Re: [PATCH V4 vfio 8/9] vfio/pci: Expose vfio_pci_iowrite/read##size()

[Yishai Hadas]

On 30/11/2023 21:20, Alex Williamson wrote:
On Wed, 29 Nov 2023 16:37:45 +0200
Yishai Hadas <yish...@nvidia.com> wrote:
Expose vfio_pci_iowrite/read##size() to let it be used by drivers.

This functionality is needed to enable direct access to some physical
BAR of the device with the proper locks/checks in place.

The next patches from this series will use this functionality on a data
path flow when a direct access to the BAR is needed.

Signed-off-by: Yishai Hadas <yish...@nvidia.com>
---
  drivers/vfio/pci/vfio_pci_rdwr.c | 10 ++++++----
  include/linux/vfio_pci_core.h    | 19 +++++++++++++++++++
  2 files changed, 25 insertions(+), 4 deletions(-)

I don't follow the inconsistency between this and the previous patch.
Why did we move and rename the code to setup the barmap but we export
the ioread/write functions in place?  Thanks,

Alex

The mount of code for barmap setup was quite small compared to the 
ioread/write functions.

However, I agree, we can be consistent here and export in both cases the 
functions in place as part of vfio_pci_rdwr.c which is already part of 
vfio_pci_core.ko

I may also rename in current patch vfio_pci_iowrite/read<xxx> to have 
the 'core' prefix as part of the functions names (i.e. 
vfio_pci_core_iowrite/read<xxx>) to be consistent with other exported 
core functions and adapt the callers to this name.

Makes sense ?

Yishai



diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 6f08b3ecbb89..817ec9a89123 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -38,7 +38,7 @@
  #define vfio_iowrite8 iowrite8
  
  #define VFIO_IOWRITE(size) \
-static int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev,           
\
+int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev,          \
                        bool test_mem, u##size val, void __iomem *io)   \
  {                                                                     \
        if (test_mem) {                                                 \
@@ -55,7 +55,8 @@ static int vfio_pci_iowrite##size(struct vfio_pci_core_device 
*vdev,          \
                up_read(&vdev->memory_lock);                             \
                                                                        \
        return 0;                                                       \
-}
+}                                                                      \
+EXPORT_SYMBOL_GPL(vfio_pci_iowrite##size);
  
  VFIO_IOWRITE(8)
  VFIO_IOWRITE(16)
@@ -65,7 +66,7 @@ VFIO_IOWRITE(64)
  #endif
  
  #define VFIO_IOREAD(size) \
-static int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev,            
\
+int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev,           \
                        bool test_mem, u##size *val, void __iomem *io)  \
  {                                                                     \
        if (test_mem) {                                                 \
@@ -82,7 +83,8 @@ static int vfio_pci_ioread##size(struct vfio_pci_core_device 
*vdev,           \
                up_read(&vdev->memory_lock);                             \
                                                                        \
        return 0;                                                       \
-}
+}                                                                      \
+EXPORT_SYMBOL_GPL(vfio_pci_ioread##size);
  
  VFIO_IOREAD(8)
  VFIO_IOREAD(16)
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 67ac58e20e1d..22c915317788 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -131,4 +131,23 @@ int vfio_pci_core_setup_barmap(struct vfio_pci_core_device 
*vdev, int bar);
  pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
                                                pci_channel_state_t state);
  
+#define VFIO_IOWRITE_DECLATION(size) \
+int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev,          \
+                       bool test_mem, u##size val, void __iomem *io);
+
+VFIO_IOWRITE_DECLATION(8)
+VFIO_IOWRITE_DECLATION(16)
+VFIO_IOWRITE_DECLATION(32)
+#ifdef iowrite64
+VFIO_IOWRITE_DECLATION(64)
+#endif
+
+#define VFIO_IOREAD_DECLATION(size) \
+int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev,           \
+                       bool test_mem, u##size *val, void __iomem *io);
+
+VFIO_IOREAD_DECLATION(8)
+VFIO_IOREAD_DECLATION(16)
+VFIO_IOREAD_DECLATION(32)
+
  #endif /* VFIO_PCI_CORE_H */