags |= VFIO_DEVICE_FLAGS_RESET;
+ info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY;
+
This appears to be a PCI specific flag, so the name should include
_PCI_. We also support non-PCIe devices and it seems like it would be
possible to not have AER support available, so shouldn't this be
conditional?
Will do that.
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data,
return ret;
+ } else if (cmd == VFIO_DEVICE_SET_ERRFD) {
+ int32_t fd = (int32_t)arg;
+
+ if (fd 0)
+ return -EINVAL;
+
+ vdev-err_trigger = eventfd_ctx_fdget(fd);
+
+ if (IS_ERR(vdev-err_trigger))
+ return PTR_ERR(vdev-err_trigger);
+
+ return 0;
+
I'm not sure why we wouldn't describe this as just another interrupt
from the device and configure it via SET_IRQ. This ioctl has very
limited use and doesn't follow any of the conventions of all the other
vfio ioctls.
I thought this was a fairly simple ioctl to implement this way. Moreover,
there is no device interrupt involved. Let me know if you really want to
model it as a SET_IRQ ioctl.
I'd like to see something else for sure. We're trying to do AER
piecemeal but this ioctl leaves no room for anything else. Seems like a
soon to be wasted ioctl number. Note that there isn't even a de-assign
interface, nor a flag to set to indicate de-assignment. The SET_IRQ
ioctl already handles these in a very similar way to how we'd want to
handle it for error signaling. It doesn't seem like that much of a
stretch to me to include it there, but I'd also entertain other ideas.
Thanks,
Alex
} else if (cmd == VFIO_DEVICE_RESET)
return vdev-reset_works ?
pci_reset_function(vdev-pdev) : -EINVAL;
@@ -527,11 +542,25 @@ static void vfio_pci_remove(struct pci_dev *pdev)
kfree(vdev);
}
+static pci_ers_result_t vfio_err_detected(struct pci_dev *pdev,
+ pci_channel_state_t state)
+{
+ struct vfio_pci_device *vdev = vfio_get_vdev(pdev-dev);
+
+ eventfd_signal(vdev-err_trigger, 1);
+ return PCI_ERS_RESULT_CAN_RECOVER;
+}
What if err_trigger hasn't been set?
Will fix that.
+
+static const struct pci_error_handlers vfio_err_handlers = {
+ .error_detected = vfio_err_detected,
+};
+
static struct pci_driver vfio_pci_driver = {
.name = vfio-pci,
.id_table = NULL, /* only dynamic ids */
.probe = vfio_pci_probe,
.remove = vfio_pci_remove,
+ .err_handler= vfio_err_handlers,
};
static void __exit vfio_pci_cleanup(void
Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting AER
On Fri, Jan 11, 2013 at 08:46:35AM -0700, Alex Williamson wrote:
On Fri, 2013-01-11 at 08:45 +, Pandarathil, Vijaymohan R wrote:
-Original Message-
From: Alex Williamson [mailto:alex.william...@redhat.com]
Sent: Wednesday, January 09, 2013 11:05 AM
To: Pandarathil, Vijaymohan R
Cc: Bjorn Helgaas; Gleb Natapov; kvm@vger.kernel.org; qemu-
de...@nongnu.org; linux-...@vger.kernel.org; linux-ker...@vger.kernel.org
Subject: Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting
AER
On Wed, 2013-01-09 at 10:52 -0700, Alex Williamson wrote:
On Wed, 2013-01-09 at 06:26 +, Pandarathil, Vijaymohan R wrote:
- New ioctl which is used to pass the eventfd that is signaled
when
an error occurs in the vfio_pci_device
- Register pci_error_handler for the vfio_pci driver
- When the device encounters an error, the error handler
registered
by
the vfio_pci driver gets invoked by the AER infrastructure
- In the error handler, signal the eventfd registered for the
device.
- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.
Signed-off-by: Vijay Mohan Pandarathil vijaymohan.pandarat...@hp.com
---
drivers/vfio/pci/vfio_pci.c | 29
+
drivers/vfio/pci/vfio_pci_private.h | 1 +
drivers/vfio/vfio.c | 8
include/linux/vfio.h| 1 +
include/uapi/linux/vfio.h | 9 +
5 files changed, 48 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 6c11994..4ae9526 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data,
if (vdev-reset_works)
info.flags |= VFIO_DEVICE_FLAGS_RESET;
+ info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY;
+
This appears to be a PCI specific flag, so the name should include
_PCI_. We also support non-PCIe devices and it seems like it would be
possible to not have AER support available, so shouldn't this be
conditional?
Will do that.
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data,
return ret;
+ } else if (cmd == VFIO_DEVICE_SET_ERRFD) {
+ int32_t fd = (int32_t)arg;
+
+ if (fd 0)
+ return -EINVAL;
+
+ vdev-err_trigger = eventfd_ctx_fdget(fd);
+
+ if (IS_ERR(vdev-err_trigger))
+ return PTR_ERR(vdev-err_trigger);
+
+ return 0;
+
I'm not sure why we wouldn't describe this as just another interrupt
from the device and configure it via SET_IRQ. This ioctl has very
limited use and doesn't follow any of the conventions of all the other
vfio ioctls.
