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Commit c06ee78d authored by Mukesh Rathor's avatar Mukesh Rathor Committed by Jeremy Fitzhardinge
Browse files

xen: support large numbers of CPUs with vcpu info placement 



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: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
parent 8a22b999

arch/x86/xen/enlighten.c

+17 −4
Original line number Diff line number Diff line
@@ -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);



	if (cpu < MAX_VIRT_CPUS)

		per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];



	if (!have_vcpu_info_placement)

		return;		/* already tested, not available */

	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. */