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Diffstat (limited to 'arch/x86/xen/enlighten_pv.c')
-rw-r--r--arch/x86/xen/enlighten_pv.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ace2eb054053..9ba53814ed6a 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -219,13 +219,21 @@ static __read_mostly unsigned int cpuid_leaf5_edx_val;
static void xen_cpuid(unsigned int *ax, unsigned int *bx,
unsigned int *cx, unsigned int *dx)
{
- unsigned maskebx = ~0;
+ unsigned int maskebx = ~0;
+ unsigned int or_ebx = 0;
/*
* Mask out inconvenient features, to try and disable as many
* unsupported kernel subsystems as possible.
*/
switch (*ax) {
+ case 0x1:
+ /* Replace initial APIC ID in bits 24-31 of EBX. */
+ /* See xen_pv_smp_config() for related topology preparations. */
+ maskebx = 0x00ffffff;
+ or_ebx = smp_processor_id() << 24;
+ break;
+
case CPUID_MWAIT_LEAF:
/* Synthesize the values.. */
*ax = 0;
@@ -248,6 +256,7 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
: "0" (*ax), "2" (*cx));
*bx &= maskebx;
+ *bx |= or_ebx;
}
static bool __init xen_check_mwait(void)