hv: config: add an option to disable mce on psc workaround

Add a option MCE_ON_PSC_WORKAROUND_DISABLED to disable the software
workaround for the issue Machine Check Error on Page Size Change.

Tracked-On: #4121
Signed-off-by: Binbin Wu <binbin.wu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/Kconfig

@@ -21,10 +21,10 @@ config LOGICAL_PARTITION
 	help
 	  This scenario will run two pre-launched VMs.
 
-config INDUSTRY 
+config INDUSTRY
 	bool "Industry VMs"
 	help
-	  This scenario is a typical scenario for industry usage with 4 VMs: 
+	  This scenario is a typical scenario for industry usage with 4 VMs:
 	  one pre-launched SOS VM, one post-launched Standard VM for HMI, one or two
 	  post-launched  RT VM for real-time control.
 
@@ -303,3 +303,12 @@ config MAX_KATA_VM_NUM
 	int "Maximum number of Kata Containers in SOS"
 	range 0 1
 	default 0
+
+config MCE_ON_PSC_WORKAROUND_DISABLED
+	bool "Force to disable software workaround for Machine Check Error on Page Size Change"
+	default n
+	help
+	  By default, software workaround for Machine Check Error on Page Size Change is
+	  conditionally applied to the models that may be affected by the issue. However,
+	  the software workaround has negative impact on performance. If all the guest VMs
+	  are trusted, for performance, this option can be set.

hypervisor/arch/x86/security.c

@@ -185,6 +185,12 @@ void set_fs_base(void)
 }
 #endif
 
+#ifdef CONFIG_MCE_ON_PSC_WORKAROUND_DISABLED
+bool is_ept_force_4k_ipage(void)
+{
+	return false;
+}
+#else
 bool is_ept_force_4k_ipage(void)
 {
 	bool force_4k_ipage = true;
@@ -229,3 +235,4 @@ bool is_ept_force_4k_ipage(void)
 
 	return force_4k_ipage;
 }
+#endif