[Xen-devel] [PATCH 07/10] VMX: handle PML enabling in vmx_vcpu_initialise

[Kai Huang <kai.huang@xxxxxxxxxxxxxxx>]

It's possible domain has already been in log-dirty mode when creating vcpu, in
which case we should enable PML for this vcpu if PML has been enabled for the
domain.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 453bcc5..fce3aa2 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -116,6 +116,30 @@ static int vmx_vcpu_initialise(struct vcpu *v)
         return rc;
     }
 
+    /*
+     * It's rare but still possible that domain has already been in log-dirty
+     * mode when vcpu is being created (commented by Tim), in which case we
+     * should enable PML for this vcpu if PML has been enabled for the domain,
+     * and failure to enable results in failure of creating this vcpu.
+     *
+     * Note even there's no vcpu created for the domain, vmx_domain_enable_pml
+     * will return successful in which case vmx_domain_pml_enabled will also
+     * return true. And even this is the first vcpu to be created with
+     * vmx_domain_pml_enabled being true, failure of enabling PML still results
+     * in failure of creating vcpu, to avoid complicated logic to revert PML
+     * style EPT table to non-PML style EPT table.
+     */
+    if ( vmx_domain_pml_enabled(v->domain) )
+    {
+        if ( (rc = vmx_vcpu_enable_pml(v)) != 0 )
+        {
+            dprintk(XENLOG_ERR, "Failed to enable PML for vcpu %d\n",
+                    v->vcpu_id);
+            vmx_destroy_vmcs(v);
+            return rc;
+        }
+    }
+
     vpmu_initialise(v);
 
     vmx_install_vlapic_mapping(v);
-- 
2.1.0


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