[PATCH v2 1/4] Add EPT A/D bits definitions

[PATCH v2 1/4] Add EPT A/D bits definitions

[Xudong Hao]

Add EPT A/D bits definitions.

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/include/asm/vmx.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 31f180c..de007c2 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -404,6 +404,7 @@ enum vmcs_field {
 #define VMX_EPTP_WB_BIT				(1ull << 14)
 #define VMX_EPT_2MB_PAGE_BIT			(1ull << 16)
 #define VMX_EPT_1GB_PAGE_BIT			(1ull << 17)
+#define VMX_EPT_AD_BIT					(1ull << 21)
 #define VMX_EPT_EXTENT_INDIVIDUAL_BIT		(1ull << 24)
 #define VMX_EPT_EXTENT_CONTEXT_BIT		(1ull << 25)
 #define VMX_EPT_EXTENT_GLOBAL_BIT		(1ull << 26)
@@ -415,11 +416,14 @@ enum vmcs_field {
 #define VMX_EPT_MAX_GAW				0x4
 #define VMX_EPT_MT_EPTE_SHIFT			3
 #define VMX_EPT_GAW_EPTP_SHIFT			3
+#define VMX_EPT_AD_ENABLE_BIT			(1ull << 6)
 #define VMX_EPT_DEFAULT_MT			0x6ull
 #define VMX_EPT_READABLE_MASK			0x1ull
 #define VMX_EPT_WRITABLE_MASK			0x2ull
 #define VMX_EPT_EXECUTABLE_MASK			0x4ull
 #define VMX_EPT_IPAT_BIT    			(1ull << 6)
+#define VMX_EPT_ACCESS_BIT				(1ull << 8)
+#define VMX_EPT_DIRTY_BIT				(1ull << 9)
 
 #define VMX_EPT_IDENTITY_PAGETABLE_ADDR		0xfffbc000ul
 
-- 
1.5.6

[PATCH v2 2/4] Add parameter to control A/D bits support

[Xudong Hao]

Add kernel parameter to control A/D bits support, it's on by default.

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/kvm/vmx.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3062ea9..f3858bf 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -71,6 +71,9 @@ static bool __read_mostly enable_unrestricted_guest = 1;
 module_param_named(unrestricted_guest,
 			enable_unrestricted_guest, bool, S_IRUGO);
 
+static bool __read_mostly enable_ept_ad_bits = 1;
+module_param_named(eptad, enable_ept_ad_bits, bool, S_IRUGO);
+
 static bool __read_mostly emulate_invalid_guest_state = 0;
 module_param(emulate_invalid_guest_state, bool, S_IRUGO);
 
@@ -786,6 +789,11 @@ static inline bool cpu_has_vmx_ept_4levels(void)
 	return vmx_capability.ept & VMX_EPT_PAGE_WALK_4_BIT;
 }
 
+static inline bool cpu_has_vmx_ept_ad_bits(void)
+{
+	return vmx_capability.ept & VMX_EPT_AD_BIT;
+}
+
 static inline bool cpu_has_vmx_invept_individual_addr(void)
 {
 	return vmx_capability.ept & VMX_EPT_EXTENT_INDIVIDUAL_BIT;
@@ -2624,8 +2632,12 @@ static __init int hardware_setup(void)
 	    !cpu_has_vmx_ept_4levels()) {
 		enable_ept = 0;
 		enable_unrestricted_guest = 0;
+		enable_ept_ad_bits = 0;
 	}
 
+	if (!cpu_has_vmx_ept_ad_bits())
+		enable_ept_ad_bits = 0;
+
 	if (!cpu_has_vmx_unrestricted_guest())
 		enable_unrestricted_guest = 0;
 
-- 
1.5.6

[PATCH v2 3/4] Enable EPT A/D bits if supported by turning on relevant bit in EPTP

[Xudong Hao]

In EPT page structure entry, Enable EPT A/D bits if processor supported.

Signed-off-by: Haitao Shan <haitao.shan@intel.com>
Signed-off-by: Xudong Hao <xudong.hao@intel.com>
---
 arch/x86/kvm/vmx.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f3858bf..e8003b6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3018,6 +3018,8 @@ static u64 construct_eptp(unsigned long root_hpa)
 	/* TODO write the value reading from MSR */
 	eptp = VMX_EPT_DEFAULT_MT |
 		VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
+	if (enable_ept_ad_bits)
+		eptp |= VMX_EPT_AD_ENABLE_BIT;
 	eptp |= (root_hpa & PAGE_MASK);
 
 	return eptp;
-- 
1.5.6

[PATCH v2 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 |   13 +++++++------
 arch/x86/kvm/vmx.c |    6 ++++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 07424cf..392bdf3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1232,7 +1232,8 @@ 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
@@ -1243,11 +1244,11 @@ 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);
+			*sptep &= ~shadow_accessed_mask;
 		}
 	}
 
@@ -1271,9 +1272,9 @@ 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 e8003b6..342ea2e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7259,8 +7259,10 @@ 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 v2 4/4] Enabling Access bit when doing memory swapping

[Avi Kivity]

On 05/21/2012 06:54 AM, Xudong Hao wrote:
> Enabling Access bit when doing memory swapping.
>
> @@ -1243,11 +1244,11 @@ 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);
> +			*sptep &= ~shadow_accessed_mask;
>  		}
>  	}

As Marcelo already noted, this converts an atomic operation into a
non-atomic one.


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