[Xen-changelog] [linux-2.6.18-xen] x86: Check for XENFEAT_mmu_pt_update_preserve_ad before attempting to

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1200490042 0
# Node ID 414030b3a3fd1ab240f52d03fcfa296bc55a40a0
# Parent  854690f06ed9a154b7f3bea75ba7b2b53afc3e29
x86: Check for XENFEAT_mmu_pt_update_preserve_ad before attempting to
use new mmu_update() hypercall. Older Xen versions are noisy if the
unsupported hypercall is attempted.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 arch/i386/mm/hypervisor.c              |    3 +
 include/xen/interface/arch-x86/cpuid.h |   68 +++++++++++++++++++++++++++++++++
 include/xen/interface/features.h       |    3 +
 3 files changed, 74 insertions(+)

diff -r 854690f06ed9 -r 414030b3a3fd arch/i386/mm/hypervisor.c
--- a/arch/i386/mm/hypervisor.c Tue Jan 15 15:59:31 2008 +0000
+++ b/arch/i386/mm/hypervisor.c Wed Jan 16 13:27:22 2008 +0000
@@ -559,6 +559,9 @@ int xen_change_pte_range(struct mm_struc
        pte_t *pte;
        spinlock_t *ptl;
 
+       if (!xen_feature(XENFEAT_mmu_pt_update_preserve_ad))
+               return 0;
+
        pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
        do {
                if (pte_present(*pte)) {
diff -r 854690f06ed9 -r 414030b3a3fd include/xen/interface/arch-x86/cpuid.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/xen/interface/arch-x86/cpuid.h    Wed Jan 16 13:27:22 2008 +0000
@@ -0,0 +1,68 @@
+/******************************************************************************
+ * arch-x86/cpuid.h
+ * 
+ * CPUID interface to Xen.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * 
+ * Copyright (c) 2007 Citrix Systems, Inc.
+ * 
+ * Authors:
+ *    Keir Fraser <keir.fraser@xxxxxxxxxx>
+ */
+
+#ifndef __XEN_PUBLIC_ARCH_X86_CPUID_H__
+#define __XEN_PUBLIC_ARCH_X86_CPUID_H__
+
+/* Xen identification leaves start at 0x40000000. */
+#define XEN_CPUID_FIRST_LEAF 0x40000000
+#define XEN_CPUID_LEAF(i)    (XEN_CPUID_FIRST_LEAF + (i))
+
+/*
+ * Leaf 1 (0x40000000)
+ * EAX: Largest Xen-information leaf. All leaves up to an including @EAX
+ *      are supported by the Xen host.
+ * EBX-EDX: "XenVMMXenVMM" signature, allowing positive identification
+ *      of a Xen host.
+ */
+#define XEN_CPUID_SIGNATURE_EBX 0x566e6558 /* "XenV" */
+#define XEN_CPUID_SIGNATURE_ECX 0x65584d4d /* "MMXe" */
+#define XEN_CPUID_SIGNATURE_EDX 0x4d4d566e /* "nVMM" */
+
+/*
+ * Leaf 2 (0x40000001)
+ * EAX[31:16]: Xen major version.
+ * EAX[15: 0]: Xen minor version.
+ * EBX-EDX: Reserved (currently all zeroes).
+ */
+
+/*
+ * Leaf 3 (0x40000002)
+ * EAX: Number of hypercall transfer pages. This register is always guaranteed
+ *      to specify one hypercall page.
+ * EBX: Base address of Xen-specific MSRs.
+ * ECX: Features 1. Unused bits are set to zero.
+ * EDX: Features 2. Unused bits are set to zero.
+ */
+
+/* Does the host support MMU_PT_UPDATE_PRESERVE_AD for this guest? */
+#define _XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD 0
+#define XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD  (1u<<0)
+
+#endif /* __XEN_PUBLIC_ARCH_X86_CPUID_H__ */
diff -r 854690f06ed9 -r 414030b3a3fd include/xen/interface/features.h
--- a/include/xen/interface/features.h  Tue Jan 15 15:59:31 2008 +0000
+++ b/include/xen/interface/features.h  Wed Jan 16 13:27:22 2008 +0000
@@ -56,6 +56,9 @@
  */
 #define XENFEAT_pae_pgdir_above_4gb        4
 
+/* x86: Does this Xen host support the MMU_PT_UPDATE_PRESERVE_AD hypercall? */
+#define XENFEAT_mmu_pt_update_preserve_ad  5
+
 #define XENFEAT_NR_SUBMAPS 1
 
 #endif /* __XEN_PUBLIC_FEATURES_H__ */

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