Re: [Xen-devel] [PATCH] x86: remove shadow dom0 command line option

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Mar 24, 2017 at 05:51:41PM +0000, Wei Liu wrote:
> It has been broken for years and couldn't possibly be configured after
> 4045953.
> 
> Remove code and documentation.
> 
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> ---
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> ---
>  docs/misc/xen-command-line.markdown | 13 +------------
>  xen/arch/x86/dom0_build.c           | 10 +---------
>  xen/arch/x86/pv/dom0_build.c        |  5 -----
>  xen/arch/x86/setup.c                |  3 +--
>  4 files changed, 3 insertions(+), 28 deletions(-)
> 
> diff --git a/docs/misc/xen-command-line.markdown 
> b/docs/misc/xen-command-line.markdown
> index bdbdb8a53b..f86b1bb7d2 100644
> --- a/docs/misc/xen-command-line.markdown
> +++ b/docs/misc/xen-command-line.markdown
> @@ -652,11 +652,6 @@ restrictions set up here. Note that the values to be 
> specified here are
>  ACPI PXM ones, not Xen internal node numbers. `relaxed` sets up vCPU
>  affinities to prefer but be not limited to the specified node(s).
>  
> -### dom0\_shadow
> -> `= <boolean>`
> -
> -This option is deprecated, please use `dom0=shadow` instead.
> -
>  ### dom0\_vcpus\_pin
>  > `= <boolean>`
>  
> @@ -665,7 +660,7 @@ This option is deprecated, please use `dom0=shadow` 
> instead.
>  Pin dom0 vcpus to their respective pcpus
>  
>  ### dom0
> -> `= List of [ pvh | shadow ]`
> +> `= List of [ pvh ]`

The shadow option here needs to be kept, in case someone wants to create a
PVHv2 Dom0 with shadow instead of hap.

>  
>  > Sub-options:
>  
> @@ -675,12 +670,6 @@ Pin dom0 vcpus to their respective pcpus
>  
>  Flag that makes a dom0 boot in PVHv2 mode.
>  
> -> `shadow`
> -
> -> Default: `false`
> -
> -Flag that makes a dom0 use shadow paging.

I would add "Only supported in conjunction with the pvh option".

> -
>  ### dtuart (ARM)
>  > `= path [:options]`
>  
> diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
> index 20221b5e32..c6476023d1 100644
> --- a/xen/arch/x86/dom0_build.c
> +++ b/xen/arch/x86/dom0_build.c
> @@ -172,10 +172,6 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
>                             cpumask_last(&dom0_cpus) /* so it wraps around to 
> first pcpu */);
>  }
>  
> -#ifdef CONFIG_SHADOW_PAGING
> -bool __initdata opt_dom0_shadow;
> -boolean_param("dom0_shadow", opt_dom0_shadow);
> -#endif
>  bool __initdata dom0_pvh;
>  
>  /*
> @@ -196,10 +192,6 @@ static void __init parse_dom0_param(char *s)
>  
>          if ( !strcmp(s, "pvh") )
>              dom0_pvh = true;
> -#ifdef CONFIG_SHADOW_PAGING
> -        else if ( !strcmp(s, "shadow") )
> -            opt_dom0_shadow = true;
> -#endif
>  
>          s = ss + 1;
>      } while ( ss );

if ( opt_dom0_shadow && !dom0_pvh )
    panic("Combination of options not supported, shadow requires pvh");

Or something similar.

> @@ -253,7 +245,7 @@ unsigned long __init dom0_compute_nr_pages(
>      }
>  
>      need_paging = is_hvm_domain(d) ? !iommu_hap_pt_share || 
> !paging_mode_hap(d)
> -                                   : opt_dom0_shadow;
> +                                   : 0;
>      for ( ; ; need_paging = 0 )
>      {
>          nr_pages = dom0_nrpages;
> diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
> index 65cd2c5019..18c19a256f 100644
> --- a/xen/arch/x86/pv/dom0_build.c
> +++ b/xen/arch/x86/pv/dom0_build.c
> @@ -870,11 +870,6 @@ int __init dom0_construct_pv(struct domain *d,
>      regs->rsi = vstartinfo_start;
>      regs->eflags = X86_EFLAGS_IF;
>  
> -#ifdef CONFIG_SHADOW_PAGING
> -    if ( opt_dom0_shadow && paging_enable(d, PG_SH_enable) == 0 )
> -        paging_update_paging_modes(v);
> -#endif
> -
>      if ( test_bit(XENFEAT_supervisor_mode_kernel, parms.f_required) )
>          panic("Dom0 requires supervisor-mode execution");
>  
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index be10a4f32e..55655005f1 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1561,8 +1561,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
>      if ( dom0_pvh )
>      {
>          domcr_flags |= DOMCRF_hvm |
> -                       ((hvm_funcs.hap_supported && !opt_dom0_shadow) ?
> -                         DOMCRF_hap : 0);
> +                       (hvm_funcs.hap_supported ? DOMCRF_hap : 0);

The chunk above needs to stay.

Roger.

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