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xen: initialize cpu masks for pv guests in xen_smp_init

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Pv guests don't have ACPI and need the cpu masks to be set
correctly as early as possible so we call xen_fill_possible_map from
xen_smp_init.
On the other hand the initial domain supports ACPI so in this case we skip
xen_fill_possible_map and rely on it. However Xen might limit the number
of cpus usable by the domain, so we filter those masks during smp
initialization using the VCPUOP_is_up hypercall.
It is important that the filtering is done before
xen_setup_vcpu_info_placement.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Stefano Stabellini 2010-10-26 17:28:33 +01:00
parent 0e058e5277
commit ea5b8f7393
1 changed files with 22 additions and 2 deletions
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24
arch/x86/xen/smp.c
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@ -28,6 +28,7 @@
#include <asm/xen/interface.h>
#include <asm/xen/hypercall.h>
#include <xen/xen.h>
#include <xen/page.h>
#include <xen/events.h>
@ -156,6 +157,25 @@ static void __init xen_fill_possible_map(void)
{
int i, rc;
if (xen_initial_domain())
return;
for (i = 0; i < nr_cpu_ids; i++) {
rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
if (rc >= 0) {
num_processors++;
set_cpu_possible(i, true);
}
}
}
static void __init xen_filter_cpu_maps(void)
{
int i, rc;
if (!xen_initial_domain())
return;
num_processors = 0;
disabled_cpus = 0;
for (i = 0; i < nr_cpu_ids; i++) {
@ -179,6 +199,7 @@ static void __init xen_smp_prepare_boot_cpu(void)
old memory can be recycled */
make_lowmem_page_readwrite(xen_initial_gdt);
xen_filter_cpu_maps();
xen_setup_vcpu_info_placement();
}
@ -195,8 +216,6 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
if (xen_smp_intr_init(0))
BUG();
xen_fill_possible_map();
if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
panic("could not allocate xen_cpu_initialized_map\n");
@ -487,5 +506,6 @@ static const struct smp_ops xen_smp_ops __initdata = {
void __init xen_smp_init(void)
{
smp_ops = xen_smp_ops;
xen_fill_possible_map();
xen_init_spinlocks();
}