[PATCH linux-next] vfio: make vfio build and run on s390

Alex Williamson

2014-10-21 20:24:35 UTC

Post by Frank Blaschka
Introduce platform functions to let vfio announce if INTx is available and
if PCI BARs are mapable. Also take care vfio_pci_vga_rw is building on
platforms which do not support I/O ports.
---
arch/s390/include/asm/pci.h | 3 +++
drivers/vfio/Kconfig | 2 +-
drivers/vfio/pci/vfio_pci.c | 33 ++++++++++++++++++++++++++++-----
drivers/vfio/pci/vfio_pci_rdwr.c | 4 ++++
4 files changed, 36 insertions(+), 6 deletions(-)

Arnd Bergmann sent me a patch [1] recently that clued me in to the
IS_ENABLED() build time check that I wonder if if might be more
appropriate here. I think it could certainly make for cleaner code.

[1] https://lkml.org/lkml/2014/10/9/82

Post by Frank Blaschka
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 6790d0d..0ca2008 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -12,6 +12,9 @@
#include <asm/pci_clp.h>
#include <asm/pci_debug.h>
+#define __ARCH_PCI_NO_BARMAP
+#define __ARCH_PCI_NO_INTX
+

We'd drop this

Post by Frank Blaschka
#define PCIBIOS_MIN_IO 0x1000
#define PCIBIOS_MIN_MEM 0x10000000
diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index d8c5763..b93c259 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -16,7 +16,7 @@ config VFIO_SPAPR_EEH
menuconfig VFIO
tristate "VFIO Non-Privileged userspace driver framework"
depends on IOMMU_API
- select VFIO_IOMMU_TYPE1 if X86
+ select VFIO_IOMMU_TYPE1 if (X86 || S390)
select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
select VFIO_SPAPR_EEH if (PPC_POWERNV || PPC_PSERIES)
select ANON_INODES

In drivers/vfio/pci/Kconfig we'd also add something like:

config VFIO_PCI_MMAP
depends on VFIO_PCI
def_bool y if !S390

config VFIO_PCI_INTX
depends on VFIO_PCI
def_bool y if !S390

These should not be visible config items

Post by Frank Blaschka
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 9558da3..808072f 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
return ret;
}
+static int vfio_pci_intx_available(struct pci_dev *pdev)
+{
+#ifdef __ARCH_PCI_NO_INTX
+ return 0;
+#else
+ u8 pin;
+ int rc = 0;
+
+ pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
+ if (pin)
+ rc = 1;
+ return rc;
+#endif
+}

This could then be:

static int vfio_pci_intx_available(struct pci_dev *pdev)
{
u8 pin;

pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
if (IS_ENABLED(CONFIG_VFIO_PCI_INTX) && pin)
return 1;

return 0;
}

Post by Frank Blaschka
+
static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
{
if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
- u8 pin;
- pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);
- if (pin)
+ if (vfio_pci_intx_available(vdev->pdev))
return 1;
} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
@@ -350,6 +363,16 @@ static int vfio_pci_for_each_slot_or_bus(struct pci_dev *pdev,
return walk.ret;
}
+static int vfio_pci_bar_mapable(struct pci_dev *pdev, __u32 index, __u64 size)
+{
+#ifdef __ARCH_PCI_NO_BARMAP
+ return 0;
+#else
+ return (pci_resource_flags(pdev, index) &
+ IORESOURCE_MEM && size >= PAGE_SIZE);
+#endif
+}
+

And here it would just be another test:

return (IS_ENABLED(CONFIG_VFIO_PCI_MMAP) &&
pci_resource_flags(pdev, index) & IORESOURCE_MEM &&
size >= PAGE_SIZE);

For both of these I'm not sure the separate function is really
necessary.

Post by Frank Blaschka
static long vfio_pci_ioctl(void *device_data,
unsigned int cmd, unsigned long arg)
{
@@ -406,9 +429,9 @@ static long vfio_pci_ioctl(void *device_data,
info.flags = VFIO_REGION_INFO_FLAG_READ |
VFIO_REGION_INFO_FLAG_WRITE;
- if (pci_resource_flags(pdev, info.index) &
- IORESOURCE_MEM && info.size >= PAGE_SIZE)
+ if (vfio_pci_bar_mapable(pdev, info.index, info.size))
info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
+
break;
{
diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 210db24..02c5623 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -180,6 +180,9 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
size_t count, loff_t *ppos, bool iswrite)
{
+#ifdef CONFIG_NO_IOPORT_MAP
+ return -EINVAL;
+#else
int ret;
loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
void __iomem *iomem = NULL;
@@ -235,4 +238,5 @@ ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
*ppos += done;
return done;
+#endif

Here we could use:

if (!IS_ENABLED(CONFIG_VFIO_PCI_VGA) || !vdev->has_vga)
return -EINVAL;

A better option for this one would still probably be for s390 to stub
out the missing io* calls. Thanks,

Alex