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Commit 900cba88 authored by Andrew Jones's avatar Andrew Jones Committed by Konrad Rzeszutek Wilk
Browse files

xen: support CONFIG_MAXSMP 



The MAXSMP config option requires CPUMASK_OFFSTACK, which in turn
requires we init the memory for the maps while we bring up the cpus.
MAXSMP also increases NR_CPUS to 4096. This increase in size exposed an
issue in the argument construction for multicalls from
xen_flush_tlb_others. The args should only need space for the actual
number of cpus.

Also in 2.6.39 it exposes a bootup problem.

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff8157a1d3>] set_cpu_sibling_map+0x123/0x30d
...
Call Trace:
[<ffffffff81039a3f>] ? xen_restore_fl_direct_reloc+0x4/0x4
[<ffffffff819dc4db>] xen_smp_prepare_cpus+0x36/0x135
..

CC: stable@kernel.org
Signed-off-by: default avatarAndrew Jones <drjones@redhat.com>
[v2: Updated to compile on 3.0]
[v3: Updated to compile when CONFIG_SMP is not defined]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent a91d9287

arch/x86/xen/mmu.c

+2 −1
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ 
#include <asm/page.h>

#include <asm/init.h>

#include <asm/pat.h>

#include <asm/smp.h>



#include <asm/xen/hypercall.h>

#include <asm/xen/hypervisor.h>
@@ -1231,7 +1232,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, 
{

	struct {

		struct mmuext_op op;

		DECLARE_BITMAP(mask, NR_CPUS);

		DECLARE_BITMAP(mask, num_processors);

	} *args;

	struct multicall_space mcs;

arch/x86/xen/smp.c

+7 −0
Original line number Diff line number Diff line
@@ -205,11 +205,18 @@ static void __init xen_smp_prepare_boot_cpu(void) 
static void __init xen_smp_prepare_cpus(unsigned int max_cpus)

{

	unsigned cpu;

	unsigned int i;



	xen_init_lock_cpu(0);



	smp_store_cpu_info(0);

	cpu_data(0).x86_max_cores = 1;



	for_each_possible_cpu(i) {

		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);

		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);

		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);

	}

	set_cpu_sibling_map(0);



	if (xen_smp_intr_init(0))