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Date: Fri, 13 Dec 2013 11:34:54 +0000
From: David Vrabel <david.vrabel@citrix.com>
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To: Konrad Rzeszutek Wilk <konrad@kernel.org>
CC: <xen-devel@lists.xenproject.org>, <linux-kernel@vger.kernel.org>,
        <george.dunlap@eu.citrix.com>, <ian.jackson@eu.citrix.com>,
        <mukesh.rathor@oracle.com>, <tim@xen.org>, <jbeulich@suse.com>,
        <boris.ostrovsky@oracle.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH V10 14/14] xen/pvh: vcpu info placement, load CS selector,
 and remove debug printk.
References: <1386900621-27528-1-git-send-email-konrad.wilk@oracle.com> <1386900621-27528-15-git-send-email-konrad.wilk@oracle.com>
In-Reply-To: <1386900621-27528-15-git-send-email-konrad.wilk@oracle.com>
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On 13/12/13 02:10, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@oracle.com>
> 
> This patch addresses 3 things:
>    - Resolve vcpu info placement fixme.
>    - Load CS selector for PVH after switching to new gdt.
>    - Remove printk in case of failure to map pnfs in p2m. This because qemu
>      has lot of expected failures when mapping HVM pages.
[...]
> @@ -1423,7 +1425,20 @@ static void __init xen_setup_stackprotector(void)
>  {
>  	/* PVH TBD/FIXME: investigate setup_stack_canary_segment */
>  	if (xen_feature(XENFEAT_auto_translated_physmap)) {
> +		unsigned long dummy;
> +
>  		switch_to_new_gdt(0);
> +#ifdef CONFIG_X86_64
> +		asm volatile ("pushq %0\n"
> +			      "leaq 1f(%%rip),%0\n"
> +			      "pushq %0\n"
> +			      "lretq\n"
> +			      "1:\n"
> +			      : "=&r" (dummy) : "0" (__KERNEL_CS));

Why does CS need to be reloaded here?

David