Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932226Ab2JQODs (ORCPT ); Wed, 17 Oct 2012 10:03:48 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:44568 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757104Ab2JQODp (ORCPT ); Wed, 17 Oct 2012 10:03:45 -0400 From: Konrad Rzeszutek Wilk To: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, lenb@kernel.org, linux-acpi@vger.kernel.org, hpa@zytor.com, x86@kernel.org Cc: Konrad Rzeszutek Wilk Subject: [PATCH 2/4] xen/lowlevel: Implement pvop call for load_idt (sidt). Date: Wed, 17 Oct 2012 09:49:44 -0400 Message-Id: <1350481786-4969-3-git-send-email-konrad.wilk@oracle.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1350481786-4969-1-git-send-email-konrad.wilk@oracle.com> References: <1350481786-4969-1-git-send-email-konrad.wilk@oracle.com> X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1852 Lines: 55 In the past it used to point to 'sidt' (native_store_idt) operation which is a non-privileged operation. This resulted in the 'struct desc_ptr' value containing the address of Xen's IDT table, instead of the IDT table that Linux thinks its using. The end result is that doing: store_idt(&desc); load_idt(&desc); would blow up b/c xen_load_idt would try to parse the IDT contents (desc) and de-reference a virtual address that is outside Linux's __va (it is in Xen's virtual address). With this patch we are providing the last written IDT address. Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/enlighten.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index e3497f2..f29d6d6 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -777,7 +777,13 @@ static void xen_load_idt(const struct desc_ptr *desc) spin_unlock(&lock); } +static void xen_store_idt(struct desc_ptr *dtr) +{ + const struct desc_ptr *desc = &__get_cpu_var(idt_desc); + dtr->address = desc->address; + dtr->size = desc->size; +} /* Write a GDT descriptor entry. Ignore LDT descriptors, since they're handled differently. */ static void xen_write_gdt_entry(struct desc_struct *dt, int entry, @@ -1200,7 +1206,7 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { .free_ldt = xen_free_ldt, .store_gdt = native_store_gdt, - .store_idt = native_store_idt, + .store_idt = xen_store_idt, .store_tr = xen_store_tr, .write_ldt_entry = xen_write_ldt_entry, -- 1.7.7.6 -- 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/