This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-devel] Re: [RFC PATCH 16/33] Add support for Xen to entry.S.

To: Chris Wright <chrisw@xxxxxxxxxxxx>
Subject: [Xen-devel] Re: [RFC PATCH 16/33] Add support for Xen to entry.S.
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Tue, 18 Jul 2006 16:03:13 -0700
Cc: Andrew Morton <akpm@xxxxxxxx>, Zachary Amsden <zach@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>, Ian Pratt <ian.pratt@xxxxxxxxxxxxx>, Rusty Russell <rusty@xxxxxxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, Andi Kleen <ak@xxxxxxx>, virtualization@xxxxxxxxxxxxxx, Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
Delivery-date: Thu, 20 Jul 2006 05:29:53 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20060718204333.GD2654@xxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <20060718091807.467468000@xxxxxxxxxxxx> <20060718091952.505770000@xxxxxxxxxxxx> <1153250220.5467.38.camel@xxxxxxxxxxxxxxxxxxxxx> <20060718204333.GD2654@xxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (X11/20060613)
Chris Wright wrote:
* Rusty Russell (rusty@xxxxxxxxxxxxxxx) wrote:
On Tue, 2006-07-18 at 00:00 -0700, Chris Wright wrote:
plain text document attachment (i386-entry.S)
- change cli/sti
- change test for user mode return to work for kernel mode in ring1
- check hypervisor saved event mask on return from exception
- add entry points for the hypervisor upcall handlers
- avoid math emulation check when running on Xen
- add nmi handler for running on Xen

Signed-off-by: Ian Pratt <ian.pratt@xxxxxxxxxxxxx>
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>

 arch/i386/kernel/asm-offsets.c |   26 +++++++
 arch/i386/kernel/entry.S       |  141 ++++++++++++++++++++++++++++++++++++-----
 arch/i386/mach-xen/setup-xen.c |   19 +++++
 drivers/xen/core/features.c    |    2
 4 files changed, 169 insertions(+), 19 deletions(-)

diff -r 5cca1805b8a7 arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S  Tue Jul 18 02:20:39 2006 -0400
+++ b/arch/i386/kernel/entry.S  Tue Jul 18 02:22:56 2006 -0400
@@ -76,8 +76,39 @@ NT_MASK              = 0x00004000
 NT_MASK                = 0x00004000
 VM_MASK                = 0x00020000
+#ifndef CONFIG_XEN
+#define DISABLE_INTERRUPTS     cli
+#define ENABLE_INTERRUPTS      sti
+#include <xen/interface/xen.h>
+EVENT_MASK     = 0x2E
+/* Offsets into shared_info_t. */
+#define evtchn_upcall_pending          /* 0 */
+#define evtchn_upcall_mask             1
Erk... Can we get these into asm-offsets?

Hmm, we put the vcpu shift in, guess we missed that.  Thanks for noticing.

+#ifdef CONFIG_SMP
+/* Set %esi to point to the appropriate vcpu structure */
+#define GET_VCPU_INFO          movl TI_cpu(%ebp),%esi                  ; \
+                               shl  $SIZEOF_VCPU_INFO_SHIFT,%esi       ; \
+                               addl HYPERVISOR_shared_info,%esi
+#define GET_VCPU_INFO          movl HYPERVISOR_shared_info,%esi
+/* The following end up using/clobbering %esi, because of GET_VCPU_INFO */
+#define __DISABLE_INTERRUPTS   movb $1,evtchn_upcall_mask(%esi)
+#define DISABLE_INTERRUPTS     GET_VCPU_INFO                           ; \
+                               __DISABLE_INTERRUPTS
+#define ENABLE_INTERRUPTS      GET_VCPU_INFO                           ; \
+                               movb $0,evtchn_upcall_mask(%esi)
+#define __TEST_PENDING         testb $0xFF,evtchn_upcall_pending(%esi)
Actually, is it possible to move these to a header somewhere?  In the
paravirt_ops patches I used the names CLI and STI (copied from the VMI
patches), but didn't allow them to clobber any regs.  They're defined in

Sure, although it's only used here.  Got a preference?

It might be an idea to use something other than STI, CLI and CPUID, since the assembler is case-insensitive. We've already had one bug where CPUID didn't get replaced and the assembler quietly accepted it as-is.


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>