From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Piggin Date: Fri, 06 Apr 2018 04:14:09 +0000 Subject: [RFC PATCH] KVM: PPC: Book3S HV: send kvmppc_bad_interrupt NMIs to Linux handlers Message-Id: <20180406041409.8353-1-npiggin@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org It's possible to take a SRESET or MCE in these paths due to a bug in the host code or a NMI IPI etc. A recent bug attempting to load a virtual address gave a complete but cryptic error, abridged: Oops: Bad interrupt in KVM entry/exit code, sig: 6 [#1] LE SMP NR_CPUS 48 NUMA PowerNV CPU: 53 PID: 6582 Comm: qemu-system-ppc Not tainted NIP: c0000000000155ac LR: c0000000000c2430 CTR: c000000000015580 REGS: c000000fff76dd80 TRAP: 0200 Not tainted MSR: 9000000000201003 CR: 48082222 XER: 00000000 CFAR: 0000000102900ef0 DAR: d00017fffd941a28 DSISR: 00000040 SOFTE: 3 NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0 LR [c0000000000c2430] do_tlbies+0x230/0x2f0 Sending NMIs through the Linux handlers gives a nicer output: Severe Machine check interrupt [Not recovered] NIP [c0000000000155ac]: perf_trace_tlbie+0x2c/0x1a0 Initiator: CPU Error type: Real address [Load (bad)] Effective address: d00017fffcc01a28 opal: Machine check interrupt unrecoverable: MSR(RI=0) opal: Hardware platform error: Unrecoverable Machine Check exception CPU: 0 PID: 6700 Comm: qemu-system-ppc Tainted: G M NIP: c0000000000155ac LR: c0000000000c23c0 CTR: c000000000015580 REGS: c000000fff9e9d80 TRAP: 0200 Tainted: G M MSR: 9000000000201001 CR: 48082222 XER: 00000000 CFAR: 000000010cbc1a30 DAR: d00017fffcc01a28 DSISR: 00000040 SOFTE: 3 NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0 LR [c0000000000c23c0] do_tlbies+0x1c0/0x280 Signed-off-by: Nicholas Piggin --- This is lightly tested only, not sure if there would be a better way to do it? arch/powerpc/kvm/book3s_hv_builtin.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c index de18299f92b7..0b9b8e188bfa 100644 --- a/arch/powerpc/kvm/book3s_hv_builtin.c +++ b/arch/powerpc/kvm/book3s_hv_builtin.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -633,6 +634,17 @@ int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr) void kvmppc_bad_interrupt(struct pt_regs *regs) { + regs->msr &= ~MSR_RI; + /* + * 100 could happen at any time, 200 can happen due to + * invalid real address access for example. + */ + if (TRAP(regs) = 0x100) { + get_paca()->in_nmi++; + system_reset_exception(regs); + } + if (TRAP(regs) = 0x200) + machine_check_exception(regs); die("Bad interrupt in KVM entry/exit code", regs, SIGABRT); panic("Bad KVM trap"); } -- 2.16.3