[Xen-devel] [PATCH 01/10] VMX: Enable EPT A/D bit support

[Kai Huang <kai.huang@xxxxxxxxxxxxxxx>]

PML requires A/D bit support so enable it for further use.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c        | 1 +
 xen/arch/x86/mm/p2m-ept.c          | 8 +++++++-
 xen/include/asm-x86/hvm/vmx/vmcs.h | 4 +++-
 xen/include/asm-x86/hvm/vmx/vmx.h  | 5 ++++-
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index d614638..2f645fe 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -103,6 +103,7 @@ static void __init vmx_display_features(void)
     P(cpu_has_vmx_tpr_shadow, "APIC TPR shadow");
     P(cpu_has_vmx_ept, "Extended Page Tables (EPT)");
     P(cpu_has_vmx_vpid, "Virtual-Processor Identifiers (VPID)");
+    P(cpu_has_vmx_ept_ad_bit, "EPT A/D bit");
     P(cpu_has_vmx_vnmi, "Virtual NMI");
     P(cpu_has_vmx_msr_bitmap, "MSR direct-access bitmap");
     P(cpu_has_vmx_unrestricted_guest, "Unrestricted Guest");
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index c2d7720..8650092 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -233,6 +233,9 @@ static int ept_split_super_page(struct p2m_domain *p2m, 
ept_entry_t *ept_entry,
     if ( !ept_set_middle_entry(p2m, &new_ept) )
         return 0;
 
+    /* It's better to copy A bit of Middle entry from original entry */
+    new_ept.a = ept_entry->a;
+
     table = map_domain_page(new_ept.mfn);
     trunk = 1UL << ((level - 1) * EPT_TABLE_ORDER);
 
@@ -244,7 +247,7 @@ static int ept_split_super_page(struct p2m_domain *p2m, 
ept_entry_t *ept_entry,
         epte->sp = (level > 1);
         epte->mfn += i * trunk;
         epte->snp = (iommu_enabled && iommu_snoop);
-        ASSERT(!epte->rsvd1);
+        /* A/D bits are inherited from superpage */
         ASSERT(!epte->avail3);
 
         ept_p2m_type_to_flags(epte, epte->sa_p2mt, epte->access);
@@ -1071,6 +1074,9 @@ int ept_p2m_init(struct p2m_domain *p2m)
     /* set EPT page-walk length, now it's actual walk length - 1, i.e. 3 */
     ept->ept_wl = 3;
 
+    /* Enable EPT A/D bit if it's supported by hardware */
+    ept->ept_ad = cpu_has_vmx_ept_ad_bit ? 1 : 0;
+
     if ( !zalloc_cpumask_var(&ept->synced_mask) )
         return -ENOMEM;
 
diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h 
b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 6fce6aa..4528346 100644
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -62,7 +62,8 @@ struct ept_data {
     struct {
             u64 ept_mt :3,
                 ept_wl :3,
-                rsvd   :6,
+                ept_ad :1,
+                rsvd   :5,
                 asr    :52;
         };
         u64 eptp;
@@ -226,6 +227,7 @@ extern u32 vmx_secondary_exec_control;
 #define VMX_EPT_INVEPT_INSTRUCTION              0x00100000
 #define VMX_EPT_INVEPT_SINGLE_CONTEXT           0x02000000
 #define VMX_EPT_INVEPT_ALL_CONTEXT              0x04000000
+#define VMX_EPT_AD_BIT_SUPPORT                  0x00200000
 
 #define VMX_MISC_VMWRITE_ALL                    0x20000000
 
diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h 
b/xen/include/asm-x86/hvm/vmx/vmx.h
index 91c5e18..9afd351 100644
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -37,7 +37,8 @@ typedef union {
         emt         :   3,  /* bits 5:3 - EPT Memory type */
         ipat        :   1,  /* bit 6 - Ignore PAT memory type */
         sp          :   1,  /* bit 7 - Is this a superpage? */
-        rsvd1       :   2,  /* bits 9:8 - Reserved for future use */
+        a           :   1,  /* bit 8 - Access bit */
+        d           :   1,  /* bit 9 - Dirty bit */
         recalc      :   1,  /* bit 10 - Software available 1 */
         snp         :   1,  /* bit 11 - VT-d snoop control in shared
                                EPT/VT-d usage */
@@ -261,6 +262,8 @@ extern uint8_t posted_intr_vector;
     (vmx_ept_vpid_cap & VMX_EPT_SUPERPAGE_2MB)
 #define cpu_has_vmx_ept_invept_single_context   \
     (vmx_ept_vpid_cap & VMX_EPT_INVEPT_SINGLE_CONTEXT)
+#define cpu_has_vmx_ept_ad_bit                  \
+    (vmx_ept_vpid_cap & VMX_EPT_AD_BIT_SUPPORT)
 
 #define EPT_2MB_SHIFT     16
 #define EPT_1GB_SHIFT     17
-- 
2.1.0


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