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

Alex Williamson
2014-10-21T20:24:35Z

On Tue, 2014-10-21 at 14:04 +0200, Frank Blaschka wrote:
> 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.
>
> Signed-off-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
> ---
> 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

> 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

> #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

> 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
> @@ -210,12 +210,25 @@ error:
> 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;
}
> +
> 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.

> 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;
> case VFIO_PCI_ROM_REGION_INDEX:
> {
> 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