[RFC PATCH v3 6/9] vfio/pci: export vfio_pci_setup_barmap

Yan Zhao
2020-02-11T10:23:46Z

This allows vendor driver to read/write to bars directly which is useful
in security checking condition.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
drivers/vfio/pci/vfio_pci_rdwr.c | 26 +++++++++++++-------------
include/linux/vfio.h | 2 ++
2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index a0ef1de4f74a..3ba85fb2af5b 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -129,7 +129,7 @@ static ssize_t do_io_rw(void __iomem *io, char __user *buf,
return done;
}

-static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
+void __iomem *vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
{
struct pci_dev *pdev = vdev->pdev;
struct vfio_pci_device_private *priv = VDEV_TO_PRIV(vdev);
@@ -137,22 +137,23 @@ static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
void __iomem *io;

if (priv->barmap[bar])
- return 0;
+ return priv->barmap[bar];

ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
if (ret)
- return ret;
+ return NULL;

io = pci_iomap(pdev, bar, 0);
if (!io) {
pci_release_selected_regions(pdev, 1 << bar);
- return -ENOMEM;
+ return NULL;
}

priv->barmap[bar] = io;

- return 0;
+ return io;
}
+EXPORT_SYMBOL_GPL(vfio_pci_setup_barmap);

ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
size_t count, loff_t *ppos, bool iswrite)
@@ -190,11 +191,9 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
return -ENOMEM;
x_end = end;
} else {
- int ret = vfio_pci_setup_barmap(vdev, bar);
- if (ret)
- return ret;
-
- io = priv->barmap[bar];
+ io = vfio_pci_setup_barmap(vdev, bar);
+ if (!io)
+ return -EFAULT;
}

if (bar == priv->msix_bar) {
@@ -309,6 +308,7 @@ long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
struct vfio_pci_ioeventfd *ioeventfd;
+ void __iomem *io;

/* Only support ioeventfds into BARs */
if (bar > VFIO_PCI_BAR5_REGION_INDEX)
@@ -328,9 +328,9 @@ long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
return -EINVAL;
#endif

- ret = vfio_pci_setup_barmap(vdev, bar);
- if (ret)
- return ret;
+ io = vfio_pci_setup_barmap(vdev, bar);
+ if (!io)
+ return -EFAULT;

mutex_lock(&priv->ioeventfds_lock);

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 4d7e80b2ed1b..00112ffd9ad0 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -223,6 +223,8 @@ extern int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma);
extern void vfio_pci_request(void *device_data, unsigned int count);
extern int vfio_pci_open(void *device_data);
extern void vfio_pci_release(void *device_data);
+extern void __iomem *vfio_pci_setup_barmap(struct vfio_pci_device *vdev,
+ int bar);

#define vfio_pci_register_vendor_driver(__name, __probe, __remove, \
__device_ops) \
--
2.17.1