From 7562c4fded33ca931e17f30a259f49ac20c89b7d Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sun, 4 May 2014 22:56:08 +0530 Subject: [PATCH] KVM: PPC: BOOK3S: PR: Fix WARN_ON with debug options on With debug option "sleep inside atomic section checking" enabled we get the below WARN_ON during a PR KVM boot. This is because upstream now have PREEMPT_COUNT enabled even if we have preempt disabled. Fix the warning by adding preempt_disable/enable around floating point and altivec enable. WARNING: at arch/powerpc/kernel/process.c:156 Modules linked in: kvm_pr kvm CPU: 1 PID: 3990 Comm: qemu-system-ppc Tainted: G W 3.15.0-rc1+ #4 task: c0000000eb85b3a0 ti: c0000000ec59c000 task.ti: c0000000ec59c000 NIP: c000000000015c84 LR: d000000003334644 CTR: c000000000015c00 REGS: c0000000ec59f140 TRAP: 0700 Tainted: G W (3.15.0-rc1+) MSR: 8000000000029032 CR: 42000024 XER: 20000000 CFAR: c000000000015c24 SOFTE: 1 GPR00: d000000003334644 c0000000ec59f3c0 c000000000e2fa40 c0000000e2f80000 GPR04: 0000000000000800 0000000000002000 0000000000000001 8000000000000000 GPR08: 0000000000000001 0000000000000001 0000000000002000 c000000000015c00 GPR12: d00000000333da18 c00000000fb80900 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 00003fffce4e0fa1 GPR20: 0000000000000010 0000000000000001 0000000000000002 00000000100b9a38 GPR24: 0000000000000002 0000000000000000 0000000000000000 0000000000000013 GPR28: 0000000000000000 c0000000eb85b3a0 0000000000002000 c0000000e2f80000 NIP [c000000000015c84] .enable_kernel_fp+0x84/0x90 LR [d000000003334644] .kvmppc_handle_ext+0x134/0x190 [kvm_pr] Call Trace: [c0000000ec59f3c0] [0000000000000010] 0x10 (unreliable) [c0000000ec59f430] [d000000003334644] .kvmppc_handle_ext+0x134/0x190 [kvm_pr] [c0000000ec59f4c0] [d00000000324b380] .kvmppc_set_msr+0x30/0x50 [kvm] [c0000000ec59f530] [d000000003337cac] .kvmppc_core_emulate_op_pr+0x16c/0x5e0 [kvm_pr] [c0000000ec59f5f0] [d00000000324a944] .kvmppc_emulate_instruction+0x284/0xa80 [kvm] [c0000000ec59f6c0] [d000000003336888] .kvmppc_handle_exit_pr+0x488/0xb70 [kvm_pr] [c0000000ec59f790] [d000000003338d34] kvm_start_lightweight+0xcc/0xdc [kvm_pr] [c0000000ec59f960] [d000000003336288] .kvmppc_vcpu_run_pr+0xc8/0x190 [kvm_pr] [c0000000ec59f9f0] [d00000000324c880] .kvmppc_vcpu_run+0x30/0x50 [kvm] [c0000000ec59fa60] [d000000003249e74] .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [kvm] [c0000000ec59faf0] [d000000003244948] .kvm_vcpu_ioctl+0x478/0x760 [kvm] [c0000000ec59fcb0] [c000000000224e34] .do_vfs_ioctl+0x4d4/0x790 [c0000000ec59fd90] [c000000000225148] .SyS_ioctl+0x58/0xb0 [c0000000ec59fe30] [c00000000000a1e4] syscall_exit+0x0/0x98 Signed-off-by: Aneesh Kumar K.V Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_pr.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 8c05cb5877a9..01a7156d055c 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -683,16 +683,20 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr, #endif if (msr & MSR_FP) { + preempt_disable(); enable_kernel_fp(); load_fp_state(&vcpu->arch.fp); t->fp_save_area = &vcpu->arch.fp; + preempt_enable(); } if (msr & MSR_VEC) { #ifdef CONFIG_ALTIVEC + preempt_disable(); enable_kernel_altivec(); load_vr_state(&vcpu->arch.vr); t->vr_save_area = &vcpu->arch.vr; + preempt_enable(); #endif } @@ -716,13 +720,17 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu) return; if (lost_ext & MSR_FP) { + preempt_disable(); enable_kernel_fp(); load_fp_state(&vcpu->arch.fp); + preempt_enable(); } #ifdef CONFIG_ALTIVEC if (lost_ext & MSR_VEC) { + preempt_disable(); enable_kernel_altivec(); load_vr_state(&vcpu->arch.vr); + preempt_enable(); } #endif current->thread.regs->msr |= lost_ext; -- 2.45.2