[dpdk-dev] [PATCH 6/7] virtio: fix pci accesses for ppc64 in legacy mode
David Marchand
david.marchand at 6wind.com
Fri May 13 16:28:27 CEST 2016
Hello Olivier,
On Fri, May 13, 2016 at 2:50 PM, Olivier Matz <olivier.matz at 6wind.com> wrote:
> From: David Marchand <david.marchand at 6wind.com>
>
> Although ppc supports both endianesses, qemu supposes that the cpu is
> big endian and enforces this for the virtio-net stuff.
>
> Fix PCI accesses in legacy mode. Only ppc64le is supported at the moment.
>
> Signed-off-by: David Marchand <david.marchand at 6wind.com>
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
> drivers/net/virtio/virtio_pci.c | 44 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/net/virtio/virtio_pci.c b/drivers/net/virtio/virtio_pci.c
> index 9cdca06..bdb89fd 100644
> --- a/drivers/net/virtio/virtio_pci.c
> +++ b/drivers/net/virtio/virtio_pci.c
> @@ -55,18 +55,62 @@
> */
> #define VIRTIO_PCI_CONFIG(hw) (((hw)->use_msix) ? 24 : 20)
>
> +/*
> + * Since we are in legacy mode:
> + * http://ozlabs.org/~rusty/virtio-spec/virtio-0.9.5.pdf
> + *
> + * "Note that this is possible because while the virtio header is PCI (i.e.
> + * little) endian, the device-specific region is encoded in the native endian of
> + * the guest (where such distinction is applicable)."
> + *
> + * For powerpc which supports both, qemu supposes that cpu is big endian and
> + * enforces this for the virtio-net stuff.
> + */
> +
> static void
> legacy_read_dev_config(struct virtio_hw *hw, size_t offset,
> void *dst, int length)
> {
> rte_eal_pci_ioport_read(&hw->io, dst, length,
> VIRTIO_PCI_CONFIG(hw) + offset);
> +#ifdef RTE_ARCH_PPC_64
> + switch (length) {
> + case 4:
> + *(uint32_t *)dst = rte_be_to_cpu_32(*(uint32_t *)dst);
> + break;
> + case 2:
> + *(uint16_t *)dst = rte_be_to_cpu_16(*(uint16_t *)dst);
> + break;
> + default:
> + break;
> + }
> +#endif
> }
I think that, in the original patch, I was handling lengths different
than 1, 2 and 4 ;-)
Idem for write.
--
David Marchand
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