RE: [Xen-devel] [PATCH] vmx-copy_from_guest.patch

["Ling, Xiaofeng" <xiaofeng.ling@xxxxxxxxx>]

seems current vmx_copy can not deal with copy over page boundary?
so remove inst_copy_from_guest will cause problem.

Leendert van Doorn <> wrote:
> Reducing LOC (always a good thing) by eliminating duplicated
> functionality. 
> vmx_platform.c/inst_copy_from_guest() now uses vmx_copy. Also shored
> up vmx_copy to handle copies when paging is enabled and improved its
> error handling.  
> 
> Signed-Off-By: Leendert van Doorn <leendert@xxxxxxxxxxxxxx>
> 
> diff -r 23d8580d56b0 xen/arch/x86/vmx.c
> --- a/xen/arch/x86/vmx.c      Fri Sep  2 18:23:57 2005
> +++ b/xen/arch/x86/vmx.c      Mon Sep  5 13:43:59 2005
> @@ -729,7 +735,7 @@
>  int
>  vmx_copy(void *buf, unsigned long laddr, int size, int dir)  {
> -    unsigned long mfn;
> +    unsigned long gpa, mfn;
>      char *addr;
>      int count;
> 
> @@ -738,8 +744,14 @@
>       if (count > size)
>           count = size;
> 
> -     mfn = get_mfn_from_pfn(laddr >> PAGE_SHIFT);
> -     /* XXX check whether laddr is valid */
> +     if (vmx_paging_enabled(current)) {
> +             gpa = gva_to_gpa(laddr);
> +             mfn = get_mfn_from_pfn(gpa >> PAGE_SHIFT);
> +     } else
> +             mfn = get_mfn_from_pfn(laddr >> PAGE_SHIFT);
> +     if (mfn == INVALID_MFN)
> +             return 0;
> +
>       addr = (char *)map_domain_page(mfn) + (laddr & ~PAGE_MASK);
> 
>       if (dir == VMX_COPY_IN)
> diff -r 23d8580d56b0 xen/arch/x86/vmx_platform.c
> --- a/xen/arch/x86/vmx_platform.c     Fri Sep  2 18:23:57 2005
> +++ b/xen/arch/x86/vmx_platform.c     Mon Sep  5 13:43:59 2005
> @@ -583,49 +583,13 @@
>      }
>  }
> 
> -/* XXX use vmx_copy instead */
>  int inst_copy_from_guest(unsigned char *buf, unsigned long
> guest_eip, int inst_len)  { 
> -    unsigned long gpa;
> -    unsigned long mfn;
> -    unsigned char *inst_start;
> -    int remaining = 0;
> -
> -    if ( (inst_len > MAX_INST_LEN) || (inst_len <= 0) )
> +    if (inst_len > MAX_INST_LEN || inst_len <= 0)
>          return 0;
> -
> -    if ( vmx_paging_enabled(current) )
> -    {
> -        gpa = gva_to_gpa(guest_eip);
> -        mfn = get_mfn_from_pfn(gpa >> PAGE_SHIFT);
> -
> -        /* Does this cross a page boundary ? */
> -        if ( (guest_eip & PAGE_MASK) != ((guest_eip + inst_len) &
> PAGE_MASK) ) 
> -        {
> -            remaining = (guest_eip + inst_len) & ~PAGE_MASK;
> -            inst_len -= remaining;
> -        }
> -    }
> -    else
> -    {
> -        mfn = get_mfn_from_pfn(guest_eip >> PAGE_SHIFT);
> -    }
> -
> -    inst_start = map_domain_page(mfn);
> -    memcpy((char *)buf, inst_start + (guest_eip & ~PAGE_MASK),
> inst_len); 
> -    unmap_domain_page(inst_start);
> -
> -    if ( remaining )
> -    {
> -        gpa = gva_to_gpa(guest_eip+inst_len+remaining);
> -        mfn = get_mfn_from_pfn(gpa >> PAGE_SHIFT);
> -
> -        inst_start = map_domain_page(mfn);
> -        memcpy((char *)buf+inst_len, inst_start, remaining);
> -        unmap_domain_page(inst_start);
> -    }
> -
> -    return inst_len+remaining;
> +    if (!vmx_copy(buf, guest_eip, inst_len, VMX_COPY_IN))
> +        return 0;
> +    return inst_len;
>  }
> 
>  void send_mmio_req(unsigned char type, unsigned long gpa,
> 
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