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From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	Avi Kivity <avi.kivity@gmail.com>, Gleb Natapov <gleb@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: [PATCH v2 06/12] KVM: MMU: introduce a static table to map guest access to spte access
Date: Wed, 23 Jan 2013 18:07:20 +0800	[thread overview]
Message-ID: <50FFB658.6040205@linux.vnet.ibm.com> (raw)
In-Reply-To: <50FFB5A1.5090708@linux.vnet.ibm.com>

It makes set_spte more clean and reduces branch prediction

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
 arch/x86/kvm/mmu.c |   37 ++++++++++++++++++++++++++-----------
 1 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 43b7e0c..a8a9c0e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -235,6 +235,29 @@ static inline u64 rsvd_bits(int s, int e)
 	return ((1ULL << (e - s + 1)) - 1) << s;
 }

+static u64 gaccess_to_spte_access[ACC_ALL + 1];
+static void build_access_table(void)
+{
+	int access;
+
+	for (access = 0; access < ACC_ALL + 1; access++) {
+		u64 spte_access = 0;
+
+		if (access & ACC_EXEC_MASK)
+			spte_access |= shadow_x_mask;
+		else
+			spte_access |= shadow_nx_mask;
+
+		if (access & ACC_USER_MASK)
+			spte_access |= shadow_user_mask;
+
+		if (access & ACC_WRITE_MASK)
+			spte_access |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
+
+		gaccess_to_spte_access[access] = spte_access;
+	}
+}
+
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 		u64 dirty_mask, u64 nx_mask, u64 x_mask)
 {
@@ -243,6 +266,7 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 	shadow_dirty_mask = dirty_mask;
 	shadow_nx_mask = nx_mask;
 	shadow_x_mask = x_mask;
+	build_access_table();
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);

@@ -2391,20 +2415,11 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 	if (!speculative)
 		spte |= shadow_accessed_mask;

-	if (pte_access & ACC_EXEC_MASK)
-		spte |= shadow_x_mask;
-	else
-		spte |= shadow_nx_mask;
-
-	if (pte_access & ACC_USER_MASK)
-		spte |= shadow_user_mask;
-
-	if (pte_access & ACC_WRITE_MASK)
-		spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
-
 	if (level > PT_PAGE_TABLE_LEVEL)
 		spte |= PT_PAGE_SIZE_MASK;

+	spte |= gaccess_to_spte_access[pte_access];
+
 	if (tdp_enabled)
 		spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
 			kvm_is_mmio_pfn(pfn));
-- 
1.7.7.6


  parent reply	other threads:[~2013-01-23 10:07 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-23 10:04 [PATCH v2 01/12] KVM: MMU: lazily drop large spte Xiao Guangrong
2013-01-23 10:04 ` [PATCH v2 02/12] KVM: MMU: cleanup mapping-level Xiao Guangrong
2013-01-23 10:05 ` [PATCH v2 03/12] KVM: MMU: simplify mmu_set_spte Xiao Guangrong
2013-01-29  0:21   ` Marcelo Tosatti
2013-01-29  2:55     ` Xiao Guangrong
2013-01-29 21:53       ` Marcelo Tosatti
2013-01-30  3:22         ` Xiao Guangrong
2013-01-23 10:06 ` [PATCH v2 04/12] KVM: MMU: simplify set_spte Xiao Guangrong
2013-01-23 10:06 ` [PATCH v2 05/12] KVM: MMU: introduce vcpu_adjust_access Xiao Guangrong
2013-01-24 10:36   ` Gleb Natapov
2013-01-24 11:33     ` Xiao Guangrong
2013-01-23 10:07 ` Xiao Guangrong [this message]
2013-01-25  0:15   ` [PATCH v2 06/12] KVM: MMU: introduce a static table to map guest access to spte access Marcelo Tosatti
2013-01-25  2:46     ` Xiao Guangrong
2013-01-29  0:07       ` Marcelo Tosatti
2013-01-29  1:07         ` Marcelo Tosatti
2013-01-29 13:16           ` Gleb Natapov
2013-01-30  3:53           ` Xiao Guangrong
2013-01-23 10:07 ` [PATCH v2 07/12] KVM: MMU: remove pt_access in mmu_set_spte Xiao Guangrong
2013-01-23 10:08 ` [PATCH v2 08/12] KVM: MMU: cleanup __direct_map Xiao Guangrong
2013-01-23 10:09 ` [PATCH v2 09/12] KVM: MMU: introduce mmu_spte_establish Xiao Guangrong
2013-01-23 10:09 ` [PATCH v2 10/12] KVM: MMU: unify the code of walking pte list Xiao Guangrong
2013-01-27 13:28   ` Gleb Natapov
2013-01-29  3:01     ` Xiao Guangrong
2013-01-23 10:10 ` [PATCH v2 11/12] KVM: MMU: fix spte assertion Xiao Guangrong
2013-01-23 10:10 ` [PATCH v2 12/12] KVM: MMU: fast drop all spte on the pte_list Xiao Guangrong
2013-01-27 12:06 ` [PATCH v2 01/12] KVM: MMU: lazily drop large spte Gleb Natapov
2013-01-29  2:57   ` Xiao Guangrong

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