[PATCH] x86/CPU/AMD: avoid printing reset reasons on Xen domU

[Ariadne Conill <ariadne@ariadne.space>]

Xen domU cannot access the given MMIO address for security reasons,
resulting in a failed hypercall in ioremap() due to permissions.

Fixes: ab8131028710 ("x86/CPU/AMD: Print the reason for the last reset")
Signed-off-by: Ariadne Conill <ariadne@ariadne.space>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
---
 arch/x86/kernel/cpu/amd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index a6f88ca1a6b4..99308fba4d7d 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -29,6 +29,8 @@
 # include <asm/mmconfig.h>
 #endif
 
+#include <xen/xen.h>
+
 #include "cpu.h"
 
 u16 invlpgb_count_max __ro_after_init = 1;
@@ -1333,6 +1335,10 @@ static __init int print_s5_reset_status_mmio(void)
        if (!cpu_feature_enabled(X86_FEATURE_ZEN))
                return 0;
 
+       /* Xen PV domU cannot access hardware directly, so bail for domU case */
+       if (cpu_feature_enabled(X86_FEATURE_XENPV) && !xen_initial_domain())
+               return 0;
+
        addr = ioremap(FCH_PM_BASE + FCH_PM_S5_RESET_STATUS, sizeof(value));
        if (!addr)
                return 0;
-- 
2.51.0