Re: [Qemu-devel] [PATCH v2 1/5] vmxnet3: Change offsets of msi/msix pci capabilities

[Jason Wang <jasowang@redhat.com>]

On 12/02/2015 11:26 PM, Shmulik Ladkani wrote:
> Place device reported PCI capabilities at the same offsets as placed by
> the VMware virtual hardware: MSI at [84], MSI-X at [9c].
>
> For compatability, preserve old offsets using 'x-old-msi-offsets' toggle.
>
> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
> ---
>  hw/net/vmxnet3.c    | 20 +++++++++++++++++---
>  include/hw/compat.h |  4 ++++
>  2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
> index 5e3a233..1985dcf 100644
> --- a/hw/net/vmxnet3.c
> +++ b/hw/net/vmxnet3.c
> @@ -36,6 +36,16 @@
>  #define VMXNET3_MSIX_BAR_SIZE 0x2000
>  #define MIN_BUF_SIZE 60
>  
> +/* Compatability flags for migration */
> +#define VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS_BIT 0
> +#define VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS \
> +    (1 << VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS_BIT)
> +
> +#define VMXNET3_MSI_OFFSET(s) \
> +    ((s)->compat_flags & VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS ? 0x50 : 0x84)
> +#define VMXNET3_MSIX_OFFSET(s) \
> +    ((s)->compat_flags & VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS ? 0 : 0x9c)
> +
>  #define VMXNET3_BAR0_IDX      (0)
>  #define VMXNET3_BAR1_IDX      (1)
>  #define VMXNET3_MSIX_BAR_IDX  (2)
> @@ -313,6 +323,9 @@ typedef struct {
>          MACAddr *mcast_list;
>          uint32_t mcast_list_len;
>          uint32_t mcast_list_buff_size; /* needed for live migration. */
> +
> +        /* Compatability flags for migration */
> +        uint32_t compat_flags;
>  } VMXNET3State;
>  
>  /* Interrupt management */
> @@ -2103,7 +2116,7 @@ vmxnet3_init_msix(VMXNET3State *s)
>                          VMXNET3_MSIX_BAR_IDX, VMXNET3_OFF_MSIX_TABLE,
>                          &s->msix_bar,
>                          VMXNET3_MSIX_BAR_IDX, VMXNET3_OFF_MSIX_PBA,
> -                        0);
> +                        VMXNET3_MSIX_OFFSET(s));
>  
>      if (0 > res) {
>          VMW_WRPRN("Failed to initialize MSI-X, error %d", res);
> @@ -2131,7 +2144,6 @@ vmxnet3_cleanup_msix(VMXNET3State *s)
>      }
>  }
>  
> -#define VMXNET3_MSI_OFFSET        (0x50)
>  #define VMXNET3_USE_64BIT         (true)
>  #define VMXNET3_PER_VECTOR_MASK   (false)
>  
> @@ -2141,7 +2153,7 @@ vmxnet3_init_msi(VMXNET3State *s)
>      PCIDevice *d = PCI_DEVICE(s);
>      int res;
>  
> -    res = msi_init(d, VMXNET3_MSI_OFFSET, VMXNET3_MAX_NMSIX_INTRS,
> +    res = msi_init(d, VMXNET3_MSI_OFFSET(s), VMXNET3_MAX_NMSIX_INTRS,
>                     VMXNET3_USE_64BIT, VMXNET3_PER_VECTOR_MASK);
>      if (0 > res) {
>          VMW_WRPRN("Failed to initialize MSI, error %d", res);
> @@ -2552,6 +2564,8 @@ static const VMStateDescription vmstate_vmxnet3 = {
>  
>  static Property vmxnet3_properties[] = {
>      DEFINE_NIC_PROPERTIES(VMXNET3State, conf),
> +    DEFINE_PROP_BIT("x-old-msi-offsets", VMXNET3State, compat_flags,
> +                    VMXNET3_COMPAT_FLAG_OLD_MSI_OFFSETS_BIT, false),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/include/hw/compat.h b/include/hw/compat.h
> index d0b1c4f..01e326d 100644
> --- a/include/hw/compat.h
> +++ b/include/hw/compat.h
> @@ -18,6 +18,10 @@
>              .driver   = "virtio-pci",\
>              .property = "migrate-extra",\
>              .value    = "off",\
> +        },{\
> +            .driver   = "vmxnet3",\
> +            .property = "x-old-msi-offsets",\
> +            .value    = "on",\
>          },

To have a better bisection behavior, we'd better enable this and compat
it in patch 2.

>  
>  #define HW_COMPAT_2_3 \