Re: [Xen-devel] [v2 05/16] xen/arm: guest_copy: Extend the prototype to pass the vCPU

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 12 Dec 2017, Julien Grall wrote:
> Currently, guest_copy assumes the copy will only be done for the current
> vCPU. copy_guest is meant to be vCPU agnostic, so extend the prototype
> to pass the vCPU.
> 
> At the same time, encapsulate the vCPU in an union to allow extension
> for copying from a guest domain (ipa case) in the future.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v2:
>         - Encapsulate the vCPU in an union.
>         - Rework the commit message
> ---
>  xen/arch/arm/guestcopy.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/xen/arch/arm/guestcopy.c b/xen/arch/arm/guestcopy.c
> index ff7d15380f..7e92e27beb 100644
> --- a/xen/arch/arm/guestcopy.c
> +++ b/xen/arch/arm/guestcopy.c
> @@ -9,8 +9,18 @@
>  #define COPY_from_guest     (0U << 1)
>  #define COPY_to_guest       (1U << 1)
>  
> +typedef union
> +{
> +    struct
> +    {
> +        struct vcpu *v;
> +    } gva;
> +} copy_info_t;
> +
> +#define GVA_INFO(vcpu) ((copy_info_t) { .gva = { vcpu } })
> +
>  static unsigned long copy_guest(void *buf, uint64_t addr, unsigned int len,
> -                                unsigned int flags)
> +                                copy_info_t info, unsigned int flags)
>  {
>      /* XXX needs to handle faults */
>      unsigned offset = addr & ~PAGE_MASK;
> @@ -23,7 +33,7 @@ static unsigned long copy_guest(void *buf, uint64_t addr, 
> unsigned int len,
>          unsigned size = min(len, (unsigned)PAGE_SIZE - offset);
>          struct page_info *page;
>  
> -        page = get_page_from_gva(current, addr,
> +        page = get_page_from_gva(info.gva.v, addr,
>                                   (flags & COPY_to_guest) ? GV2M_WRITE : 
> GV2M_READ);
>          if ( page == NULL )
>              return len;
> @@ -64,24 +74,27 @@ static unsigned long copy_guest(void *buf, uint64_t addr, 
> unsigned int len,
>  
>  unsigned long raw_copy_to_guest(void *to, const void *from, unsigned len)
>  {
> -    return copy_guest((void *)from, (vaddr_t)to, len, COPY_to_guest);
> +    return copy_guest((void *)from, (vaddr_t)to, len,
> +                      GVA_INFO(current), COPY_to_guest);
>  }
>  
>  unsigned long raw_copy_to_guest_flush_dcache(void *to, const void *from,
>                                               unsigned len)
>  {
> -    return copy_guest((void *)from, (vaddr_t)to, len,
> +    return copy_guest((void *)from, (vaddr_t)to, len, GVA_INFO(current),
>                        COPY_to_guest | COPY_flush_dcache);
>  }
>  
>  unsigned long raw_clear_guest(void *to, unsigned len)
>  {
> -    return copy_guest(NULL, (vaddr_t)to, len, COPY_to_guest);
> +    return copy_guest(NULL, (vaddr_t)to, len, GVA_INFO(current),
> +                      COPY_to_guest);
>  }
>  
>  unsigned long raw_copy_from_guest(void *to, const void __user *from, 
> unsigned len)
>  {
> -    return copy_guest(to, (vaddr_t)from, len, COPY_from_guest);
> +    return copy_guest(to, (vaddr_t)from, len, GVA_INFO(current),
> +                      COPY_from_guest);
>  }
>  
>  /*
> -- 
> 2.11.0
> 

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