From: Andi Kleen <ak@suse.de>
To: virtualization@lists.osdl.org
Subject: Re: [RFC PATCH 11/35] Add support for Xen to entry.S.
Date: Tue, 9 May 2006 18:51:37 +0200
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Cc: Chris Wright <chrisw@sous-sol.org>, linux-kernel@vger.kernel.org,
       xen-devel@lists.xensource.com, Ian Pratt <ian.pratt@xensource.com>
References: <20060509084945.373541000@sous-sol.org> <20060509085152.524462000@sous-sol.org>
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On Tuesday 09 May 2006 09:00, Chris Wright wrote:

> +#define sizeof_vcpu_shift		6

This should be generated in asm-offsets.c

> +
> +#ifdef CONFIG_SMP
> +#define GET_VCPU_INFO		movl TI_cpu(%ebp),%esi			; \
> +				shl  $sizeof_vcpu_shift,%esi		; \
> +				addl HYPERVISOR_shared_info,%esi

I think you need some comments on the register usage in the macros.
Otherwise people hacking on it later will go crazy.

>  restore_all:
> +#ifndef CONFIG_XEN
>  	movl EFLAGS(%esp), %eax		# mix EFLAGS, SS and CS
>  	# Warning: OLDSS(%esp) contains the wrong/random values if we
>  	# are returning to the kernel.
> @@ -258,12 +289,32 @@ restore_all:
>  	cmpl $((4 << 8) | 3), %eax
>  	je ldt_ss			# returning to user-space with LDT SS
>  restore_nocheck:
> +#else

Needs comment

> +restore_nocheck:
> +	movl EFLAGS(%esp), %eax		# mix EFLAGS and CS
> +	movb CS(%esp), %al
> +	andl $(VM_MASK | 3), %eax
> +	cmpl $3, %eax
> +	jne hypervisor_iret
> +	ENABLE_INTERRUPTS
>

-Andi
-
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