From fc91da88d3cc7493562ad8dc50ed56f9f0177565 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Wed, 16 Sep 2009 13:15:30 +0300 Subject: test: optimize smp_id() Rather than reading it from the APIC, read it from the per-cpu area. Signed-off-by: Avi Kivity --- kvm/user/test/lib/x86/smp.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'kvm') diff --git a/kvm/user/test/lib/x86/smp.c b/kvm/user/test/lib/x86/smp.c index 25f0cae03..9eface511 100644 --- a/kvm/user/test/lib/x86/smp.c +++ b/kvm/user/test/lib/x86/smp.c @@ -71,13 +71,21 @@ int cpu_count(void) int smp_id(void) { - return apic_read(APIC_ID); + unsigned id; + + asm ("mov %%gs:0, %0" : "=r"(id)); + return id; +} + +static void setup_smp_id(void *data) +{ + asm ("mov %0, %%gs:0" : : "r"(apic_id()) : "memory"); } void on_cpu(int cpu, void (*function)(void *data), void *data) { spin_lock(&ipi_lock); - if (cpu == apic_id()) + if (cpu == smp_id()) function(data); else { ipi_function = function; @@ -98,4 +106,9 @@ void smp_init(void) void ipi_entry(void); set_ipi_descriptor(ipi_entry); + + setup_smp_id(0); + for (i = 1; i < cpu_count(); ++i) + on_cpu(i, setup_smp_id, 0); + } -- cgit v1.2.3-65-gdbad