diff options
authorTom Lendacky <>2017-11-06 14:17:53 -0600
committerThomas Gleixner <>2017-11-17 15:30:33 +0100
commitac5292e9a294618cecb31109d1ba265e3d027ba2 (patch)
parentbe62a32044061cb4a3b70a10598e093f1319102e (diff)
x86/boot: Fix boot failure when SMP MP-table is based at 0
When crosvm is used to boot a kernel as a VM, the SMP MP-table is found at physical address 0x0. This causes mpf_base to be set to 0 and a subsequent "if (!mpf_base)" check in default_get_smp_config() results in the MP-table not being parsed. Further into the boot this results in an oops when attempting a read_apic_id(). Add a boolean variable that is set to true when the MP-table is found. Use this variable for testing if the MP-table was found so that even a value of 0 for mpf_base will result in continued parsing of the MP-table. Fixes: 5997efb96756 ("x86/boot: Use memremap() to map the MPF and MPC data") Reported-by: Tomeu Vizoso <> Signed-off-by: Tom Lendacky <> Signed-off-by: Thomas Gleixner <> Cc: Peter Zijlstra <> Cc: Borislav Petkov <> Cc: Cc: Link:
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index 410c5dadcee3..3a4b12809ab5 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -431,6 +431,7 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
static unsigned long mpf_base;
+static bool mpf_found;
static unsigned long __init get_mpc_size(unsigned long physptr)
@@ -504,7 +505,7 @@ void __init default_get_smp_config(unsigned int early)
if (!smp_found_config)
- if (!mpf_base)
+ if (!mpf_found)
if (acpi_lapic && early)
@@ -593,6 +594,7 @@ static int __init smp_scan_config(unsigned long base, unsigned long length)
smp_found_config = 1;
mpf_base = base;
+ mpf_found = true;
pr_info("found SMP MP-table at [mem %#010lx-%#010lx] mapped at [%p]\n",
base, base + sizeof(*mpf) - 1, mpf);
@@ -858,7 +860,7 @@ static int __init update_mp_table(void)
if (!enable_update_mptable)
return 0;
- if (!mpf_base)
+ if (!mpf_found)
return 0;
mpf = early_memremap(mpf_base, sizeof(*mpf));