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vfio/pci: Use endian neutral helpers 

The iowriteXX/ioreadXX functions assume little endian hardware and
convert to little endian on a write and from little endian on a read.
We currently do our own explicit conversion to negate this.  Instead,
add some endian dependent defines to avoid all byte swaps.  There
should be no functional change other than big endian systems aren't
penalized with wasted swaps.

Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2018-03-21 12:46:21 -06:00
parent 0d77ed3589
commit 07fd7ef3a1
1 changed files with 26 additions and 8 deletions
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34
drivers/vfio/pci/vfio_pci_rdwr.c
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@ -21,6 +21,24 @@
#include "vfio_pci_private.h"
#ifdef __LITTLE_ENDIAN
#define vfio_ioread64 ioread64
#define vfio_iowrite64 iowrite64
#define vfio_ioread32 ioread32
#define vfio_iowrite32 iowrite32
#define vfio_ioread16 ioread16
#define vfio_iowrite16 iowrite16
#else
#define vfio_ioread64 ioread64be
#define vfio_iowrite64 iowrite64be
#define vfio_ioread32 ioread32be
#define vfio_iowrite32 iowrite32be
#define vfio_ioread16 ioread16be
#define vfio_iowrite16 iowrite16be
#endif
#define vfio_ioread8 ioread8
#define vfio_iowrite8 iowrite8
/*
* 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
@ -44,15 +62,15 @@ static ssize_t do_io_rw(void __iomem *io, char __user *buf,
fillable = 0;
if (fillable >= 4 && !(off % 4)) {
__le32 val;
u32 val;
if (iswrite) {
if (copy_from_user(&val, buf, 4))
return -EFAULT;
iowrite32(le32_to_cpu(val), io + off);
vfio_iowrite32(val, io + off);
} else {
val = cpu_to_le32(ioread32(io + off));
val = vfio_ioread32(io + off);
if (copy_to_user(buf, &val, 4))
return -EFAULT;
@ -60,15 +78,15 @@ static ssize_t do_io_rw(void __iomem *io, char __user *buf,
filled = 4;
} else if (fillable >= 2 && !(off % 2)) {
__le16 val;
u16 val;
if (iswrite) {
if (copy_from_user(&val, buf, 2))
return -EFAULT;
iowrite16(le16_to_cpu(val), io + off);
vfio_iowrite16(val, io + off);
} else {
val = cpu_to_le16(ioread16(io + off));
val = vfio_ioread16(io + off);
if (copy_to_user(buf, &val, 2))
return -EFAULT;
@ -82,9 +100,9 @@ static ssize_t do_io_rw(void __iomem *io, char __user *buf,
if (copy_from_user(&val, buf, 1))
return -EFAULT;
iowrite8(val, io + off);
vfio_iowrite8(val, io + off);
} else {
val = ioread8(io + off);
val = vfio_ioread8(io + off);
if (copy_to_user(buf, &val, 1))
return -EFAULT;