3 files changed, 32 insertions, 5 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b6d61c353fe5..a4d7b647867f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1414,7 +1414,7 @@ static void __init xen_boot_params_init_edd(void)
  * is PVH which is not going to use xen_load_gdt_boot or other
  * __init functions.
  */
-void __ref xen_setup_gdt(int cpu)
+static void __ref xen_setup_gdt(int cpu)
 {
         if (xen_feature(XENFEAT_auto_translated_physmap)) {
 #ifdef CONFIG_X86_64
@@ -1462,13 +1462,40 @@ void __ref xen_setup_gdt(int cpu)
         pv_cpu_ops.load_gdt = xen_load_gdt;
 }
 
+/*
+ * A PV guest starts with default flags that are not set for PVH, set them
+ * here asap.
+ */
+static void xen_pvh_set_cr_flags(int cpu)
+{
+
+        /* Some of these are setup in 'secondary_startup_64'. The others:
+         * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests
+         * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */
+        write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM);
+}
+
+/*
+ * Note, that it is ref - because the only caller of this after init
+ * is PVH which is not going to use xen_load_gdt_boot or other
+ * __init functions.
+ */
+void __ref xen_pvh_secondary_vcpu_init(int cpu)
+{
+        xen_setup_gdt(cpu);
+        xen_pvh_set_cr_flags(cpu);
+}
+
 static void __init xen_pvh_early_guest_init(void)
 {
         if (!xen_feature(XENFEAT_auto_translated_physmap))
                 return;
 
-        if (xen_feature(XENFEAT_hvm_callback_vector))
-                xen_have_vector_callback = 1;
+        if (!xen_feature(XENFEAT_hvm_callback_vector))
+                return;
+
+        xen_have_vector_callback = 1;
+        xen_pvh_set_cr_flags(0);
 
 #ifdef CONFIG_X86_32
         BUG(); /* PVH: Implement proper support. */
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 5e46190133b2..a18eadd8bb40 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -105,7 +105,7 @@ static void cpu_bringup_and_idle(int cpu)
 #ifdef CONFIG_X86_64
         if (xen_feature(XENFEAT_auto_translated_physmap) &&
             xen_feature(XENFEAT_supervisor_mode_kernel))
-                xen_setup_gdt(cpu);
+                xen_pvh_secondary_vcpu_init(cpu);
 #endif
         cpu_bringup();
         cpu_startup_entry(CPUHP_ONLINE);
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 9059c24ed564..1cb6f4c37300 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -123,5 +123,5 @@ __visible void xen_adjust_exception_frame(void);
 
 extern int xen_panic_handler_init(void);
 
-void xen_setup_gdt(int cpu);
+void xen_pvh_secondary_vcpu_init(int cpu);
 #endif /* XEN_OPS_H */