Re: [Xen-devel] [PATCH] x86: fix nested HVM initialization

[Christoph Egger <Christoph.Egger@xxxxxxx>]

On 05/24/12 14:14, Jan Beulich wrote:

> - no need for calling nestedhvm_setup() explicitly (can be a normal
>   init-call, and can be __init)
> - calling _xmalloc() for multi-page, page-aligned memory regions is
>   inefficient - use alloc_xenheap_pages() instead
> - albeit an allocation error is unlikely here, add error handling
>   nevertheless (and have nestedhvm_vcpu_initialise() bail if an error
>   occurred during setup)
> - nestedhvm_enabled() must no access d->arch.hvm_domain without first
>   checking that 'd' actually represents a HVM domain
> 
> Signed-off-by: Jan Beulich <JBeulich@xxxxxxxx>


Looks ok to me. How did you test it?

Christoph

> 
> --- a/xen/arch/x86/hvm/nestedhvm.c
> +++ b/xen/arch/x86/hvm/nestedhvm.c
> @@ -25,16 +25,14 @@
>  #include <asm/event.h>  /* for local_event_delivery_(en|dis)able */
>  #include <asm/paging.h> /* for paging_mode_hap() */
>  
> +static unsigned long *shadow_io_bitmap[3];
> +
>  /* Nested HVM on/off per domain */
>  bool_t
>  nestedhvm_enabled(struct domain *d)
>  {
> -    bool_t enabled;
> -
> -    enabled = !!(d->arch.hvm_domain.params[HVM_PARAM_NESTEDHVM]);
> -    BUG_ON(enabled && !is_hvm_domain(d));
> -    
> -    return enabled;
> +    return is_hvm_domain(d) &&
> +           d->arch.hvm_domain.params[HVM_PARAM_NESTEDHVM];
>  }
>  
>  /* Nested VCPU */
> @@ -76,6 +74,9 @@ nestedhvm_vcpu_initialise(struct vcpu *v
>  {
>      int rc = -EOPNOTSUPP;
>  
> +    if ( !shadow_io_bitmap[0] )
> +        return -ENOMEM;
> +
>      if ( !hvm_funcs.nhvm_vcpu_initialise ||
>           ((rc = hvm_funcs.nhvm_vcpu_initialise(v)) != 0) )
>           return rc;
> @@ -147,15 +148,15 @@ nestedhvm_is_n2(struct vcpu *v)
>   * iomap[2]      set        set
>   */
>  
> -static unsigned long *shadow_io_bitmap[3];
> -
> -void
> +static int __init
>  nestedhvm_setup(void)
>  {
>      /* Same format and size as hvm_io_bitmap (Intel needs only 2 pages). */
> -    unsigned int sz = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
> -        ? 2*PAGE_SIZE : 3*PAGE_SIZE;
> -    unsigned int i;
> +    unsigned int nr = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) ? 2 : 3;
> +    unsigned int i, order = get_order_from_pages(nr);
> +
> +    if ( !hvm_funcs.name )
> +        return 0;
>  
>      /* shadow_io_bitmaps can't be declared static because
>       *   they must fulfill hw requirements (page aligned section)
> @@ -169,13 +170,25 @@ nestedhvm_setup(void)
>  
>      for ( i = 0; i < ARRAY_SIZE(shadow_io_bitmap); i++ )
>      {
> -        shadow_io_bitmap[i] = _xmalloc(sz, PAGE_SIZE);
> -        memset(shadow_io_bitmap[i], ~0U, sz);
> +        shadow_io_bitmap[i] = alloc_xenheap_pages(order, 0);
> +        if ( !shadow_io_bitmap[i] )
> +        {
> +            while ( i-- )
> +            {
> +                free_xenheap_pages(shadow_io_bitmap[i], order);
> +                shadow_io_bitmap[i] = NULL;
> +            }
> +            return -ENOMEM;
> +        }
> +        memset(shadow_io_bitmap[i], ~0U, nr << PAGE_SHIFT);
>      }
>  
>      __clear_bit(0x80, shadow_io_bitmap[0]);
>      __clear_bit(0xed, shadow_io_bitmap[1]);
> +
> +    return 0;
>  }
> +__initcall(nestedhvm_setup);
>  
>  unsigned long *
>  nestedhvm_vcpu_iomap_get(bool_t port_80, bool_t port_ed)
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1312,8 +1312,6 @@ void __init __start_xen(unsigned long mb
>      if ( opt_watchdog ) 
>          watchdog_setup();
>  
> -    nestedhvm_setup();
> -    
>      if ( !tboot_protect_mem_regions() )
>          panic("Could not protect TXT memory regions\n");
>  
> --- a/xen/include/asm-x86/setup.h
> +++ b/xen/include/asm-x86/setup.h
> @@ -21,7 +21,6 @@ void set_nr_cpu_ids(unsigned int max_cpu
>  void numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn);
>  void arch_init_memory(void);
>  void subarch_init_memory(void);
> -void nestedhvm_setup(void);
>  
>  void init_IRQ(void);
>  void vesa_init(void);
> 
> 
> 



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