PCI 2.3 added the interrupt disable bit, which provides us with a
generic way of squelching the device interrupt, and allowing us
to support devices that share interrupts. We can however support
non-PCI 2.3 devices so long as they can acquire a non-shared
interrupt. This allows us to use the generic enable/disable_irq
routines and achieve the same goal.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/vfio/vfio_intrs.c | 77 +++++++++++++++++++++++++++++----------------
drivers/vfio/vfio_main.c | 13 ++++----
include/linux/vfio.h | 2 +
3 files changed, 57 insertions(+), 35 deletions(-)
diff --git a/drivers/vfio/vfio_intrs.c b/drivers/vfio/vfio_intrs.c
index a57d5aa..4d5a7f8 100644
--- a/drivers/vfio/vfio_intrs.c
+++ b/drivers/vfio/vfio_intrs.c
@@ -52,32 +52,44 @@ irqreturn_t vfio_interrupt(int irq, void *dev_id)
u16 origcmd, newcmd, status;
spin_lock_irq(&vdev->irqlock);
- pci_block_user_cfg_access(pdev);
-
- /* Read both command and status registers in a single 32-bit operation.
- * Note: we could cache the value for command and move the status read
- * out of the lock if there was a way to get notified of user changes
- * to command register through sysfs. Should be good for shared irqs. */
- pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);
- origcmd = cmd_status_dword;
- status = cmd_status_dword >> 16;
-
- /* Check interrupt status register to see whether our device
- * triggered the interrupt. */
- if (!(status & PCI_STATUS_INTERRUPT))
- goto done;
-
- /* We triggered the interrupt, disable it. */
- newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;
- if (newcmd != origcmd)
- pci_write_config_word(pdev, PCI_COMMAND, newcmd);
-
- ret = IRQ_HANDLED;
+
+ if (vdev->pci_2_3) {
+ pci_block_user_cfg_access(pdev);
+
+ /* Read both command and status registers in a single 32-bit
+ * operation. Note: we could cache the value for command and
+ * move the status read out of the lock if there was a way to
+ * get notified of user changes to command register through
+ * sysfs. Should be good for shared irqs. */
+ pci_read_config_dword(pdev, PCI_COMMAND, &cmd_status_dword);
+ origcmd = cmd_status_dword;
+ status = cmd_status_dword >> 16;
+
+ /* Check interrupt status register to see whether our device
+ * triggered the interrupt. */
+ if (!(status & PCI_STATUS_INTERRUPT))
+ goto done;
+
+ /* We triggered the interrupt, disable it. */
+ newcmd = origcmd | PCI_COMMAND_INTX_DISABLE;
+ if (newcmd != origcmd)
+ pci_write_config_word(pdev, PCI_COMMAND, newcmd);
+
+ ret = IRQ_HANDLED;
done:
- pci_unblock_user_cfg_access(pdev);
+ pci_unblock_user_cfg_access(pdev);
+ } else {
+ disable_irq_nosync(pdev->irq);
+ ret = IRQ_HANDLED;
+ }
+
+ vdev->irq_disabled = (ret == IRQ_HANDLED);
+
spin_unlock_irq(&vdev->irqlock);
+
if (ret != IRQ_HANDLED)
return ret;
+
if (vdev->ev_irq)
eventfd_signal(vdev->ev_irq, 1);
return ret;
@@ -86,16 +98,25 @@ done:
int vfio_irq_eoi(struct vfio_dev *vdev)
{
struct pci_dev *pdev = vdev->pdev;
- u16 cmd;
spin_lock_irq(&vdev->irqlock);
- pci_block_user_cfg_access(pdev);
- pci_read_config_word(pdev, PCI_COMMAND, &cmd);
- cmd &= ~PCI_COMMAND_INTX_DISABLE;
- pci_write_config_word(pdev, PCI_COMMAND, cmd);
+ if (vdev->irq_disabled) {
+ if (vdev->pci_2_3) {
+ u16 cmd;
+ pci_block_user_cfg_access(pdev);
+
+ pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+ cmd &= ~PCI_COMMAND_INTX_DISABLE;
+ pci_write_config_word(pdev, PCI_COMMAND, cmd);
+
+ pci_unblock_user_cfg_access(pdev);
+ } else
+ enable_irq(pdev->irq);
+
+ vdev->irq_disabled = false;
+ }
- pci_unblock_user_cfg_access(pdev);
spin_unlock_irq(&vdev->irqlock);
return 0;
}
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 72db79c..cf2e671 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -401,7 +401,8 @@ static long vfio_unl_ioctl(struct file *filep,
if (vdev->ev_irq)
ret = request_irq(pdev->irq,
vfio_interrupt,
- IRQF_SHARED, vdev->name, vdev);
+ vdev->pci_2_3 ? IRQF_SHARED : 0,
+ vdev->name, vdev);
else
ret = -EINVAL;
}
@@ -567,8 +568,8 @@ static int verify_pci_2_3(struct pci_dev *pdev)
return -EBUSY;
}
if (!((new ^ orig) & PCI_COMMAND_INTX_DISABLE)) {
- dev_warn(&pdev->dev, "Device does not support "
- "disabling interrupts: unable to bind.\n");
+ dev_warn(&pdev->dev, "Device does not support disabling "
+ "interrupts, exclusive interrupt required.\n");
return -ENODEV;
}
/* Now restore the original value. */
@@ -589,15 +590,13 @@ static int vfio_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if ((type & 0x7F) != PCI_HEADER_TYPE_NORMAL)
return -EINVAL;
- err = verify_pci_2_3(pdev);
- if (err)
- return err;
-
vdev = kzalloc(sizeof(struct vfio_dev), GFP_KERNEL);
if (!vdev)
return -ENOMEM;
vdev->pdev = pdev;
+ vdev->pci_2_3 = (verify_pci_2_3(pdev) == 0);
+
mutex_init(&vdev->lgate);
mutex_init(&vdev->dgate);
mutex_init(&vdev->igate);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 73d7e84..f7e51ff 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -77,6 +77,8 @@ struct vfio_dev {
u8 msi_qmax;
u8 bardirty;
struct perm_bits *msi_perm;
+ bool pci_2_3;
+ bool irq_disabled;
};
struct vfio_listener {
--
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