[PATCH v3 4/4] Enabling Access bit when doing memory swapping

[PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Xudong Hao]

<Re-send>

Enabling Access bit when doing memory swapping.

Changes from v2:
-Still using claer_bit() function to make sure it's atomic operation.

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/kvm/mmu.c |   14 ++++++++------
 arch/x86/kvm/vmx.c |    6 ++++--
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72102e0..c2fef8e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1242,7 +1242,8 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 	int young = 0;
 
 	/*
-	 * Emulate the accessed bit for EPT, by checking if this page has
+	 * In case of absence of EPT Access and Dirty Bits supports,
+	 * emulate the accessed bit for EPT, by checking if this page has
 	 * an EPT mapping, and clearing it if it does. On the next access,
 	 * a new EPT mapping will be established.
 	 * This has some overhead, but not as much as the cost of swapping
@@ -1253,11 +1254,12 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 
 	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
 	     sptep = rmap_get_next(&iter)) {
-		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		BUG_ON(!is_shadow_present_pte(*sptep));
 
-		if (*sptep & PT_ACCESSED_MASK) {
+		if (*sptep & shadow_accessed_mask) {
 			young = 1;
-			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
+			clear_bit((ffs(shadow_accessed_mask) - 1),
+				 (unsigned long *)sptep);
 		}
 	}
 
@@ -1281,9 +1283,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 
 	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
 	     sptep = rmap_get_next(&iter)) {
-		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		BUG_ON(!is_shadow_present_pte(*sptep));
 
-		if (*sptep & PT_ACCESSED_MASK) {
+		if (*sptep & shadow_accessed_mask) {
 			young = 1;
 			break;
 		}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 32eb588..ea6390e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7275,8 +7275,10 @@ static int __init vmx_init(void)
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
 
 	if (enable_ept) {
-		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
-				VMX_EPT_EXECUTABLE_MASK);
+		kvm_mmu_set_mask_ptes(0ull,
+			(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
+			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
+			0ull, VMX_EPT_EXECUTABLE_MASK);
 		ept_set_mmio_spte_mask();
 		kvm_enable_tdp();
 	} else
-- 
1.5.6

RE: [PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Hao, Xudong]

Hi, Avi

Will these patches be accepted if no other comments?

Thanks,
-Xudong


> -----Original Message-----
> From: Hao, Xudong
> Sent: Tuesday, May 22, 2012 11:23 AM
> To: avi@redhat.com
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; mtosatti@redhat.com;
> takuya.yoshikawa@gmail.com; Zhang, Xiantao; Hao, Xudong; Shan, Haitao
> Subject: [PATCH v3 4/4] Enabling Access bit when doing memory swapping
> 
> <Re-send>
> 
> Enabling Access bit when doing memory swapping.
> 
> Changes from v2:
> -Still using claer_bit() function to make sure it's atomic operation.
> 
> Signed-off-by: Haitao Shan <haitao.shan@intel.com>
> Signed-off-by: Xudong Hao <xudong.hao@intel.com>
> ---
>  arch/x86/kvm/mmu.c |   14 ++++++++------
>  arch/x86/kvm/vmx.c |    6 ++++--
>  2 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 72102e0..c2fef8e 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1242,7 +1242,8 @@ static int kvm_age_rmapp(struct kvm *kvm,
> unsigned long *rmapp,
>  	int young = 0;
> 
>  	/*
> -	 * Emulate the accessed bit for EPT, by checking if this page has
> +	 * In case of absence of EPT Access and Dirty Bits supports,
> +	 * emulate the accessed bit for EPT, by checking if this page has
>  	 * an EPT mapping, and clearing it if it does. On the next access,
>  	 * a new EPT mapping will be established.
>  	 * This has some overhead, but not as much as the cost of swapping
> @@ -1253,11 +1254,12 @@ static int kvm_age_rmapp(struct kvm *kvm,
> unsigned long *rmapp,
> 
>  	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
>  	     sptep = rmap_get_next(&iter)) {
> -		BUG_ON(!(*sptep & PT_PRESENT_MASK));
> +		BUG_ON(!is_shadow_present_pte(*sptep));
> 
> -		if (*sptep & PT_ACCESSED_MASK) {
> +		if (*sptep & shadow_accessed_mask) {
>  			young = 1;
> -			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
> +			clear_bit((ffs(shadow_accessed_mask) - 1),
> +				 (unsigned long *)sptep);
>  		}
>  	}
> 
> @@ -1281,9 +1283,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm,
> unsigned long *rmapp,
> 
>  	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
>  	     sptep = rmap_get_next(&iter)) {
> -		BUG_ON(!(*sptep & PT_PRESENT_MASK));
> +		BUG_ON(!is_shadow_present_pte(*sptep));
> 
> -		if (*sptep & PT_ACCESSED_MASK) {
> +		if (*sptep & shadow_accessed_mask) {
>  			young = 1;
>  			break;
>  		}
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 32eb588..ea6390e 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7275,8 +7275,10 @@ static int __init vmx_init(void)
>  	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
> 
>  	if (enable_ept) {
> -		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
> -				VMX_EPT_EXECUTABLE_MASK);
> +		kvm_mmu_set_mask_ptes(0ull,
> +			(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
> +			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
> +			0ull, VMX_EPT_EXECUTABLE_MASK);
>  		ept_set_mmio_spte_mask();
>  		kvm_enable_tdp();
>  	} else
> --
> 1.5.6

