diff --git a/xen/arch/x86/boot/x86_64.S b/xen/arch/x86/boot/x86_64.S
index 11a7e9d3bd..9705d03f84 100644
--- a/xen/arch/x86/boot/x86_64.S
+++ b/xen/arch/x86/boot/x86_64.S
@@ -53,17 +53,21 @@ ENTRY(__high_start)
         mov     %rcx, STACK_CPUINFO_FIELD(cr4)(%r15)
         mov     %rcx, %cr4
 
-        /* WARNING! call/ret now fatal (iff SHSTK) until SETSSBSY loads SSP */
+        /* WARNING! CALL/RET now fatal (iff SHSTK) until SETSSBSY/RSTORSSP loads SSP */
 
 #if defined(CONFIG_XEN_SHSTK)
         test    $CET_SHSTK_EN, %al
         jz      .L_ap_cet_done
 
-        /* Derive the supervisor token address from %rsp. */
+        /* Derive the token address from %rsp. */
         mov     %rsp, %rdx
         and     $~(STACK_SIZE - 1), %rdx
         or      $(PRIMARY_SHSTK_SLOT + 1) * PAGE_SIZE - 8, %rdx
 
+        /* Establishing SSP differs between IDT or FRED mode. */
+        bt      $32 /* ilog2(X86_CR4_FRED) */, %rcx
+        jc      .L_fred_shstk
+
         /*
          * Write a new Supervisor Token.  It doesn't matter the first time a
          * CPU boots, but for S3 resume or hotplug this clears the busy bit so
@@ -71,6 +75,21 @@ ENTRY(__high_start)
          */
         wrssq   %rdx, (%rdx)
         setssbsy
+        jmp     .L_ap_cet_done
+
+.L_fred_shstk:
+
+        /*
+         * Write a Restore Token, value: &token + 8 + 64BIT (bit 0) at the
+         * base of the shstk (which isn't in use yet).
+         */
+        lea     9(%rdx), %rdi
+        wrssq   %rdi, (%rdx)
+        rstorssp (%rdx)
+
+        /* Discard the Previous-SSP Token from the shstk. */
+        mov     $2, %edx
+        incsspd %edx
 
 #endif /* CONFIG_XEN_SHSTK */
 .L_ap_cet_done:
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 872a8c63f9..44da5efa1d 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -49,6 +49,7 @@
 #include <asm/prot-key.h>
 #include <asm/pv/domain.h>
 #include <asm/setup.h>
+#include <asm/shstk.h>
 #include <asm/smp.h>
 #include <asm/spec_ctrl.h>
 #include <asm/stubs.h>
@@ -908,7 +909,29 @@ static void __init noreturn reinit_bsp_stack(void)
     if ( cpu_has_xen_shstk )
     {
         wrmsrl(MSR_S_CET, xen_msr_s_cet_value());
-        asm volatile ("setssbsy" ::: "memory");
+
+        /*
+         * IDT and FRED differ by a Supervisor Token on the shadow stack.
+         *
+         * In IDT mode, we use SETSSBSY (itself using MSR_PL0_SSP, configured
+         * previously) to mark the Supervisor Token as Busy.  In FRED mode,
+         * there is no token, so we need to create a temporary Restore Token
+         * to establish SSP.
+         */
+        if ( opt_fred )
+        {
+            unsigned long *token =
+                (void *)stack + (PRIMARY_SHSTK_SLOT + 1) * PAGE_SIZE - 8;
+
+            wrss((unsigned long)token + 9, token);
+            asm volatile ( "rstorssp %0" : "+m" (*token) );
+            /*
+             * We need to discard the resulting Previous-SSP Token, but
+             * reset_stack_and_jump() will do that for us.
+             */
+        }
+        else
+            asm volatile ( "setssbsy" ::: "memory" );
     }
 
     reset_stack_and_jump(init_done);