Re: [Xen-devel] [PATCH v2] Fix the mistake for #DB and #OF exception

["Dong, Eddie" <eddie.dong@xxxxxxxxx>]

Xudong:
        VM_ENTRY_INSTRUCTION_LEN is hard to detect due to the prefix 
instruction. We may rely on the caller to handle...
Thx, Eddie

> -----Original Message-----
> From: Hao, Xudong
> Sent: Saturday, May 12, 2012 5:13 PM
> To: Jan Beulich (JBeulich@xxxxxxxx); Keir Fraser (keir.xen@xxxxxxxxx)
> Cc: Aravindh Puthiyaparambil; Dong, Eddie; Zhang, Xiantao; Nakajima, Jun;
> xen-devel (xen-devel@xxxxxxxxxxxxx)
> Subject: [PATCH v2] Fix the mistake for #DB and #OF exception
> 
> Fix the mistake for debug exception(#DB; generated by INT1), overflow
> exception(#OF; generated by INTO) and int n instruction emulation.
> 
> #DB should use hardware exception(except #DB generated by opcode 0xf1),
> #OF should use software exception, which int n instruction should use
> software interrupt.
> 
> Signed-off-by: Eddie Dong<eddie.dong@xxxxxxxxx>
> Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
> 
> diff -r cd4dd23a831d xen/arch/x86/hvm/vmx/vmx.c
> --- a/xen/arch/x86/hvm/vmx/vmx.c      Fri May 11 18:59:07 2012 +0100
> +++ b/xen/arch/x86/hvm/vmx/vmx.c      Mon May 13 01:01:24 2013 +0800
> @@ -1350,6 +1350,14 @@ static void __vmx_inject_exception(int t
>          curr->arch.hvm_vmx.vmx_emulate = 1;
>  }
> 
> +/*
> + * Generate the virtual event to guest.
> + * NOTE:
> + *    This is for processor execution generated exceptions,
> + * and INT 3(CC), INTO (CE) instruction emulation. INT3 and
> + * INT0 use software exception, and INT n should use
> + * software interrupt.
> + */
>  void vmx_inject_hw_exception(int trap, int error_code)
>  {
>      unsigned long intr_info;
> @@ -1365,7 +1373,6 @@ void vmx_inject_hw_exception(int trap, i
>      switch ( trap )
>      {
>      case TRAP_debug:
> -        type = X86_EVENTTYPE_SW_EXCEPTION;
>          if ( guest_cpu_user_regs()->eflags & X86_EFLAGS_TF )
>          {
>              __restore_debug_registers(curr);
> @@ -1387,10 +1394,15 @@ void vmx_inject_hw_exception(int trap, i
>          __vmwrite(VM_ENTRY_INSTRUCTION_LEN, 1); /* int3 */
>          break;
> 
> +    case TRAP_overflow:
> +        type = X86_EVENTTYPE_SW_EXCEPTION;
> +        __vmwrite(VM_ENTRY_INSTRUCTION_LEN, 1); /* into */
> +        break;
> +
>      default:
>          if ( trap > TRAP_last_reserved )
>          {
> -            type = X86_EVENTTYPE_SW_EXCEPTION;
> +            type = X86_EVENTTYPE_SW_INTERRUPT;
>              __vmwrite(VM_ENTRY_INSTRUCTION_LEN, 2); /* int imm8
> */
>          }
>          break;

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel