From 5cffb77c4072fa5b46700a2dbb3e46c5a54eba6d Mon Sep 17 00:00:00 2001 From: Aravindh Puthiyaparambil Date: Mon, 3 Jun 2013 15:42:46 +0200 Subject: [PATCH] x86/MCE: disable if MCE banks are not present When booting Xen on VMware ESX 5.1 and Workstation 9, you hit a GPF during MCE initialization. The culprit is line 631 in set_poll_bankmask(): bitmap_copy(mb->bank_map, mca_allbanks->bank_map, nr_mce_banks); What is happening is that in mca_cap_init(), nr_mce_banks is being set to 0. This causes the allocation of bank_map to be set to ZERO_BLOCK_PTR which is the return value for zero-size allocation by xzalloc_array()/_xmalloc(). This results in the bitmap_copy() to fail disastrously. The following patch fixes this issue. Signed-off-by: Aravindh Puthiyaparambil Reviewed-by: Andrew Cooper Acked-by: Christoph Egger --- xen/arch/x86/cpu/mcheck/mce.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c index 6712db1df9..93d7ae1647 100644 --- a/xen/arch/x86/cpu/mcheck/mce.c +++ b/xen/arch/x86/cpu/mcheck/mce.c @@ -652,7 +652,14 @@ int mca_cap_init(void) } nr_mce_banks = msr_content & MCG_CAP_COUNT; - /* mcabanks_alloc depends on nr_mcebanks */ + if (!nr_mce_banks) + { + printk(XENLOG_INFO "CPU%u: No MCE banks present. " + "Machine check support disabled\n", smp_processor_id()); + return -ENODEV; + } + + /* mcabanks_alloc depends on nr_mce_banks */ if (!mca_allbanks) { int i; -- 2.39.5