Re: [PATCH 2/3] dp8393x: fix dp8393x_receive()

[Hervé Poussineau]

Le 02/11/2019 à 18:15, Laurent Vivier a écrit :
> address_space_rw() access size must be multiplied by the width.
>
> This fixes DHCP for Q800 guest.
>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>   hw/net/dp8393x.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
> index 85d3f3788e..b8c4473f99 100644
> --- a/hw/net/dp8393x.c
> +++ b/hw/net/dp8393x.c
> @@ -833,7 +833,7 @@ static ssize_t dp8393x_receive(NetClientState *nc, const 
> uint8_t * buf,
>       } else {
>           dp8393x_put(s, width, 0, 0); /* in_use */
>           address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 6 * 
> width,
> -            MEMTXATTRS_UNSPECIFIED, (uint8_t *)s->data, sizeof(uint16_t), 1);
> +            MEMTXATTRS_UNSPECIFIED, (uint8_t *)s->data, size, 1);
>           s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
>           s->regs[SONIC_ISR] |= SONIC_ISR_PKTRX;
>           s->regs[SONIC_RSC] = (s->regs[SONIC_RSC] & 0xff00) | (((s->regs[SONIC_RSC] 
> & 0x00ff) + 1) & 0x00ff);

This patch is problematic.
The code was initially created with "size".
It was changed in 409b52bfe199d8106dadf7c5ff3d88d2228e89b5 to fix networking in 
NetBSD 5.1.

To test with NetBSD 5.1
- boot the installer (arccd-5.1.iso)
- choose (S)hell option
- "ifconfig sn0 10.0.2.15 netmask 255.255.255.0"
- "route add default 10.0.2.2"
- networking should work (I test with "ftp 212.27.63.3")

Without this patch, I get the FTP banner.
With this patch, connection can't be established.

In datasheet page 17, you can see the "Receive Descriptor Format", which 
contains the in_use field.
It is clearly said that RXpkt.in_use is 16 bit wide, and that the bits 16-31 
are not used in 32-bit mode.

So, I don't see why you need to clear 32 bits in 32-bit mode. Maybe you need to 
clear only the other
16 bits ? Maybe it depends of endianness ?

Regards,

Hervé