[Xen-devel] [PATCH 02/10] VMX: New parameter to control PML enabling

[Kai Huang <kai.huang@xxxxxxxxxxxxxxx>]

A top level EPT parameter "ept=<options>" and a sub boolean "pml_enable" are
added to control PML. Other booleans can be further added for any other EPT
related features.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 2f645fe..9b20a4b 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -50,6 +50,16 @@ boolean_param("unrestricted_guest", 
opt_unrestricted_guest_enabled);
 static bool_t __read_mostly opt_apicv_enabled = 1;
 boolean_param("apicv", opt_apicv_enabled);
 
+static void parse_ept_param(char *s);
+/*
+ * The 'ept' parameter controls functionalities that depend on, or impact the
+ * EPT mechanism. Optional comma separated value may contain:
+ *
+ *  pml                 Enable PML
+ */
+custom_param("ept", parse_ept_param);
+static bool_t __read_mostly pml_enable = 0;
+
 /*
  * These two parameters are used to config the controls for Pause-Loop Exiting:
  * ple_gap:    upper bound on the amount of time between two successive
@@ -92,6 +102,28 @@ DEFINE_PER_CPU(bool_t, vmxon);
 static u32 vmcs_revision_id __read_mostly;
 u64 __read_mostly vmx_basic_msr;
 
+/* Copied from parse_iommu_param */
+static void parse_ept_param(char *s)
+{
+    char *ss;
+    int val;
+
+    do {
+        val = !!strncmp(s, "no-", 3);
+        if ( !val )
+            s += 3;
+
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        if ( !strcmp(s, "pml") )
+            pml_enable = val;
+
+        s = ss + 1;
+    } while ( ss );
+}
+
 static void __init vmx_display_features(void)
 {
     int printed = 0;
-- 
2.1.0


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