[PATCH kernel RFC 1/2] vfio_pci: Allow device specific error handlers

[Alexey Kardashevskiy]

PCI device drivers can define own pci_error_handlers which are called
on errors or before/after reset. The VFIO PCI driver defines one as well.

This adds a vfio_pci_error_handlers struct for VFIO PCI which is a wrapper
on top of vfio_err_handlers. At the moment it defines reset_done() -
this hook is called right after the device reset and it can be used to do
some device tweaking before the userspace gets a chance to use the device.

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
 drivers/vfio/pci/vfio_pci_private.h |  5 +++++
 drivers/vfio/pci/vfio_pci.c         | 17 +++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_private.h 
b/drivers/vfio/pci/vfio_pci_private.h
index 1812cf22fc4f..aff96fa28726 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -87,8 +87,13 @@ struct vfio_pci_reflck {
        struct mutex            lock;
 };
 
+struct vfio_pci_error_handlers {
+       void (*reset_done)(struct vfio_pci_device *vdev);
+};
+
 struct vfio_pci_device {
        struct pci_dev          *pdev;
+       struct vfio_pci_error_handlers *error_handlers;
        void __iomem            *barmap[PCI_STD_RESOURCE_END + 1];
        bool                    bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
        u8                      *pci_config_map;
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 5bd97fa632d3..6ebc441d91c3 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1434,8 +1434,25 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct 
pci_dev *pdev,
        return PCI_ERS_RESULT_CAN_RECOVER;
 }
 
+static void vfio_pci_reset_done(struct pci_dev *dev)
+{
+       struct vfio_pci_device *vdev;
+       struct vfio_device *device;
+
+       device = vfio_device_get_from_dev(&dev->dev);
+       if (device == NULL)
+               return;
+
+       vdev = vfio_device_data(device);
+       if (vdev && vdev->error_handlers && vdev->error_handlers->reset_done)
+               vdev->error_handlers->reset_done(vdev);
+
+       vfio_device_put(device);
+}
+
 static const struct pci_error_handlers vfio_err_handlers = {
        .error_detected = vfio_pci_aer_err_detected,
+       .reset_done = vfio_pci_reset_done,
 };
 
 static struct pci_driver vfio_pci_driver = {
-- 
2.17.1