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xen: support large numbers of CPUs with vcpu info placement

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When vcpu info placement is supported, we're not limited to MAX_VIRT_CPUS
vcpus.  However, if it isn't supported, then ignore any excess vcpus.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Mukesh Rathor 2010-07-19 10:25:08 -07:00 committed by Jeremy Fitzhardinge
parent 8a22b9996b
commit c06ee78d73
1 changed files with 17 additions and 4 deletions
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21
arch/x86/xen/enlighten.c
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@ -97,6 +97,14 @@ struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
*/
static int have_vcpu_info_placement = 1;
static void clamp_max_cpus(void)
{
#ifdef CONFIG_SMP
if (setup_max_cpus > MAX_VIRT_CPUS)
setup_max_cpus = MAX_VIRT_CPUS;
#endif
}
static void xen_vcpu_setup(int cpu)
{
struct vcpu_register_vcpu_info info;
@ -104,13 +112,17 @@ static void xen_vcpu_setup(int cpu)
struct vcpu_info *vcpup;
BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
if (!have_vcpu_info_placement)
return; /* already tested, not available */
if (cpu < MAX_VIRT_CPUS)
per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
if (!have_vcpu_info_placement) {
if (cpu >= MAX_VIRT_CPUS)
clamp_max_cpus();
return;
}
vcpup = &per_cpu(xen_vcpu_info, cpu);
info.mfn = arbitrary_virt_to_mfn(vcpup);
info.offset = offset_in_page(vcpup);
@ -125,6 +137,7 @@ static void xen_vcpu_setup(int cpu)
if (err) {
printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
have_vcpu_info_placement = 0;
clamp_max_cpus();
} else {
/* This cpu is using the registered vcpu info, even if
later ones fail to. */