x86/ept: defer enabling of EPT A/D bit until PML get enabled

Existing PML implementation turns on EPT A/D bit unconditionally if PML is
supported by hardware. This works but enabling of EPT A/D bit can be deferred
until PML get enabled. There's no point in enabling the extra feature for every
domain when we're not meaning to use it (yet).

Also added ASSERT of domain having been paused to ept_flush_pml_buffers to make
it consistent with ept_enable{disable}_pml.

Sanity live migration and GUI display were tested on Broadwell Machine.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Kai Huang <kai.huang@linux.intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 3592a88847fb22d4e6d65dd68f576f5679512b1d..c11f3ecb7fefa5a93a7a7494c1820f199ea9dad2 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1553,6 +1553,30 @@ void vmx_domain_flush_pml_buffers(struct domain *d)
         vmx_vcpu_flush_pml_buffer(v);
 }
 
+static void vmx_vcpu_update_eptp(struct vcpu *v, u64 eptp)
+{
+    vmx_vmcs_enter(v);
+    __vmwrite(EPT_POINTER, eptp);
+    vmx_vmcs_exit(v);
+}
+
+/*
+ * Update EPTP data to VMCS of all vcpus of the domain. Must be called when
+ * domain is paused.
+ */
+void vmx_domain_update_eptp(struct domain *d)
+{
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+    struct vcpu *v;
+
+    ASSERT(atomic_read(&d->pause_count));
+
+    for_each_vcpu ( d, v )
+        vmx_vcpu_update_eptp(v, ept_get_eptp(&p2m->ept));
+
+    ept_sync_domain(p2m);
+}
+
 int vmx_create_vmcs(struct vcpu *v)
 {
     struct arch_vmx_struct *arch_vmx = &v->arch.hvm_vmx;

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 74ce9e0262d8ebefb0ac0c3ed112caa41d5b8202..86440fc1e05a147752ec78875c51cda8d2373ced 100644 (file)
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -1129,21 +1129,39 @@ void ept_sync_domain(struct p2m_domain *p2m)
 
 static void ept_enable_pml(struct p2m_domain *p2m)
 {
+    /* Domain must have been paused */
+    ASSERT(atomic_read(&p2m->domain->pause_count));
+
     /*
-     * No need to check if vmx_domain_enable_pml has succeeded or not, as
+     * No need to return whether vmx_domain_enable_pml has succeeded, as
      * ept_p2m_type_to_flags will do the check, and write protection will be
      * used if PML is not enabled.
      */
-    vmx_domain_enable_pml(p2m->domain);
+    if ( vmx_domain_enable_pml(p2m->domain) )
+        return;
+
+    /* Enable EPT A/D bit for PML */
+    p2m->ept.ept_ad = 1;
+    vmx_domain_update_eptp(p2m->domain);
 }
 
 static void ept_disable_pml(struct p2m_domain *p2m)
 {
+    /* Domain must have been paused */
+    ASSERT(atomic_read(&p2m->domain->pause_count));
+
     vmx_domain_disable_pml(p2m->domain);
+
+    /* Disable EPT A/D bit */
+    p2m->ept.ept_ad = 0;
+    vmx_domain_update_eptp(p2m->domain);
 }
 
 static void ept_flush_pml_buffers(struct p2m_domain *p2m)
 {
+    /* Domain must have been paused */
+    ASSERT(atomic_read(&p2m->domain->pause_count));
+
     vmx_domain_flush_pml_buffers(p2m->domain);
 }
 
@@ -1166,8 +1184,6 @@ int ept_p2m_init(struct p2m_domain *p2m)
 
     if ( cpu_has_vmx_pml )
     {
-        /* Enable EPT A/D bits if we are going to use PML. */
-        ept->ept_ad = cpu_has_vmx_pml ? 1 : 0;
         p2m->enable_hardware_log_dirty = ept_enable_pml;
         p2m->disable_hardware_log_dirty = ept_disable_pml;
         p2m->flush_hardware_cached_dirty = ept_flush_pml_buffers;

diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 1a71de65acd0db597e1fc07349731ea972ece978..865d9fc51e5b8c27d647918321b62195c69366a6 100644 (file)
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -517,6 +517,8 @@ int vmx_domain_enable_pml(struct domain *d);
 void vmx_domain_disable_pml(struct domain *d);
 void vmx_domain_flush_pml_buffers(struct domain *d);
 
+void vmx_domain_update_eptp(struct domain *d);
+
 #endif /* ASM_X86_HVM_VMX_VMCS_H__ */
 
 /*