[PATCH v3 17/26] vfio_pci: Loop using PCI_STD_NUM_BARS

From: Denis Efremov
Date: Mon Sep 16 2019 - 16:47:32 EST


Refactor loops to use idiomatic C style and avoid the fencepost error
of using "i < PCI_STD_RESOURCE_END" when "i <= PCI_STD_RESOURCE_END"
is required, e.g., commit 2f686f1d9bee ("PCI: Correct PCI_STD_RESOURCE_END
usage").

To iterate through all possible BARs, loop conditions changed to the
*number* of BARs "i < PCI_STD_NUM_BARS", instead of the index of the last
valid BAR "i <= PCI_STD_RESOURCE_END".

Cc: Cornelia Huck <cohuck@xxxxxxxxxx>
Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 11 ++++++----
drivers/vfio/pci/vfio_pci_config.c | 32 +++++++++++++++--------------
drivers/vfio/pci/vfio_pci_private.h | 4 ++--
3 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 703948c9fbe1..cb7d220d3246 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -110,13 +110,15 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
static void vfio_pci_probe_mmaps(struct vfio_pci_device *vdev)
{
struct resource *res;
- int bar;
+ int i;
struct vfio_pci_dummy_resource *dummy_res;

INIT_LIST_HEAD(&vdev->dummy_resources_list);

- for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
- res = vdev->pdev->resource + bar;
+ for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+ int bar = i + PCI_STD_RESOURCES;
+
+ res = &vdev->pdev->resource[bar];

if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP))
goto no_mmap;
@@ -399,7 +401,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)

vfio_config_free(vdev);

- for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
+ for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+ bar = i + PCI_STD_RESOURCES;
if (!vdev->barmap[bar])
continue;
pci_iounmap(pdev, vdev->barmap[bar]);
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index f0891bd8444c..90c0b80f8acf 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -450,30 +450,32 @@ static void vfio_bar_fixup(struct vfio_pci_device *vdev)
{
struct pci_dev *pdev = vdev->pdev;
int i;
- __le32 *bar;
+ __le32 *vbar;
u64 mask;

- bar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0];
+ vbar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0];

- for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++, bar++) {
- if (!pci_resource_start(pdev, i)) {
- *bar = 0; /* Unmapped by host = unimplemented to user */
+ for (i = 0; i < PCI_STD_NUM_BARS; i++, vbar++) {
+ int bar = i + PCI_STD_RESOURCES;
+
+ if (!pci_resource_start(pdev, bar)) {
+ *vbar = 0; /* Unmapped by host = unimplemented to user */
continue;
}

- mask = ~(pci_resource_len(pdev, i) - 1);
+ mask = ~(pci_resource_len(pdev, bar) - 1);

- *bar &= cpu_to_le32((u32)mask);
- *bar |= vfio_generate_bar_flags(pdev, i);
+ *vbar &= cpu_to_le32((u32)mask);
+ *vbar |= vfio_generate_bar_flags(pdev, bar);

- if (*bar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
- bar++;
- *bar &= cpu_to_le32((u32)(mask >> 32));
+ if (*vbar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
+ vbar++;
+ *vbar &= cpu_to_le32((u32)(mask >> 32));
i++;
}
}

- bar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];
+ vbar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];

/*
* NB. REGION_INFO will have reported zero size if we weren't able
@@ -483,14 +485,14 @@ static void vfio_bar_fixup(struct vfio_pci_device *vdev)
if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) {
mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1);
mask |= PCI_ROM_ADDRESS_ENABLE;
- *bar &= cpu_to_le32((u32)mask);
+ *vbar &= cpu_to_le32((u32)mask);
} else if (pdev->resource[PCI_ROM_RESOURCE].flags &
IORESOURCE_ROM_SHADOW) {
mask = ~(0x20000 - 1);
mask |= PCI_ROM_ADDRESS_ENABLE;
- *bar &= cpu_to_le32((u32)mask);
+ *vbar &= cpu_to_le32((u32)mask);
} else
- *bar = 0;
+ *vbar = 0;

vdev->bardirty = false;
}
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index ee6ee91718a4..8a2c7607d513 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -86,8 +86,8 @@ struct vfio_pci_reflck {

struct vfio_pci_device {
struct pci_dev *pdev;
- void __iomem *barmap[PCI_STD_RESOURCE_END + 1];
- bool bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
+ void __iomem *barmap[PCI_STD_NUM_BARS];
+ bool bar_mmap_supported[PCI_STD_NUM_BARS];
u8 *pci_config_map;
u8 *vconfig;
struct perm_bits *msi_perm;
--
2.21.0