From: James Hogan <james.hogan@imgtec.com> To: <linux-mips@linux-mips.org>, <kvm@vger.kernel.org> Cc: "James Hogan" <james.hogan@imgtec.com>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, "Steven Rostedt" <rostedt@goodmis.org>, "Ingo Molnar" <mingo@redhat.com>, "Ralf Baechle" <ralf@linux-mips.org> Subject: [PATCH v2 33/33] KVM: MIPS/VZ: Trace guest mode changes Date: Tue, 14 Mar 2017 10:15:40 +0000 [thread overview] Message-ID: <4eda0cc8497852c142a05f9fd37ea87ceecff853.1489485940.git-series.james.hogan@imgtec.com> (raw) In-Reply-To: <cover.26e10ec77a4ed0d3177ccf4fabf57bc95ea030f8.1489485940.git-series.james.hogan@imgtec.com> Create a trace event for guest mode changes, and enable VZ's GuestCtl0.MC bit after the trace event is enabled to trap all guest mode changes. The MC bit causes Guest Hardware Field Change (GHFC) exceptions whenever a guest mode change occurs (such as an exception entry or return from exception), so we need to handle this exception now. The MC bit is only enabled when restoring register state, so enabling the trace event won't take immediate effect. Tracing guest mode changes can be particularly handy when trying to work out what a guest OS gets up to before something goes wrong, especially if the problem occurs as a result of some previous guest userland exception which would otherwise be invisible in the trace. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/mips.c | 13 +++++++++++++ arch/mips/kvm/trace.h | 37 +++++++++++++++++++++++++++++++++++++ arch/mips/kvm/vz.c | 21 +++++++++++++++++++-- 3 files changed, 69 insertions(+), 2 deletions(-) diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index e8ddb128b8ad..1fc6fef463db 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -76,6 +76,19 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { {NULL} }; +bool kvm_trace_guest_mode_change; + +int kvm_guest_mode_change_trace_reg(void) +{ + kvm_trace_guest_mode_change = 1; + return 0; +} + +void kvm_guest_mode_change_trace_unreg(void) +{ + kvm_trace_guest_mode_change = 0; +} + /* * XXXKYMA: We are simulatoring a processor that has the WII bit set in * Config7, so we are "runnable" if interrupts are pending diff --git a/arch/mips/kvm/trace.h b/arch/mips/kvm/trace.h index affde8a2c584..a8c7fd7bf6d2 100644 --- a/arch/mips/kvm/trace.h +++ b/arch/mips/kvm/trace.h @@ -18,6 +18,13 @@ #define TRACE_INCLUDE_FILE trace /* + * arch/mips/kvm/mips.c + */ +extern bool kvm_trace_guest_mode_change; +int kvm_guest_mode_change_trace_reg(void); +void kvm_guest_mode_change_trace_unreg(void); + +/* * Tracepoints for VM enters */ DECLARE_EVENT_CLASS(kvm_transition, @@ -303,6 +310,36 @@ TRACE_EVENT(kvm_guestid_change, __entry->guestid) ); +TRACE_EVENT_FN(kvm_guest_mode_change, + TP_PROTO(struct kvm_vcpu *vcpu), + TP_ARGS(vcpu), + TP_STRUCT__entry( + __field(unsigned long, epc) + __field(unsigned long, pc) + __field(unsigned long, badvaddr) + __field(unsigned int, status) + __field(unsigned int, cause) + ), + + TP_fast_assign( + __entry->epc = kvm_read_c0_guest_epc(vcpu->arch.cop0); + __entry->pc = vcpu->arch.pc; + __entry->badvaddr = kvm_read_c0_guest_badvaddr(vcpu->arch.cop0); + __entry->status = kvm_read_c0_guest_status(vcpu->arch.cop0); + __entry->cause = kvm_read_c0_guest_cause(vcpu->arch.cop0); + ), + + TP_printk("EPC: 0x%08lx PC: 0x%08lx Status: 0x%08x Cause: 0x%08x BadVAddr: 0x%08lx", + __entry->epc, + __entry->pc, + __entry->status, + __entry->cause, + __entry->badvaddr), + + kvm_guest_mode_change_trace_reg, + kvm_guest_mode_change_trace_unreg +); + #endif /* _TRACE_KVM_H */ /* This part must be outside protection */ diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c index 44dad9ae5d02..33bb8c6e1b05 100644 --- a/arch/mips/kvm/vz.c +++ b/arch/mips/kvm/vz.c @@ -1322,6 +1322,18 @@ static enum emulation_result kvm_trap_vz_handle_gsfc(u32 cause, u32 *opc, return er; } +static enum emulation_result kvm_trap_vz_handle_ghfc(u32 cause, u32 *opc, + struct kvm_vcpu *vcpu) +{ + /* + * Presumably this is due to MC (guest mode change), so lets trace some + * relevant info. + */ + trace_kvm_guest_mode_change(vcpu); + + return EMULATE_DONE; +} + static enum emulation_result kvm_trap_vz_handle_hc(u32 cause, u32 *opc, struct kvm_vcpu *vcpu) { @@ -1407,8 +1419,7 @@ static int kvm_trap_vz_handle_guest_exit(struct kvm_vcpu *vcpu) break; case MIPS_GCTL0_GEXC_GHFC: ++vcpu->stat.vz_ghfc_exits; - er = kvm_trap_vz_no_handler_guest_exit(gexccode, cause, opc, - vcpu); + er = kvm_trap_vz_handle_ghfc(cause, opc, vcpu); break; case MIPS_GCTL0_GEXC_GPA: ++vcpu->stat.vz_gpa_exits; @@ -2459,6 +2470,12 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu) */ kvm_vz_restore_timer(vcpu); + /* Set MC bit if we want to trace guest mode changes */ + if (kvm_trace_guest_mode_change) + set_c0_guestctl0(MIPS_GCTL0_MC); + else + clear_c0_guestctl0(MIPS_GCTL0_MC); + /* Don't bother restoring registers multiple times unless necessary */ if (!all) return 0; -- git-series 0.8.10
