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

Gerd Bayer
2024-05-22T15:07:16Z

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