Re: [XEN][RFC PATCH v3 12/14] tools/libs/ctrl: Implement new xc interfaces for dt overlay

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Hi Vikram,

On Tue, Mar 08, 2022 at 11:47:02AM -0800, Vikram Garhwal wrote:
> diff --git a/tools/libs/ctrl/xc_overlay.c b/tools/libs/ctrl/xc_overlay.c
> new file mode 100644
> index 0000000000..8fe780d75a
> --- /dev/null
> +++ b/tools/libs/ctrl/xc_overlay.c

Could rename this new file? I don't think using "overlay" alone is going
to be helpful to figure out what it is about. Renaming it
"xc_dt_overlay.c" would already be better.

> @@ -0,0 +1,51 @@
> +/*
> + *
> + * Overlay control functions.

Maybe "Device Tree overlay functions" would be better. I'm not sure that
"control" is useful in the file description.

> + * Copyright (C) 2021 Xilinx Inc.
> + * Author Vikram Garhwal <fnu.vikram@xxxxxxxxxx>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation;
> + * version 2.1 of the License.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; If not, see 
> <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "xc_bitops.h"
> +#include "xc_private.h"
> +#include <xen/hvm/hvm_op.h>
> +#include <libfdt.h>
> +
> +int xc_dt_overlay(xc_interface *xch, void *overlay_fdt, int overlay_fdt_size,
> +                  uint8_t overlay_op)

Shouldn't the function prototype match the types from the sysctl
structure? There is "int" vs "uint32_t" for "overlay_fdt_size".

> +{
> +    int err;
> +    DECLARE_SYSCTL;
> +
> +    DECLARE_HYPERCALL_BOUNCE(overlay_fdt, overlay_fdt_size,
> +                        XC_HYPERCALL_BUFFER_BOUNCE_IN);
> +
> +    if ( (err = xc_hypercall_bounce_pre(xch, overlay_fdt)) )
> +        goto err;
> +
> +    sysctl.cmd = XEN_SYSCTL_dt_overlay;
> +    sysctl.u.dt_overlay.overlay_op = overlay_op;
> +    sysctl.u.dt_overlay.overlay_fdt_size = overlay_fdt_size;
> +
> +    set_xen_guest_handle(sysctl.u.dt_overlay.overlay_fdt, overlay_fdt);
> +
> +    if ( (err = do_sysctl(xch, &sysctl)) != 0 )
> +        PERROR("%s failed\n", __func__);

The \n should be remove from the message. perror already adds a newline,
and it also adds information about the error after the message so a
newline in the middle will make it harder to read the error.

> +
> +err:
> +    xc_hypercall_bounce_post(xch, overlay_fdt);
> +
> +    return err;
> +}

Thanks,

-- 
Anthony PERARD