[PATCH v4 3/4] xen: arm: Enclose access to EL2 MMU specific registers under CONFIG_MMU

[Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>]

All the EL2 MMU specific registers are enclosed within CONFIG_MMU.
Also, protect vttbr_el2 field of struct reg_ctxt and accesses to it.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
Changes from :

v1 -
1. 'vttbr_el2' field is enclosed with ifdef.
2. No movement of code.

v2 -
1. Enclosed 'vttbr_el2' access in show_registers() and vcpu_show_registers().

v3 -
1. Updated the commit message.
2. Added R-b.

 xen/arch/arm/traps.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index aac6c599f8..737f4d65e3 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -720,8 +720,10 @@ struct reg_ctxt {
     uint32_t ifsr32_el2;
 #endif
 
+#ifdef CONFIG_MMU
     /* Hypervisor-side state */
     uint64_t vttbr_el2;
+#endif
 };
 
 static const char *mode_string(register_t cpsr)
@@ -919,12 +921,16 @@ static void _show_registers(const struct cpu_user_regs 
*regs,
 #endif
     }
     printk("  VTCR_EL2: %"PRIregister"\n", READ_SYSREG(VTCR_EL2));
+#ifdef CONFIG_MMU
     printk(" VTTBR_EL2: %016"PRIx64"\n", ctxt->vttbr_el2);
+#endif
     printk("\n");
 
     printk(" SCTLR_EL2: %"PRIregister"\n", READ_SYSREG(SCTLR_EL2));
     printk("   HCR_EL2: %"PRIregister"\n", READ_SYSREG(HCR_EL2));
+#ifdef CONFIG_MMU
     printk(" TTBR0_EL2: %016"PRIx64"\n", READ_SYSREG64(TTBR0_EL2));
+#endif
     printk("\n");
     printk("   ESR_EL2: %"PRIregister"\n", regs->hsr);
     printk(" HPFAR_EL2: %"PRIregister"\n", READ_SYSREG(HPFAR_EL2));
@@ -956,7 +962,9 @@ void show_registers(const struct cpu_user_regs *regs)
     if ( guest_mode(regs) && is_32bit_domain(current->domain) )
         ctxt.ifsr32_el2 = READ_SYSREG(IFSR32_EL2);
 #endif
+#ifdef CONFIG_MMU
     ctxt.vttbr_el2 = READ_SYSREG64(VTTBR_EL2);
+#endif
 
     _show_registers(regs, &ctxt, guest_mode(regs), current);
 }
@@ -979,7 +987,9 @@ void vcpu_show_registers(const struct vcpu *v)
     ctxt.ifsr32_el2 = v->arch.ifsr;
 #endif
 
+#ifdef CONFIG_MMU
     ctxt.vttbr_el2 = v->domain->arch.p2m.vttbr;
+#endif
 
     _show_registers(&v->arch.cpu_info->guest_cpu_user_regs, &ctxt, 1, v);
 }
-- 
2.25.1