Re: [Xen-devel] [PATCH] xen/arm: warn if dom0_mem is not specified

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Feb 20, 2017 at 10:22:06AM -0800, Stefano Stabellini wrote:
> The default dom0_mem is 128M which is not sufficient to boot a Ubuntu
> based Dom0. It is not clear what a better default value could be.
> 
> Instead, loudly warn the user when dom0_mem is unspecified and wait 3
> secs. Then use 512M.
> 
> Update the docs to specify that dom0_mem is required on ARM. (The
> current xen-command-line document does not actually reflect the current
> behavior of dom0_mem on ARM correctly.)
> 
> Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> ---
> Changes in v3:
> - update docs
> ---
>  docs/misc/xen-command-line.markdown |  8 +++++++-
>  xen/arch/arm/domain_build.c         | 22 +++++++++++++++++-----
>  2 files changed, 24 insertions(+), 6 deletions(-)
> 
> diff --git a/docs/misc/xen-command-line.markdown 
> b/docs/misc/xen-command-line.markdown
> index a11fdf9..c0106fb 100644
> --- a/docs/misc/xen-command-line.markdown
> +++ b/docs/misc/xen-command-line.markdown
> @@ -603,7 +603,13 @@ For example, with `dom0_max_vcpus=4-8`:
>  >      8    |  8
>  >     10    |  8
>  
> -### dom0\_mem
> +### dom0\_mem (ARM)
> +> `= <size>`
> +
> +Set the amount of memory for the initial domain (dom0). It must be
> +greater than zero. This parameter is required.
> +
> +### dom0\_mem (x86)
>  > `= List of ( min:<size> | max:<size> | <size> )`
>  
>  Set the amount of memory for the initial domain (dom0). If a size is
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index c97a1f5..db7471f 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -1,4 +1,5 @@
>  #include <xen/config.h>
> +#include <xen/delay.h>
>  #include <xen/init.h>
>  #include <xen/compile.h>
>  #include <xen/lib.h>
> @@ -31,14 +32,11 @@ integer_param("dom0_max_vcpus", opt_dom0_max_vcpus);
>  
>  int dom0_11_mapping = 1;
>  
> -#define DOM0_MEM_DEFAULT 0x8000000 /* 128 MiB */
> -static u64 __initdata dom0_mem = DOM0_MEM_DEFAULT;
> +static u64 __initdata dom0_mem;
>  
>  static void __init parse_dom0_mem(const char *s)
>  {
>      dom0_mem = parse_size_and_unit(s, &s);
> -    if ( dom0_mem == 0 )
> -        dom0_mem = DOM0_MEM_DEFAULT;
>  }
>  custom_param("dom0_mem", parse_dom0_mem);
>  
> @@ -2125,7 +2123,21 @@ int construct_dom0(struct domain *d)
>      BUG_ON(d->vcpu[0] == NULL);
>      BUG_ON(v->is_initialised);
>  
> -    printk("*** LOADING DOMAIN 0 ***\n");
> +    if ( dom0_mem > 0 )
> +        printk("*** LOADING DOMAIN 0 ***\n");
> +    else
> +    {
> +        int i;
> +        printk("*** PLEASE SPECIFY dom0_mem PARAMETER - USING 512M FOR NOW 
> ***\n");
> +        for (i = 0; i < 3; i++)
> +        {
> +            printk("%d...", i+1);
> +            mdelay(1000);

There is infrastructure in Xen to print warning messages, so that we
don't add delays unnecessarily.

See warning.h:warning_add.

Wei.

> +        }
> +        printk("\n");
> +        dom0_mem = MB(512);
> +    }
> +
>  
>      iommu_hwdom_init(d);
>  
> -- 
> 1.9.1
> 
> 
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> https://lists.xen.org/xen-devel

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