RE: [PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Hao, Xudong]

> -----Original Message-----
> From: Hao, Xudong
> Sent: Wednesday, May 23, 2012 9:31 PM
> To: avi@redhat.com
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; mtosatti@redhat.com;
> takuya.yoshikawa@gmail.com; Zhang, Xiantao; Shan, Haitao
> Subject: RE: [PATCH v3 4/4] Enabling Access bit when doing memory swapping
> 
> Hi, Avi
> 
> Will these patches be accepted if no other comments?
> 
> Thanks,
> -Xudong
> 
> 
> > -----Original Message-----
> > From: Hao, Xudong
> > Sent: Tuesday, May 22, 2012 11:23 AM
> > To: avi@redhat.com
> > Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> mtosatti@redhat.com;
> > takuya.yoshikawa@gmail.com; Zhang, Xiantao; Hao, Xudong; Shan, Haitao
> > Subject: [PATCH v3 4/4] Enabling Access bit when doing memory swapping
> >
> > <Re-send>
> >
> > Enabling Access bit when doing memory swapping.
> >
> > Changes from v2:
> > -Still using claer_bit() function to make sure it's atomic operation.
> >
> > Signed-off-by: Haitao Shan <haitao.shan@intel.com>
> > Signed-off-by: Xudong Hao <xudong.hao@intel.com>
> > ---
> >  arch/x86/kvm/mmu.c |   14 ++++++++------
> >  arch/x86/kvm/vmx.c |    6 ++++--
> >  2 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index 72102e0..c2fef8e 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -1242,7 +1242,8 @@ static int kvm_age_rmapp(struct kvm *kvm,
> > unsigned long *rmapp,
> >  	int young = 0;
> >
> >  	/*
> > -	 * Emulate the accessed bit for EPT, by checking if this page has
> > +	 * In case of absence of EPT Access and Dirty Bits supports,
> > +	 * emulate the accessed bit for EPT, by checking if this page has
> >  	 * an EPT mapping, and clearing it if it does. On the next access,
> >  	 * a new EPT mapping will be established.
> >  	 * This has some overhead, but not as much as the cost of swapping
> > @@ -1253,11 +1254,12 @@ static int kvm_age_rmapp(struct kvm *kvm,
> > unsigned long *rmapp,
> >
> >  	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
> >  	     sptep = rmap_get_next(&iter)) {
> > -		BUG_ON(!(*sptep & PT_PRESENT_MASK));
> > +		BUG_ON(!is_shadow_present_pte(*sptep));
> >
> > -		if (*sptep & PT_ACCESSED_MASK) {
> > +		if (*sptep & shadow_accessed_mask) {
> >  			young = 1;
> > -			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
> > +			clear_bit((ffs(shadow_accessed_mask) - 1),
> > +				 (unsigned long *)sptep);
> >  		}
> >  	}
> >
> > @@ -1281,9 +1283,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm,
> > unsigned long *rmapp,
> >
> >  	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
> >  	     sptep = rmap_get_next(&iter)) {
> > -		BUG_ON(!(*sptep & PT_PRESENT_MASK));
> > +		BUG_ON(!is_shadow_present_pte(*sptep));
> >
> > -		if (*sptep & PT_ACCESSED_MASK) {
> > +		if (*sptep & shadow_accessed_mask) {
> >  			young = 1;
> >  			break;
> >  		}
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index 32eb588..ea6390e 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -7275,8 +7275,10 @@ static int __init vmx_init(void)
> >  	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
> >
> >  	if (enable_ept) {
> > -		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
> > -				VMX_EPT_EXECUTABLE_MASK);
> > +		kvm_mmu_set_mask_ptes(0ull,
> > +			(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
> > +			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
> > +			0ull, VMX_EPT_EXECUTABLE_MASK);
> >  		ept_set_mmio_spte_mask();
> >  		kvm_enable_tdp();
> >  	} else
> > --
> > 1.5.6

Hi, Avi

Do you have other comments for this series of patches?

