Re: [Xen-devel] [PATCH v8 13/14] tools/libxl: explicitly grant access to needed I/O-memory ranges

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.05.14 at 12:51, <avanzini.arianna@xxxxxxxxx> wrote:
> --- a/tools/libxl/libxl_create.c
> +++ b/tools/libxl/libxl_create.c
> @@ -1149,6 +1149,23 @@ static void domcreate_launch_dm(libxl__egc *egc, 
> libxl__multidev *multidev,
>              libxl__spawn_stub_dm(egc, &dcs->dmss);
>          else
>              libxl__spawn_local_dm(egc, &dcs->dmss.dm);
> +
> +        /*
> +         * If VGA passthru is enabled by domain config, be sure that the
> +         * domain can access VGA-related iomem regions.
> +         */
> +        if (d_config->b_info.u.hvm.gfx_passthru.val) {
> +            uint64_t vga_iomem_start = 0xa0000 >> XC_PAGE_SHIFT;
> +            ret = xc_domain_iomem_permission(CTX->xch, domid,
> +                                             vga_iomem_start, 0x20, 1);
> +            if (ret < 0) {
> +                LOGE(ERROR,
> +                     "failed to give dom%d access to iomem range "
> +                     "%"PRIx64"-%"PRIx64" for VGA passthru",
> +                     domid, vga_iomem_start, (vga_iomem_start + 0x20 - 1));
> +                goto error_out;
> +            }
> +        }

I continue to see a problem with this when more than one GFX card
would get passed through - every guest getting one would get
control over the VGA region, which can't be right.

Jan


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