[PATCH v4 2/3] vfio/pci: Support 8-byte PCI loads and stores

[Gerd Bayer <gbayer@linux.ibm.com>]

From: Ben Segal <bpsegal@us.ibm.com>

Many PCI adapters can benefit or even require full 64bit read
and write access to their registers. In order to enable work on
user-space drivers for these devices add two new variations
vfio_pci_core_io{read|write}64 of the existing access methods
when the architecture supports 64-bit ioreads and iowrites.

Signed-off-by: Ben Segal <bpsegal@us.ibm.com>
Co-developed-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
---
 drivers/vfio/pci/vfio_pci_rdwr.c | 18 +++++++++++++++++-
 include/linux/vfio_pci_core.h    |  5 ++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index d07bfb0ab892..07351ea76604 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -61,7 +61,7 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_iowrite##size);
 VFIO_IOWRITE(8)
 VFIO_IOWRITE(16)
 VFIO_IOWRITE(32)
-#ifdef iowrite64
+#ifdef CONFIG_64BIT
 VFIO_IOWRITE(64)
 #endif
 
@@ -89,6 +89,9 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_ioread##size);
 VFIO_IOREAD(8)
 VFIO_IOREAD(16)
 VFIO_IOREAD(32)
+#ifdef CONFIG_64BIT
+VFIO_IOREAD(64)
+#endif
 
 #define VFIO_IORDWR(size)						\
 static int vfio_pci_iordwr##size(struct vfio_pci_core_device *vdev,\
@@ -124,6 +127,10 @@ static int vfio_pci_iordwr##size(struct vfio_pci_core_device *vdev,\
 VFIO_IORDWR(8)
 VFIO_IORDWR(16)
 VFIO_IORDWR(32)
+#if CONFIG_64BIT
+VFIO_IORDWR(64)
+#endif
+
 /*
  * Read or write from an __iomem region (MMIO or I/O port) with an excluded
  * range which is inaccessible.  The excluded range drops writes and fills
@@ -148,6 +155,15 @@ ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
 		else
 			fillable = 0;
 
+#if CONFIG_64BIT
+		if (fillable >= 8 && !(off % 8)) {
+			ret = vfio_pci_iordwr64(vdev, iswrite, test_mem,
+						io, buf, off, &filled);
+			if (ret)
+				return ret;
+
+		} else
+#endif
 		if (fillable >= 4 && !(off % 4)) {
 			ret = vfio_pci_iordwr32(vdev, iswrite, test_mem,
 						io, buf, off, &filled);
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index a2c8b8bba711..5f9b02d4a3e9 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -146,7 +146,7 @@ int vfio_pci_core_iowrite##size(struct vfio_pci_core_device *vdev,	\
 VFIO_IOWRITE_DECLATION(8)
 VFIO_IOWRITE_DECLATION(16)
 VFIO_IOWRITE_DECLATION(32)
-#ifdef iowrite64
+#ifdef CONFIG_64BIT
 VFIO_IOWRITE_DECLATION(64)
 #endif
 
@@ -157,5 +157,8 @@ int vfio_pci_core_ioread##size(struct vfio_pci_core_device *vdev,	\
 VFIO_IOREAD_DECLATION(8)
 VFIO_IOREAD_DECLATION(16)
 VFIO_IOREAD_DECLATION(32)
+#ifdef CONFIG_64BIT
+VFIO_IOREAD_DECLATION(64)
+#endif
 
 #endif /* VFIO_PCI_CORE_H */
-- 
2.45.0