1.1 --- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/ioport.c	Thu Aug 04 09:00:16 2005 +0000
     1.2 +++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/ioport.c	Thu Aug 04 13:13:02 2005 +0000
     1.3 @@ -113,16 +113,12 @@ asmlinkage long sys_iopl(unsigned int ne
     1.4  	if ((new_io_pl > old_io_pl) && !capable(CAP_SYS_RAWIO))
     1.5  		return -EPERM;
     1.6  
     1.7 -	/* Maintain OS privileges even if user attempts to relinquish them. */
     1.8 -	if (new_io_pl == 0)
     1.9 -		new_io_pl = 1;
    1.10 -
    1.11  	/* Change our version of the privilege levels. */
    1.12  	current->thread.io_pl = new_io_pl;
    1.13  
    1.14  	/* Force the change at ring 0. */
    1.15  	op.cmd             = PHYSDEVOP_SET_IOPL;
    1.16 -	op.u.set_iopl.iopl = new_io_pl;
    1.17 +	op.u.set_iopl.iopl = (new_io_pl == 0) ? 1 : new_io_pl;
    1.18  	HYPERVISOR_physdev_op(&op);
    1.19  
    1.20  	return 0;

     2.1 --- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/process.c	Thu Aug 04 09:00:16 2005 +0000
     2.2 +++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/process.c	Thu Aug 04 13:13:02 2005 +0000
     2.3 @@ -539,7 +539,7 @@ struct task_struct fastcall * __switch_t
     2.4  
     2.5  	if (unlikely(prev->io_pl != next->io_pl)) {
     2.6  		iopl_op.cmd             = PHYSDEVOP_SET_IOPL;
     2.7 -		iopl_op.u.set_iopl.iopl = next->io_pl;
     2.8 +		iopl_op.u.set_iopl.iopl = (next->io_pl == 0) ? 1 : next->io_pl;
     2.9  		mcl->op      = __HYPERVISOR_physdev_op;
    2.10  		mcl->args[0] = (unsigned long)&iopl_op;
    2.11  		mcl++;

     3.1 --- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/setup.c	Thu Aug 04 09:00:16 2005 +0000
     3.2 +++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/setup.c	Thu Aug 04 13:13:02 2005 +0000
     3.3 @@ -1636,7 +1636,7 @@ void __init setup_arch(char **cmdline_p)
     3.4  		efi_map_memmap();
     3.5  
     3.6  	op.cmd             = PHYSDEVOP_SET_IOPL;
     3.7 -	op.u.set_iopl.iopl = current->thread.io_pl = 1;
     3.8 +	op.u.set_iopl.iopl = 1;
     3.9  	HYPERVISOR_physdev_op(&op);
    3.10  
    3.11  #ifdef CONFIG_ACPI_BOOT

     4.1 --- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c	Thu Aug 04 09:00:16 2005 +0000
     4.2 +++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/smpboot.c	Thu Aug 04 13:13:02 2005 +0000
     4.3 @@ -880,7 +880,8 @@ static int __init do_boot_cpu(int apicid
     4.4  	ctxt.user_regs.cs = __KERNEL_CS;
     4.5  	ctxt.user_regs.eip = start_eip;
     4.6  	ctxt.user_regs.esp = idle->thread.esp;
     4.7 -	ctxt.user_regs.eflags = (1<<9) | (1<<2) | (idle->thread.io_pl<<12);
     4.8 +#define X86_EFLAGS_IOPL_RING1 0x1000
     4.9 +	ctxt.user_regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_IOPL_RING1;
    4.10  
    4.11  	/* FPU is set up to default initial state. */
    4.12  	memset(&ctxt.fpu_ctxt, 0, sizeof(ctxt.fpu_ctxt));

     5.1 --- a/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/ioport.c	Thu Aug 04 09:00:16 2005 +0000
     5.2 +++ b/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/ioport.c	Thu Aug 04 13:13:02 2005 +0000
     5.3 @@ -30,7 +30,6 @@ asmlinkage long sys_iopl(unsigned int ne
     5.4          unsigned int old_io_pl = current->thread.io_pl;
     5.5          physdev_op_t op;
     5.6  
     5.7 -
     5.8  	if (new_io_pl > 3)
     5.9  		return -EINVAL;
    5.10  
    5.11 @@ -38,16 +37,12 @@ asmlinkage long sys_iopl(unsigned int ne
    5.12  	if ((new_io_pl > old_io_pl) && !capable(CAP_SYS_RAWIO))
    5.13  		return -EPERM;
    5.14  
    5.15 -	/* Maintain OS privileges even if user attempts to relinquish them. */
    5.16 -	if (new_io_pl == 0)
    5.17 -		new_io_pl = 1;
    5.18 -
    5.19  	/* Change our version of the privilege levels. */
    5.20  	current->thread.io_pl = new_io_pl;
    5.21  
    5.22  	/* Force the change at ring 0. */
    5.23  	op.cmd             = PHYSDEVOP_SET_IOPL;
    5.24 -	op.u.set_iopl.iopl = new_io_pl;
    5.25 +	op.u.set_iopl.iopl = (new_io_pl == 0) ? 1 : new_io_pl;
    5.26  	HYPERVISOR_physdev_op(&op);
    5.27  
    5.28  	return 0;

     6.1 --- a/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/process.c	Thu Aug 04 09:00:16 2005 +0000
     6.2 +++ b/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/process.c	Thu Aug 04 13:13:02 2005 +0000
     6.3 @@ -465,7 +465,7 @@ struct task_struct *__switch_to(struct t
     6.4  
     6.5  	if (unlikely(prev->io_pl != next->io_pl)) {
     6.6  		iopl_op.cmd             = PHYSDEVOP_SET_IOPL;
     6.7 -		iopl_op.u.set_iopl.iopl = next->io_pl;
     6.8 +		iopl_op.u.set_iopl.iopl = (next->io_pl == 0) ? 1 : next->io_pl;
     6.9  		mcl->op      = __HYPERVISOR_physdev_op;
    6.10  		mcl->args[0] = (unsigned long)&iopl_op;
    6.11  		mcl++;

     7.1 --- a/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/setup.c	Thu Aug 04 09:00:16 2005 +0000
     7.2 +++ b/linux-2.6-xen-sparse/arch/xen/x86_64/kernel/setup.c	Thu Aug 04 13:13:02 2005 +0000
     7.3 @@ -824,7 +824,7 @@ void __init setup_arch(char **cmdline_p)
     7.4  #endif
     7.5  
     7.6  	op.cmd             = PHYSDEVOP_SET_IOPL;
     7.7 -	op.u.set_iopl.iopl = current->thread.io_pl = 1;
     7.8 +	op.u.set_iopl.iopl = 1;
     7.9  	HYPERVISOR_physdev_op(&op);
    7.10  
    7.11  	if (xen_start_info.flags & SIF_INITDOMAIN) {