Re: [Qemu-devel] [PATCH 1/6] qtest: add test framework

[Stefan Hajnoczi]

On Fri, Jan 13, 2012 at 6:32 PM, Anthony Liguori <address@hidden> wrote:
> +    if (strcmp(words[0], "outb") == 0 ||
> +        strcmp(words[0], "outw") == 0 ||
> +        strcmp(words[0], "outl") == 0) {
> +        uint16_t addr;
> +        uint32_t value;
> +
> +        g_assert(words[1] && words[2]);
> +        addr = strtol(words[1], NULL, 0);
> +        value = strtol(words[2], NULL, 0);
> +
> +        if (words[0][3] == 'b') {
> +            cpu_outb(addr, value);
> +        } else if (words[0][3] == 'w') {
> +            cpu_outw(addr, value);
> +        } else if (words[0][3] == 'l') {
> +            cpu_outl(addr, value);
> +        }
> +        qtest_send_prefix(chr);
> +        qtest_send(chr, "OK\n");
> +    } else if (strcmp(words[0], "inb") == 0 ||
> +        strcmp(words[0], "inw") == 0 ||
> +        strcmp(words[0], "inl") == 0) {
> +        uint16_t addr;
> +        uint32_t value = -1U;
> +
> +        g_assert(words[1]);
> +        addr = strtol(words[1], NULL, 0);
> +
> +        if (words[0][2] == 'b') {
> +            value = cpu_inb(addr);
> +        } else if (words[0][2] == 'w') {
> +            value = cpu_inw(addr);
> +        } else if (words[0][2] == 'l') {
> +            value = cpu_inl(addr);
> +        }
> +        qtest_send_prefix(chr);
> +        qtest_send(chr, "OK 0x%04x\n", value);

Endianness is a little weird here.  memory.c will byteswap if target
and device endianness differ.

Imagine the case where we're on an x86 host, running a ppc guest,
reading from PCI configuration space (little-endian).  Since ppc
(target endian) is big-endian and the device is little-endian the
value read/written will be byteswapped.  However, our qtest runs on
the host and therefore we don't want that automatic swap (or we need
to neutralize it by performing another byteswap on top).

Stefan