WARNING: multiple messages have this Message-ID (diff)
From: James Hogan <james.hogan@imgtec.com> To: linux-mips@linux-mips.org, kvm@vger.kernel.org Cc: "James Hogan" <james.hogan@imgtec.com>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, "Steven Rostedt" <rostedt@goodmis.org>, "Ingo Molnar" <mingo@redhat.com>, "Ralf Baechle" <ralf@linux-mips.org> Subject: [PATCH v2 33/33] KVM: MIPS/VZ: Trace guest mode changes Date: Tue, 14 Mar 2017 10:15:40 +0000 [thread overview] Message-ID: <4eda0cc8497852c142a05f9fd37ea87ceecff853.1489485940.git-series.james.hogan@imgtec.com> (raw) Message-ID: <20170314101540.IqTxwKhPMhZqJj1kZ3vkvadmoOg7bSYLT7drm91XDpM@z> (raw) In-Reply-To: <cover.26e10ec77a4ed0d3177ccf4fabf57bc95ea030f8.1489485940.git-series.james.hogan@imgtec.com> Create a trace event for guest mode changes, and enable VZ's GuestCtl0.MC bit after the trace event is enabled to trap all guest mode changes. The MC bit causes Guest Hardware Field Change (GHFC) exceptions whenever a guest mode change occurs (such as an exception entry or return from exception), so we need to handle this exception now. The MC bit is only enabled when restoring register state, so enabling the trace event won't take immediate effect. Tracing guest mode changes can be particularly handy when trying to work out what a guest OS gets up to before something goes wrong, especially if the problem occurs as a result of some previous guest userland exception which would otherwise be invisible in the trace. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/mips.c | 13 +++++++++++++ arch/mips/kvm/trace.h | 37 +++++++++++++++++++++++++++++++++++++ arch/mips/kvm/vz.c | 21 +++++++++++++++++++-- 3 files changed, 69 insertions(+), 2 deletions(-) diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index e8ddb128b8ad..1fc6fef463db 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -76,6 +76,19 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { {NULL} }; +bool kvm_trace_guest_mode_change; + +int kvm_guest_mode_change_trace_reg(void) +{ + kvm_trace_guest_mode_change = 1; + return 0; +} + +void kvm_guest_mode_change_trace_unreg(void) +{ + kvm_trace_guest_mode_change = 0; +} + /* * XXXKYMA: We are simulatoring a processor that has the WII bit set in * Config7, so we are "runnable" if interrupts are pending diff --git a/arch/mips/kvm/trace.h b/arch/mips/kvm/trace.h index affde8a2c584..a8c7fd7bf6d2 100644 --- a/arch/mips/kvm/trace.h +++ b/arch/mips/kvm/trace.h @@ -18,6 +18,13 @@ #define TRACE_INCLUDE_FILE trace /* + * arch/mips/kvm/mips.c + */ +extern bool kvm_trace_guest_mode_change; +int kvm_guest_mode_change_trace_reg(void); +void kvm_guest_mode_change_trace_unreg(void); + +/* * Tracepoints for VM enters */ DECLARE_EVENT_CLASS(kvm_transition, @@ -303,6 +310,36 @@ TRACE_EVENT(kvm_guestid_change, __entry->guestid) ); +TRACE_EVENT_FN(kvm_guest_mode_change, + TP_PROTO(struct kvm_vcpu *vcpu), + TP_ARGS(vcpu), + TP_STRUCT__entry( + __field(unsigned long, epc) + __field(unsigned long, pc) + __field(unsigned long, badvaddr) + __field(unsigned int, status) + __field(unsigned int, cause) + ), + + TP_fast_assign( + __entry->epc = kvm_read_c0_guest_epc(vcpu->arch.cop0); + __entry->pc = vcpu->arch.pc; + __entry->badvaddr = kvm_read_c0_guest_badvaddr(vcpu->arch.cop0); + __entry->status = kvm_read_c0_guest_status(vcpu->arch.cop0); + __entry->cause = kvm_read_c0_guest_cause(vcpu->arch.cop0); + ), + + TP_printk("EPC: 0x%08lx PC: 0x%08lx Status: 0x%08x Cause: 0x%08x BadVAddr: 0x%08lx", + __entry->epc, + __entry->pc, + __entry->status, + __entry->cause, + __entry->badvaddr), + + kvm_guest_mode_change_trace_reg, + kvm_guest_mode_change_trace_unreg +); + #endif /* _TRACE_KVM_H */ /* This part must be outside protection */ diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c index 44dad9ae5d02..33bb8c6e1b05 100644 --- a/arch/mips/kvm/vz.c +++ b/arch/mips/kvm/vz.c @@ -1322,6 +1322,18 @@ static enum emulation_result kvm_trap_vz_handle_gsfc(u32 cause, u32 *opc, return er; } +static enum emulation_result kvm_trap_vz_handle_ghfc(u32 cause, u32 *opc, + struct kvm_vcpu *vcpu) +{ + /* + * Presumably this is due to MC (guest mode change), so lets trace some + * relevant info. + */ + trace_kvm_guest_mode_change(vcpu); + + return EMULATE_DONE; +} + static enum emulation_result kvm_trap_vz_handle_hc(u32 cause, u32 *opc, struct kvm_vcpu *vcpu) { @@ -1407,8 +1419,7 @@ static int kvm_trap_vz_handle_guest_exit(struct kvm_vcpu *vcpu) break; case MIPS_GCTL0_GEXC_GHFC: ++vcpu->stat.vz_ghfc_exits; - er = kvm_trap_vz_no_handler_guest_exit(gexccode, cause, opc, - vcpu); + er = kvm_trap_vz_handle_ghfc(cause, opc, vcpu); break; case MIPS_GCTL0_GEXC_GPA: ++vcpu->stat.vz_gpa_exits; @@ -2459,6 +2470,12 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu) */ kvm_vz_restore_timer(vcpu); + /* Set MC bit if we want to trace guest mode changes */ + if (kvm_trace_guest_mode_change) + set_c0_guestctl0(MIPS_GCTL0_MC); + else + clear_c0_guestctl0(MIPS_GCTL0_MC); + /* Don't bother restoring registers multiple times unless necessary */ if (!all) return 0; -- git-series 0.8.10
