Re: [PATCH][REPOST] KVM: VMX: Always return 0 for clear_flush_young() when using EPT

["Yang, Sheng" <sheng.yang@intel.com>]

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On Sunday 07 September 2008 21:31:54 Avi Kivity wrote:
> Why not to a
>
>   if (!shadow_access_mask)
>        return 0;
>
> in the beginning?

Oops...
>
> I guess returning 'old' is safer than returning 'young'.

Yeah, me too, though possibly cause thrashing.

How about this one?

--
From: Sheng Yang <sheng.yang@intel.com>
Date: Mon, 8 Sep 2008 15:12:30 +0800
Subject: [PATCH] KVM: VMX: Always return old for clear_flush_young() when 
using EPT

As well as discard fake accessed bit and dirty bit of EPT.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
---
 arch/x86/kvm/mmu.c |    4 ++++
 arch/x86/kvm/vmx.c |    3 +--
 arch/x86/kvm/vmx.h |    2 --
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a87a11e..bce3e25 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -711,6 +711,10 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long 
*rmapp)
 	u64 *spte;
 	int young = 0;

+	/* always return old for EPT */
+	if (!shadow_accessed_mask)
+		return 0;
+
 	spte = rmap_next(kvm, rmapp, NULL);
 	while (spte) {
 		int _young;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 14671f4..2d6c770 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3558,8 +3558,7 @@ static int __init vmx_init(void)
 		kvm_mmu_set_base_ptes(VMX_EPT_READABLE_MASK |
 			VMX_EPT_WRITABLE_MASK |
 			VMX_EPT_DEFAULT_MT << VMX_EPT_MT_EPTE_SHIFT);
-		kvm_mmu_set_mask_ptes(0ull, VMX_EPT_FAKE_ACCESSED_MASK,
-				VMX_EPT_FAKE_DIRTY_MASK, 0ull,
+		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
 				VMX_EPT_EXECUTABLE_MASK);
 		kvm_enable_tdp();
 	} else
diff --git a/arch/x86/kvm/vmx.h b/arch/x86/kvm/vmx.h
index 0c22e5f..41e8c10 100644
--- a/arch/x86/kvm/vmx.h
+++ b/arch/x86/kvm/vmx.h
@@ -370,8 +370,6 @@ enum vmcs_field {
 #define VMX_EPT_READABLE_MASK			0x1ull
 #define VMX_EPT_WRITABLE_MASK			0x2ull
 #define VMX_EPT_EXECUTABLE_MASK			0x4ull
-#define VMX_EPT_FAKE_ACCESSED_MASK		(1ull << 62)
-#define VMX_EPT_FAKE_DIRTY_MASK			(1ull << 63)

 #define VMX_EPT_IDENTITY_PAGETABLE_ADDR		0xfffbc000ul

--
1.5.6.5


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From 250f978cf178fce89b9e5c68007307ccddbb2868 Mon Sep 17 00:00:00 2001
From: Sheng Yang <sheng.yang@intel.com>
Date: Mon, 8 Sep 2008 15:12:30 +0800
Subject: [PATCH] KVM: VMX: Always return old for clear_flush_young() when using EPT

As well as discard fake accessed bit and dirty bit of EPT.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
---
 arch/x86/kvm/mmu.c |    4 ++++
 arch/x86/kvm/vmx.c |    3 +--
 arch/x86/kvm/vmx.h |    2 --
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a87a11e..bce3e25 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -711,6 +711,10 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
 	u64 *spte;
 	int young = 0;
 
+	/* always return old for EPT */
+	if (!shadow_accessed_mask)
+		return 0;
+
 	spte = rmap_next(kvm, rmapp, NULL);
 	while (spte) {
 		int _young;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 14671f4..2d6c770 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3558,8 +3558,7 @@ static int __init vmx_init(void)
 		kvm_mmu_set_base_ptes(VMX_EPT_READABLE_MASK |
 			VMX_EPT_WRITABLE_MASK |
 			VMX_EPT_DEFAULT_MT << VMX_EPT_MT_EPTE_SHIFT);
-		kvm_mmu_set_mask_ptes(0ull, VMX_EPT_FAKE_ACCESSED_MASK,
-				VMX_EPT_FAKE_DIRTY_MASK, 0ull,
+		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
 				VMX_EPT_EXECUTABLE_MASK);
 		kvm_enable_tdp();
 	} else
diff --git a/arch/x86/kvm/vmx.h b/arch/x86/kvm/vmx.h
index 0c22e5f..41e8c10 100644
--- a/arch/x86/kvm/vmx.h
+++ b/arch/x86/kvm/vmx.h
@@ -370,8 +370,6 @@ enum vmcs_field {
 #define VMX_EPT_READABLE_MASK			0x1ull
 #define VMX_EPT_WRITABLE_MASK			0x2ull
 #define VMX_EPT_EXECUTABLE_MASK			0x4ull
-#define VMX_EPT_FAKE_ACCESSED_MASK		(1ull << 62)
-#define VMX_EPT_FAKE_DIRTY_MASK			(1ull << 63)
 
 #define VMX_EPT_IDENTITY_PAGETABLE_ADDR		0xfffbc000ul
 
-- 
1.5.6.5