Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933494AbbGGTzF (ORCPT ); Tue, 7 Jul 2015 15:55:05 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:35353 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933448AbbGGTyg (ORCPT ); Tue, 7 Jul 2015 15:54:36 -0400 Date: Tue, 7 Jul 2015 15:54:24 -0400 From: Konrad Rzeszutek Wilk To: Boris Ostrovsky Cc: david.vrabel@citrix.com, roger.pau@citrix.com, elena.ufimtseva@oracle.com, stefano.stabellini@eu.citrix.com, tim@xen.org, jbeulich@suse.com, andrew.cooper3@citrix.com, ian.campbell@citrix.com, wei.liu2@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/6] xen/x86/pvh: Set up descriptors for 32-bit PVH guests Message-ID: <20150707195424.GD6372@l.oracle.com> References: <1436240065-10813-1-git-send-email-boris.ostrovsky@oracle.com> <1436240065-10813-5-git-send-email-boris.ostrovsky@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1436240065-10813-5-git-send-email-boris.ostrovsky@oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2240 Lines: 66 On Mon, Jul 06, 2015 at 11:34:23PM -0400, Boris Ostrovsky wrote: > Signed-off-by: Boris Ostrovsky > --- > arch/x86/xen/enlighten.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index 0b95c9b..7953e68 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -1362,12 +1362,12 @@ static void __init xen_boot_params_init_edd(void) > static void __ref xen_setup_gdt(int cpu) > { > if (xen_feature(XENFEAT_auto_translated_physmap)) { > -#ifdef CONFIG_X86_64 > unsigned long dummy; > > - load_percpu_segment(cpu); /* We need to access per-cpu area */ > + setup_stack_canary_segment(cpu); > switch_to_new_gdt(cpu); /* GDT and GS set */ > > +#ifdef CONFIG_X86_64 > /* We are switching of the Xen provided GDT to our HVM mode > * GDT. The new GDT has __KERNEL_CS with CS.L = 1 > * and we are jumping to reload it. > @@ -1392,8 +1392,16 @@ static void __ref xen_setup_gdt(int cpu) > loadsegment(ds, 0); > loadsegment(fs, 0); > #else > - /* PVH: TODO Implement. */ > - BUG(); > + asm volatile ("ljmp %1,$1f\n" > + "1:\n" > + "movl %2,%0\n" > + "movl %0,%%ss\n" > + "movl %3,%0\n" > + "movl %0,%%ds\n" > + "movl %0,%%es\n" > + : "=&r" (dummy) > + : "i" (__KERNEL_CS), "i" (__KERNEL_DS), > + "i" (__USER_DS)); > #endif Which comes out to: ljmp $96,$1f #[KERNEL_CS] 1: movl $104,%eax #, dummy #[KERNEL_DS] movl %eax,%ss # dummy movl $123,%eax #, dummy #[USER_DS] movl %eax,%ds # dummy movl %eax,%es # dummy And that looks right Reviewed-by: Konrad Rzeszutek Wilk > return; /* PVH does not need any PV GDT ops. */ > } > -- > 1.8.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/