[Xen-devel] [PATCH] VMX, apicv: add boot parameter to enable/disable APIC-v dynamically

[Yang Zhang <yang.z.zhang@xxxxxxxxx>]

From: Yang Zhang <yang.z.zhang@xxxxxxxxx>

Add a boot parameter to enable/disable the APIC-v dynamically. APIC-v is
enabled by default. User can use apicv=0 to disable it.

Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index de9f592..b52408d 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -46,6 +46,9 @@ boolean_param("vpid", opt_vpid_enabled);
 static bool_t __read_mostly opt_unrestricted_guest_enabled = 1;
 boolean_param("unrestricted_guest", opt_unrestricted_guest_enabled);
 
+static bool_t __read_mostly opt_apicv_enabled = 1;
+boolean_param("apicv", opt_apicv_enabled);
+
 /*
  * 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
@@ -196,12 +199,12 @@ static int vmx_init_vmcs_config(void)
          * "APIC Register Virtualization" and "Virtual Interrupt Delivery"
          * can be set only when "use TPR shadow" is set
          */
-        if ( _vmx_cpu_based_exec_control & CPU_BASED_TPR_SHADOW )
+        if ( _vmx_cpu_based_exec_control & CPU_BASED_TPR_SHADOW &&
+                opt_apicv_enabled )
             opt |= SECONDARY_EXEC_APIC_REGISTER_VIRT |
                    SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
                    SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
 
-
         _vmx_secondary_exec_control = adjust_vmx_controls(
             "Secondary Exec Control", min, opt,
             MSR_IA32_VMX_PROCBASED_CTLS2, &mismatch);
-- 
1.7.1


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