Re: [PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Avi Kivity]

On 05/23/2012 04:31 PM, Hao, Xudong wrote:
> Hi, Avi
> 
> Will these patches be accepted if no other comments?
> 

I can't see the other patches (use git send-email if possible) but this
one looks fine.


-- 
error compiling committee.c: too many arguments to function

RE: [PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Hao, Xudong]

> -----Original Message-----
> From: Avi Kivity [mailto:avi@redhat.com]
> Sent: Monday, May 28, 2012 6:37 PM
> To: Hao, Xudong
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; mtosatti@redhat.com;
> takuya.yoshikawa@gmail.com; Zhang, Xiantao; Shan, Haitao
> Subject: Re: [PATCH v3 4/4] Enabling Access bit when doing memory swapping
> 
> On 05/23/2012 04:31 PM, Hao, Xudong wrote:
> > Hi, Avi
> >
> > Will these patches be accepted if no other comments?
> >
> 
> I can't see the other patches (use git send-email if possible) but this
> one looks fine.
> 

Ok, I sent other 3 patches just now.

> 
> --
> error compiling committee.c: too many arguments to function

Re: [PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Avi Kivity]

On 05/22/2012 06:23 AM, Xudong Hao wrote:
> <Re-send>
> 
> Enabling Access bit when doing memory swapping.
> 
> Changes from v2:
> -Still using claer_bit() function to make sure it's atomic operation.
> 

Thanks, applied.


-- 
error compiling committee.c: too many arguments to function

[PATCH v3 4/4] Enabling Access bit when doing memory swapping

[Xudong Hao]

Enabling Access bit when doing memory swapping.

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/kvm/mmu.c |   14 ++++++++------
 arch/x86/kvm/vmx.c |    6 ++++--
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72102e0..c2fef8e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1242,7 +1242,8 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
        int young = 0;

        /*
-        * Emulate the accessed bit for EPT, by checking if this page has
+        * In case of absence of EPT Access and Dirty Bits supports,
+        * emulate the accessed bit for EPT, by checking if this page has
         * an EPT mapping, and clearing it if it does. On the next access,
         * a new EPT mapping will be established.
         * This has some overhead, but not as much as the cost of swapping
@@ -1253,11 +1254,12 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,

        for (sptep = rmap_get_first(*rmapp, &iter); sptep;
             sptep = rmap_get_next(&iter)) {
-               BUG_ON(!(*sptep & PT_PRESENT_MASK));
+               BUG_ON(!is_shadow_present_pte(*sptep));

-               if (*sptep & PT_ACCESSED_MASK) {
+               if (*sptep & shadow_accessed_mask) {
                        young = 1;
-                       clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
+                       clear_bit((ffs(shadow_accessed_mask) - 1),
+                                (unsigned long *)sptep);
                }
        }

@@ -1281,9 +1283,9 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,

        for (sptep = rmap_get_first(*rmapp, &iter); sptep;
             sptep = rmap_get_next(&iter)) {
-               BUG_ON(!(*sptep & PT_PRESENT_MASK));
+               BUG_ON(!is_shadow_present_pte(*sptep));

-               if (*sptep & PT_ACCESSED_MASK) {
+               if (*sptep & shadow_accessed_mask) {
                        young = 1;
                        break;
                }
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 32eb588..ea6390e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7275,8 +7275,10 @@ static int __init vmx_init(void)
        vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);

        if (enable_ept) {
-               kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
-                               VMX_EPT_EXECUTABLE_MASK);
+               kvm_mmu_set_mask_ptes(0ull,
+                       (enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
+                       (enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
+                       0ull, VMX_EPT_EXECUTABLE_MASK);
                ept_set_mmio_spte_mask();
                kvm_enable_tdp();
        } else