Re: [Qemu-devel] [PATCH v4 09/11] pc-bios/s390-ccw: Add core files for the network bootloading program

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 11 Jul 2017 15:56:35 +0200
Thomas Huth <thuth@redhat.com> wrote:

> This is just a preparation for the next steps: Add a makefile and a
> stripped down copy of pc-bios/s390-ccw/main.c as a basis for the network
> bootloader program, linked against the libc from SLOF already (which we
> will need for SLOF's libnet). The networking code is not included yet.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  pc-bios/s390-ccw/Makefile    |  11 +++-
>  pc-bios/s390-ccw/netboot.mak |  41 +++++++++++++
>  pc-bios/s390-ccw/netmain.c   | 137 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 187 insertions(+), 2 deletions(-)
>  create mode 100644 pc-bios/s390-ccw/netboot.mak
>  create mode 100644 pc-bios/s390-ccw/netmain.c
> 

> diff --git a/pc-bios/s390-ccw/netmain.c b/pc-bios/s390-ccw/netmain.c
> new file mode 100644
> index 0000000..d604623
> --- /dev/null
> +++ b/pc-bios/s390-ccw/netmain.c
> @@ -0,0 +1,137 @@

(...)

> +static uint64_t get_timer_ms(void)
> +{
> +    uint64_t clk;
> +
> +    asm volatile(" stck %0 " : : "Q"(clk) : "memory");
> +
> +    /* Bit 51 is incrememented each microsecond */

s/incrememented/incremented/

> +    return (clk >> (63 - 51)) / 1000;
> +}

(...)

> +static bool find_net_dev(Schib *schib, int dev_no)
> +{
> +    int i, r;
> +
> +    for (i = 0; i < 0x10000; i++) {
> +        net_schid.sch_no = i;
> +        r = stsch_err(net_schid, schib);
> +        if (r == 3 || r == -EIO) {
> +            break;
> +        }
> +        if (!schib->pmcw.dnv) {
> +            continue;
> +        }
> +        if (!virtio_is_supported(net_schid)) {
> +            continue;
> +        }
> +        if (virtio_get_device_type() != VIRTIO_ID_NET) {
> +            continue;
> +        }
> +        if (dev_no < 0 || schib->pmcw.dev == dev_no) {
> +            return true;
> +        }
> +    }
> +
> +    return false;
> +}
> +
> +static void virtio_setup(void)
> +{
> +    Schib schib;
> +    int ssid;
> +    bool found = false;
> +    uint16_t dev_no;
> +
> +    /*
> +     * We unconditionally enable mss support. In every sane configuration,
> +     * this will succeed; and even if it doesn't, stsch_err() can deal
> +     * with the consequences.
> +     */
> +    enable_mss_facility();
> +
> +    if (store_iplb(&iplb)) {
> +        IPL_assert(iplb.pbt == S390_IPL_TYPE_CCW, "IPL_TYPE_CCW expected");
> +        dev_no = iplb.ccw.devno;
> +        debug_print_int("device no. ", dev_no);
> +        net_schid.ssid = iplb.ccw.ssid & 0x3;
> +        debug_print_int("ssid ", net_schid.ssid);
> +        found = find_net_dev(&schib, dev_no);
> +    } else {
> +        for (ssid = 0; ssid < 0x3; ssid++) {
> +            net_schid.ssid = ssid;
> +            found = find_net_dev(&schib, -1);
> +            if (found) {
> +                break;
> +            }
> +        }
> +    }
> +
> +    IPL_assert(found && virtio_get_device_type() == VIRTIO_ID_NET,

Is found && virtio_get_device_type() != VIRTIO_ID_NET even possible?

> +               "No virtio net device found");
> +}

Anyway, otherwise

Reviewed-by: Cornelia Huck <cohuck@redhat.com>