From 25970852280c9d5fb2de899769880d3e97332baa Mon Sep 17 00:00:00 2001 From: Naga Chumbalkar Date: Tue, 12 Jul 2011 05:59:07 +0000 Subject: [PATCH] x86, x2apic: Preserve high 32-bits of IA32_APIC_BASE MSR If there's no special reason to zero-out the "high" 32-bits of the IA32_APIC_BASE MSR, let's preserve it. The x2APIC Specification doesn't explicitly state any such requirement. (Sec 2.2 in: http://www.intel.com/Assets/PDF/manual/318148.pdf). Signed-off-by: Naga Chumbalkar Link: http://lkml.kernel.org/r/20110712055831.2498.78521.sendpatchset@nchumbalkar.americas.cpqcorp.net Reviewed-by: Cyrill Gorcunov Reviewed-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/kernel/apic/apic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b9338b8cf420..f7b0c7a1dfaa 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1429,7 +1429,7 @@ void enable_x2apic(void) rdmsr(MSR_IA32_APICBASE, msr, msr2); if (!(msr & X2APIC_ENABLE)) { printk_once(KERN_INFO "Enabling x2apic\n"); - wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, 0); + wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, msr2); } } #endif /* CONFIG_X86_X2APIC */ -- GitLab