Hi Paolo, We noticed the below kernel BUG on git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue commit 93c4adc7afedf9b0ec190066d45b6d67db5270da ("KVM: x86: handle missing MPX in nested virtualization") [ 17.665744] Freeing initrd memory: 213444K (ffff880072f82000 - ffff88007fff3000) [ 17.674933] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 17.682659] software IO TLB [mem 0xb73c7000-0xbb3c7000] (64MB) mapped at [ffff8800b73c7000-ffff8800bb3c6fff] [ 17.695661] BUG: unable to handle kernel NULL pointer dereference at 00000000000002b0 [ 17.705465] IP: [<ffffffff81015a9f>] kvm_arch_init+0x12a/0x1ea [ 17.712577] PGD 0 [ 17.715390] Oops: 0000 [#1] SMP [ 17.719654] Modules linked in: [ 17.723641] CPU: 10 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc7-03020-ga929a7d #1 [ 17.733067] Hardware name: Intel Corporation LH Pass/S4600LH...., BIOS SE5C600.86B.99.02.1047.032320122259 03/23/2012 [ 17.745821] task: ffff880429cb0000 ti: ffff880429ca4000 task.ti: ffff880429ca4000 [ 17.755039] RIP: 0010:[<ffffffff81015a9f>] [<ffffffff81015a9f>] kvm_arch_init+0x12a/0x1ea [ 17.765228] RSP: 0000:ffff880429ca5e00 EFLAGS: 00010246 [ 17.771644] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 17.780096] RDX: 0000000000000000 RSI: ffff880429ca5e04 RDI: 0000000000000d90 [ 17.788549] RBP: ffff880429ca5e30 R08: ffff88082fc55d00 R09: ffff88042f803e00 [ 17.796993] R10: 0000000000000004 R11: 0000000000000003 R12: 000000000000000c [ 17.805449] R13: 0000000000000017 R14: ffffffff82018b10 R15: 0000000000000018 [ 17.813907] FS: 0000000000000000(0000) GS:ffff88082fc40000(0000) knlGS:0000000000000000 [ 17.823808] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 17.830693] CR2: 00000000000002b0 CR3: 000000000200f000 CR4: 00000000000407e0 [ 17.839159] Stack: [ 17.841873] 0000000000000000 0000000000000040 0000000000000000 0000000000003f40 [ 17.851328] 0000000000000000 0000000000000000 ffff880429ca5e68 ffffffff810039dc [ 17.860790] 00000000000164d8 0000000000000006 0000000000000000 000000000000023c [ 17.870256] Call Trace: [ 17.873468] [<ffffffff810039dc>] kvm_init+0x1f/0x24a [ 17.879599] [<ffffffff82154fa4>] vmx_init+0x1df/0x3f6 [ 17.885825] [<ffffffff82154dc5>] ? vmx_check_processor_compat+0x61/0x61 [ 17.893782] [<ffffffff810002d2>] do_one_initcall+0xa4/0x13a [ 17.900604] [<ffffffff810f9aa9>] ? parse_args+0x25f/0x33d [ 17.907225] [<ffffffff8214ff94>] kernel_init_freeable+0x1a9/0x22e [ 17.914615] [<ffffffff8214f78f>] ? do_early_param+0x88/0x88 [ 17.921433] [<ffffffff819af0d5>] ? rest_init+0x89/0x89 [ 17.927731] [<ffffffff819af0e3>] kernel_init+0xe/0xdf Full dmesg is attached, and more details can be provided on your request. Thanks, Fengguang