From 8672b7217a234c41d425a63b171af809e1169842 Mon Sep 17 00:00:00 2001
From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Date: Mon, 2 Aug 2010 16:14:04 +0800
Subject: [PATCH] KVM: MMU: move bits lost judgement into a separate function
Introduce spte_has_volatile_bits() function to judge whether spte
bits will miss, it's more readable and can help us to cleanup code
later
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/mmu.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e430a383ad151..c07b9a200bc83 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -299,6 +299,20 @@ static u64 __xchg_spte(u64 *sptep, u64 new_spte)
#endif
}
+static bool spte_has_volatile_bits(u64 spte)
+{
+ if (!shadow_accessed_mask)
+ return false;
+
+ if (!is_shadow_present_pte(spte))
+ return false;
+
+ if (spte & shadow_accessed_mask)
+ return false;
+
+ return true;
+}
+
static void update_spte(u64 *sptep, u64 new_spte)
{
u64 old_spte;
@@ -679,14 +693,14 @@ static void set_spte_track_bits(u64 *sptep, u64 new_spte)
pfn_t pfn;
u64 old_spte = *sptep;
- if (!shadow_accessed_mask || !is_shadow_present_pte(old_spte) ||
- old_spte & shadow_accessed_mask) {
+ if (!spte_has_volatile_bits(old_spte))
__set_spte(sptep, new_spte);
- } else
+ else
old_spte = __xchg_spte(sptep, new_spte);
if (!is_rmap_spte(old_spte))
return;
+
pfn = spte_to_pfn(old_spte);
if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
--
2.30.2