I thought this was a fairly simple ioctl to implement this way. Moreover,
there is no device interrupt involved. Let me know if you really want to
model it as a SET_IRQ ioctl.
I'd like to see something else for sure. We're trying to do AER
piecemeal but this ioctl leaves no room for anything else. Seems like a
soon to be wasted ioctl number. Note that there isn't even a de-assign
interface, nor a flag to set to indicate de-assignment. The SET_IRQ
ioctl already handles these in a very similar way to how we'd want to
handle it for error signaling. It doesn't seem like that much of a
stretch to me to include it there, but I'd also entertain other ideas.
Thanks,
Alex
Yes it would be good to have a picture of the dependencies necessary to
implement passthrough, before introducing an incompatible interface.
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Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting AER
On Wed, 2013-01-09 at 06:26 +, Pandarathil, Vijaymohan R wrote:
- New ioctl which is used to pass the eventfd that is signaled when
an error occurs in the vfio_pci_device
- Register pci_error_handler for the vfio_pci driver
- When the device encounters an error, the error handler registered by
the vfio_pci driver gets invoked by the AER infrastructure
- In the error handler, signal the eventfd registered for the device.
- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.
Signed-off-by: Vijay Mohan Pandarathil vijaymohan.pandarat...@hp.com
---
drivers/vfio/pci/vfio_pci.c | 29 +
drivers/vfio/pci/vfio_pci_private.h | 1 +
drivers/vfio/vfio.c | 8
include/linux/vfio.h| 1 +
include/uapi/linux/vfio.h | 9 +
5 files changed, 48 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 6c11994..4ae9526 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data,
if (vdev-reset_works)
info.flags |= VFIO_DEVICE_FLAGS_RESET;
+ info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY;
+
This appears to be a PCI specific flag, so the name should include
_PCI_. We also support non-PCIe devices and it seems like it would be
possible to not have AER support available, so shouldn't this be
conditional?
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data,
return ret;
+ } else if (cmd == VFIO_DEVICE_SET_ERRFD) {
+ int32_t fd = (int32_t)arg;
+
+ if (fd 0)
+ return -EINVAL;
+
+ vdev-err_trigger = eventfd_ctx_fdget(fd);
+
+ if (IS_ERR(vdev-err_trigger))
+ return PTR_ERR(vdev-err_trigger);
+
+ return 0;
+
I'm not sure why we wouldn't describe this as just another interrupt
from the device and configure it via SET_IRQ. This ioctl has very
limited use and doesn't follow any of the conventions of all the other
vfio ioctls.
} else if (cmd == VFIO_DEVICE_RESET)
return vdev-reset_works ?
pci_reset_function(vdev-pdev) : -EINVAL;
@@ -527,11 +542,25 @@ static void vfio_pci_remove(struct pci_dev *pdev)
kfree(vdev);
}
+static pci_ers_result_t vfio_err_detected(struct pci_dev *pdev,
+ pci_channel_state_t state)
+{
+ struct vfio_pci_device *vdev = vfio_get_vdev(pdev-dev);
+
+ eventfd_signal(vdev-err_trigger, 1);
+ return PCI_ERS_RESULT_CAN_RECOVER;
+}
What if err_trigger hasn't been set?
+
+static const struct pci_error_handlers vfio_err_handlers = {
+ .error_detected = vfio_err_detected,
+};
+
static struct pci_driver vfio_pci_driver = {
.name = vfio-pci,
.id_table = NULL, /* only dynamic ids */
.probe = vfio_pci_probe,
.remove = vfio_pci_remove,
+ .err_handler= vfio_err_handlers,
};
static void __exit vfio_pci_cleanup(void)
diff --git a/drivers/vfio/pci/vfio_pci_private.h
b/drivers/vfio/pci/vfio_pci_private.h
index 611827c..daee62f 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -55,6 +55,7 @@ struct vfio_pci_device {
boolbardirty;
struct pci_saved_state *pci_saved_state;
atomic_trefcnt;
+ struct eventfd_ctx *err_trigger;
};
#define is_intx(vdev) (vdev-irq_type == VFIO_PCI_INTX_IRQ_INDEX)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 56097c6..5ed5a54 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -693,6 +693,14 @@ void *vfio_del_group_dev(struct device *dev)
}
EXPORT_SYMBOL_GPL(vfio_del_group_dev);
+void *vfio_get_vdev(struct device *dev)
+{
+ struct vfio_device *device = dev_get_drvdata(dev);
+
+ return device-device_data;
+}
+EXPORT_SYMBOL_GPL(vfio_get_vdev);
+
This is unsafe. How do we know dev is a vfio device? How do we keep
that drvdata valid while you're using it? I think you want to export
the existing vfio_group_get_device() and vfio_device_put(). Thanks,
Alex
/**
* VFIO base fd, /dev/vfio/vfio
*/
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index ab9e862..3c97b03 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -45,6 +45,7 @@ extern int vfio_add_group_dev(struct device *dev,
void *device_data);
extern void *vfio_del_group_dev(struct device *dev);
+extern void *vfio_get_vdev(struct device *dev);
/**
*
Re: [PATCH 1/2] VFIO-AER: Vfio-pci driver changes for supporting AER
On Wed, 2013-01-09 at 10:52 -0700, Alex Williamson wrote:
On Wed, 2013-01-09 at 06:26 +, Pandarathil, Vijaymohan R wrote:
- New ioctl which is used to pass the eventfd that is signaled when
an error occurs in the vfio_pci_device
- Register pci_error_handler for the vfio_pci driver
- When the device encounters an error, the error handler registered by
the vfio_pci driver gets invoked by the AER infrastructure
- In the error handler, signal the eventfd registered for the device.
