diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h
index 009bca514c20..110a73e0572d 100644
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -29,14 +29,19 @@ orq  X86_CR3_PCID_KERN_VAR, \reg
 movq \reg, %cr3
 .endm
 
-.macro _SWITCH_TO_USER_CR3 reg
+.macro _SWITCH_TO_USER_CR3 reg regb
+/*
+ * regb must be the low byte portion of reg: because we have arranged
+ * for the low byte of the user PCID to serve as the high byte of NOFLUSH
+ * (0x80 for each when PCID is enabled, or 0x00 when PCID and NOFLUSH are
+ * not enabled): so that the one register can update both memory and cr3.
+ */
 movq %cr3, \reg
 andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
 orq  PER_CPU_VAR(X86_CR3_PCID_USER_VAR), \reg
 js   9f
-// FLUSH this time, reset to NOFLUSH for next time
-// But if nopcid?  Consider using 0x80 for user pcid?
-movb $(0x80), PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
+/* FLUSH this time, reset to NOFLUSH for next time (if PCID enabled) */
+movb \regb, PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
 9:
 movq \reg, %cr3
 .endm
@@ -49,7 +54,7 @@ popq %rax
 
 .macro SWITCH_USER_CR3
 pushq %rax
-_SWITCH_TO_USER_CR3 %rax
+_SWITCH_TO_USER_CR3 %rax %al
 popq %rax
 .endm
 
@@ -61,7 +66,7 @@ movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
 
 .macro SWITCH_USER_CR3_NO_STACK
 movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
-_SWITCH_TO_USER_CR3 %rax
+_SWITCH_TO_USER_CR3 %rax %al
 movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
 .endm
 
@@ -69,7 +74,7 @@ movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
 
 .macro SWITCH_KERNEL_CR3 reg
 .endm
-.macro SWITCH_USER_CR3 reg
+.macro SWITCH_USER_CR3 reg regb
 .endm
 .macro SWITCH_USER_CR3_NO_STACK
 .endm
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 79319174e27b..22704eca1900 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -111,16 +111,17 @@
 
 /* Mask for all the PCID-related bits in CR3: */
 #define X86_CR3_PCID_MASK       (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_MASK)
+#define X86_CR3_PCID_ASID_KERN  (_AC(0x0,UL))
+
 #if defined(CONFIG_KAISER) && defined(CONFIG_X86_64)
-#define X86_CR3_PCID_ASID_KERN  (_AC(0x4,UL))
-#define X86_CR3_PCID_ASID_USER  (_AC(0x6,UL))
+/* Let X86_CR3_PCID_ASID_USER be usable for the X86_CR3_PCID_NOFLUSH bit */
+#define X86_CR3_PCID_ASID_USER	(_AC(0x80,UL))
 
 #define X86_CR3_PCID_KERN_FLUSH		(X86_CR3_PCID_ASID_KERN)
 #define X86_CR3_PCID_USER_FLUSH		(X86_CR3_PCID_ASID_USER)
 #define X86_CR3_PCID_KERN_NOFLUSH	(X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_KERN)
 #define X86_CR3_PCID_USER_NOFLUSH	(X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_USER)
 #else
-#define X86_CR3_PCID_ASID_KERN  (_AC(0x0,UL))
 #define X86_CR3_PCID_ASID_USER  (_AC(0x0,UL))
 /*
  * PCIDs are unsupported on 32-bit and none of these bits can be
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 99a5d1b95527..90ef67a9e34b 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -50,6 +50,9 @@ static void load_new_mm_cr3(pgd_t *pgdir)
 		 * invpcid_flush_single_context(X86_CR3_PCID_ASID_USER) could
 		 * do it here, but can only be used if X86_FEATURE_INVPCID is
 		 * available - and many machines support pcid without invpcid.
+		 *
+		 * The line below is a no-op: X86_CR3_PCID_KERN_FLUSH is now 0;
+		 * but keep that line in there in case something changes.
 		 */
 		new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH;
 		kaiser_flush_tlb_on_return_to_user();