Commits
Wanpeng Li committed 910053002ef
KVM: lapic: fix access preemption timer stuff even if kernel_irqchip=off BUG: unable to handle kernel NULL pointer dereference at 000000000000008c IP: [<ffffffffc04e0180>] kvm_lapic_hv_timer_in_use+0x10/0x20 [kvm] PGD 0 Oops: 0000 [#1] SMP Call Trace: kvm_arch_vcpu_load+0x86/0x260 [kvm] vcpu_load+0x46/0x60 [kvm] kvm_vcpu_ioctl+0x79/0x7c0 [kvm] ? __lock_is_held+0x54/0x70 do_vfs_ioctl+0x96/0x6a0 ? __fget_light+0x2a/0x90 SyS_ioctl+0x79/0x90 do_syscall_64+0x7c/0x1e0 entry_SYSCALL64_slow_path+0x25/0x25 RIP [<ffffffffc04e0180>] kvm_lapic_hv_timer_in_use+0x10/0x20 [kvm] RSP <ffff8800db1f3d70> CR2: 000000000000008c ---[ end trace a55fb79d2b3b4ee8 ]--- This can be reproduced steadily by kernel_irqchip=off. We should not access preemption timer stuff if lapic is emulated in userspace. This patch fix it by avoiding access preemption timer stuff when kernel_irqchip=off. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Yunhong Jiang <yunhong.jiang@intel.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>