- This results in the qemu eventfd handler getting invoked and
appropriate action taken for the guest.
Signed-off-by: Vijay Mohan Pandarathil vijaymohan.pandarat...@hp.com
---
drivers/vfio/pci/vfio_pci.c | 29 +
drivers/vfio/pci/vfio_pci_private.h | 1 +
drivers/vfio/vfio.c | 8
include/linux/vfio.h| 1 +
include/uapi/linux/vfio.h | 9 +
5 files changed, 48 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 6c11994..4ae9526 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -207,6 +207,8 @@ static long vfio_pci_ioctl(void *device_data,
if (vdev-reset_works)
info.flags |= VFIO_DEVICE_FLAGS_RESET;
+ info.flags |= VFIO_DEVICE_FLAGS_AER_NOTIFY;
+
This appears to be a PCI specific flag, so the name should include
_PCI_. We also support non-PCIe devices and it seems like it would be
possible to not have AER support available, so shouldn't this be
conditional?
info.num_regions = VFIO_PCI_NUM_REGIONS;
info.num_irqs = VFIO_PCI_NUM_IRQS;
@@ -348,6 +350,19 @@ static long vfio_pci_ioctl(void *device_data,
return ret;
+ } else if (cmd == VFIO_DEVICE_SET_ERRFD) {
+ int32_t fd = (int32_t)arg;
+
+ if (fd 0)
+ return -EINVAL;
+
+ vdev-err_trigger = eventfd_ctx_fdget(fd);
+
+ if (IS_ERR(vdev-err_trigger))
+ return PTR_ERR(vdev-err_trigger);
+
+ return 0;
+
I'm not sure why we wouldn't describe this as just another interrupt
from the device and configure it via SET_IRQ. This ioctl has very
limited use and doesn't follow any of the conventions of all the other
vfio ioctls.
} else if (cmd == VFIO_DEVICE_RESET)
return vdev-reset_works ?
pci_reset_function(vdev-pdev) : -EINVAL;
@@ -527,11 +542,25 @@ static void vfio_pci_remove(struct pci_dev *pdev)
kfree(vdev);
}
+static pci_ers_result_t vfio_err_detected(struct pci_dev *pdev,
+ pci_channel_state_t state)
+{
+ struct vfio_pci_device *vdev = vfio_get_vdev(pdev-dev);
+
+ eventfd_signal(vdev-err_trigger, 1);
+ return PCI_ERS_RESULT_CAN_RECOVER;
+}
What if err_trigger hasn't been set?
+
+static const struct pci_error_handlers vfio_err_handlers = {
+ .error_detected = vfio_err_detected,
+};
+
static struct pci_driver vfio_pci_driver = {
.name = vfio-pci,
.id_table = NULL, /* only dynamic ids */
.probe = vfio_pci_probe,
.remove = vfio_pci_remove,
+ .err_handler= vfio_err_handlers,
};
static void __exit vfio_pci_cleanup(void)
diff --git a/drivers/vfio/pci/vfio_pci_private.h
b/drivers/vfio/pci/vfio_pci_private.h
index 611827c..daee62f 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -55,6 +55,7 @@ struct vfio_pci_device {
boolbardirty;
struct pci_saved_state *pci_saved_state;
atomic_trefcnt;
+ struct eventfd_ctx *err_trigger;
};
#define is_intx(vdev) (vdev-irq_type == VFIO_PCI_INTX_IRQ_INDEX)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 56097c6..5ed5a54 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -693,6 +693,14 @@ void *vfio_del_group_dev(struct device *dev)
}
EXPORT_SYMBOL_GPL(vfio_del_group_dev);
+void *vfio_get_vdev(struct device *dev)
+{
+ struct vfio_device *device = dev_get_drvdata(dev);
+
+ return device-device_data;
+}
+EXPORT_SYMBOL_GPL(vfio_get_vdev);
+
This is unsafe. How do we know dev is a vfio device? How do we keep
that drvdata valid while you're using it? I think you want to export
the existing vfio_group_get_device() and vfio_device_put(). Thanks,
vfio_group_get_device() isn't quite what you want either since it
assumes a reference count on the group. You'll want something like
vfio_add_group_dev() or vfio_dev_present(), perhaps moving the
iommu_group_get - vfio_group_get_from_iommu - vfio_group_get_device
into a helper function. Thanks,
Alex
/**
* VFIO base fd,