next prev parent reply other threads:[~2017-03-14 10:30 UTC|newest] Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-14 10:15 [PATCH v2 0/33] KVM: MIPS: Add VZ support James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 1/33] MIPS: Add defs & probing of UFR James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 2/33] MIPS: Separate MAAR V bit into VL and VH for XPA James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 3/33] MIPS: Probe guest CP0_UserLocal James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 4/33] MIPS: Probe guest MVH James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 5/33] MIPS: Add some missing guest CP0 accessors & defs James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 6/33] MIPS: asm/tlb.h: Add UNIQUE_GUEST_ENTRYHI() macro James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 7/33] KVM: MIPS: Implement HYPCALL emulation James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 8/33] KVM: MIPS/Emulate: De-duplicate MMIO emulation James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 9/33] KVM: MIPS/Emulate: Implement 64-bit " James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 10/33] KVM: MIPS: Update kvm_lose_fpu() for VZ James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 11/33] KVM: MIPS: Extend counters & events for VZ GExcCodes James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 12/33] KVM: MIPS: Add VZ & TE capabilities James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 13/33] KVM: MIPS: Add 64BIT capability James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 14/33] KVM: MIPS: Init timer frequency from callback James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 15/33] KVM: MIPS: Add callback to check extension James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 16/33] KVM: MIPS: Add hardware_{enable,disable} callback James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 17/33] KVM: MIPS: Add guest exit exception callback James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 18/33] KVM: MIPS: Abstract guest CP0 register access for VZ James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 19/33] KVM: MIPS/Entry: Update entry code to support VZ James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 20/33] KVM: MIPS/TLB: Add VZ TLB management James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 21/33] KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 22/33] KVM: MIPS/Emulate: Drop CACHE " James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 23/33] KVM: MIPS: Update exit handler " James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 24/33] KVM: MIPS: Implement VZ support James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 25/33] KVM: MIPS: Add VZ support to build system James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-16 11:40 ` kbuild test robot 2017-03-16 11:40 ` kbuild test robot 2017-03-16 12:50 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 26/33] KVM: MIPS/VZ: Support guest CP0_BadInstr[P] James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 27/33] KVM: MIPS/VZ: Support guest CP0_[X]ContextConfig James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 28/33] KVM: MIPS/VZ: Support guest segmentation control James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 29/33] KVM: MIPS/VZ: Support guest hardware page table walker James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 30/33] KVM: MIPS/VZ: Support guest load-linked bit James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 31/33] KVM: MIPS/VZ: Emulate MAARs when necessary James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` [PATCH v2 32/33] KVM: MIPS/VZ: Support hardware guest timer James Hogan 2017-03-14 10:15 ` James Hogan 2017-03-14 10:15 ` James Hogan [this message] 2017-03-14 10:15 ` [PATCH v2 33/33] KVM: MIPS/VZ: Trace guest mode changes James Hogan 2017-03-15 16:32 ` [PATCH v2 0/33] KVM: MIPS: Add VZ support Ralf Baechle
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