From: Paolo Bonzini <pbonzini@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Frederic Weisbecker <frederic@kernel.org>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Joel Fernandes <joel@joelfernandes.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Brian Gerst <brgerst@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Will Deacon <will@kernel.org>
Subject: Re: [patch V4 part 2 14/18] x86/kvm/vmx: Add hardirq tracing to guest enter/exit
Date: Wed, 6 May 2020 09:55:21 +0200 [thread overview]
Message-ID: <6217b923-fc1b-29c3-cab7-04b7d2d6a0fb@redhat.com> (raw)
In-Reply-To: <20200505134341.471542318@linutronix.de>
On 05/05/20 15:41, Thomas Gleixner wrote:
> Add hardirq tracing to guest enter/exit functions in the same way as it
> is done in the user mode enter/exit code.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
> arch/x86/kvm/vmx/vmx.c | 25 +++++++++++++++++++++++--
> 1 file changed, 23 insertions(+), 2 deletions(-)
>
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6604,9 +6604,19 @@ static void vmx_vcpu_run(struct kvm_vcpu
> x86_spec_ctrl_set_guest(vmx->spec_ctrl, 0);
>
> /*
> - * Tell context tracking that this CPU is about to enter guest mode.
> + * VMENTER enables interrupts (host state), but the kernel state is
> + * interrupts disabled when this is invoked. Also tell RCU about
> + * it. This is the same logic as for exit_to_user_mode().
> + *
> + * 1) Trace interrupts on state
> + * 2) Prepare lockdep with RCU on
> + * 3) Invoke context tracking if enabled to adjust RCU state
> + * 4) Tell lockdep that interrupts are enabled
> */
> + trace_hardirqs_on_prepare();
> + lockdep_hardirqs_on_prepare(CALLER_ADDR0);
> guest_enter_irqoff();
> + lockdep_hardirqs_on(CALLER_ADDR0);
>
> /* L1D Flush includes CPU buffer clear to mitigate MDS */
> if (static_branch_unlikely(&vmx_l1d_should_flush))
> @@ -6623,9 +6633,20 @@ static void vmx_vcpu_run(struct kvm_vcpu
> vcpu->arch.cr2 = read_cr2();
>
> /*
> - * Tell context tracking that this CPU is back.
> + * VMEXIT disables interrupts (host state), but tracing and lockdep
> + * have them in state 'on'. Same as enter_from_user_mode().
> + *
> + * 1) Tell lockdep that interrupts are disabled
> + * 2) Invoke context tracking if enabled to reactivate RCU
> + * 3) Trace interrupts off state
> + *
> + * This needs to be done before the below as native_read_msr()
> + * contains a tracepoint and x86_spec_ctrl_restore_host() calls
> + * into world and some more.
> */
> + lockdep_hardirqs_off(CALLER_ADDR0);
> guest_exit_irqoff();
> + trace_hardirqs_off_prepare();
>
> /*
> * We do not use IBRS in the kernel. If this vCPU has used the
>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
next prev parent reply other threads:[~2020-05-06 7:55 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 13:41 [patch V4 part 2 00/18] x86/entry: Entry/exception code rework, syscall and KVM changes Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 01/18] x86/entry/64: Move non entry code into .text section Thomas Gleixner
2020-05-06 15:51 ` Peter Zijlstra
2020-05-08 1:31 ` Steven Rostedt
2020-05-08 23:53 ` Andy Lutomirski
2020-05-10 13:39 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 02/18] x86/entry/32: " Thomas Gleixner
2020-05-07 13:15 ` Alexandre Chartre
2020-05-07 14:14 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 03/18] x86/entry: Mark enter_from_user_mode() noinstr Thomas Gleixner
2020-05-08 8:21 ` Masami Hiramatsu
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 04/18] x86/entry/common: Protect against instrumentation Thomas Gleixner
2020-05-07 13:39 ` Alexandre Chartre
2020-05-07 14:13 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code Thomas Gleixner
2020-05-07 13:55 ` Alexandre Chartre
2020-05-07 14:10 ` Thomas Gleixner
2020-05-07 15:03 ` Thomas Gleixner
2020-05-07 17:06 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 06/18] x86/entry: Move irq flags tracing to prepare_exit_to_usermode() Thomas Gleixner
2020-05-08 23:57 ` Andy Lutomirski
2020-05-09 10:16 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 07/18] context_tracking: Ensure that the critical path cannot be instrumented Thomas Gleixner
2020-05-08 8:23 ` Masami Hiramatsu
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 08/18] lib/smp_processor_id: Move it into noinstr section Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline tip-bot2 for Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] lib/smp_processor_id: Move it into noinstr section tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 09/18] x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 10/18] x86/entry/64: Check IF in __preempt_enable_notrace() thunk Thomas Gleixner
2020-05-07 14:15 ` Alexandre Chartre
2020-05-09 0:10 ` Andy Lutomirski
2020-05-09 10:25 ` Thomas Gleixner
2020-05-10 18:47 ` Thomas Gleixner
2020-05-11 18:27 ` Thomas Gleixner
2020-05-12 1:48 ` Steven Rostedt
2020-05-12 1:51 ` Steven Rostedt
2020-05-12 8:14 ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 11/18] x86/entry/64: Mark ___preempt_schedule_notrace() thunk noinstr Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 12/18] x86,objtool: Make entry_64_compat.S objtool clean Thomas Gleixner
2020-05-09 0:11 ` Andy Lutomirski
2020-05-09 10:06 ` Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] x86/entry: " tip-bot2 for Peter Zijlstra
2020-05-05 13:41 ` [patch V4 part 2 13/18] x86/kvm: Move context tracking where it belongs Thomas Gleixner
2020-05-06 7:42 ` Paolo Bonzini
2020-05-09 0:14 ` Andy Lutomirski
2020-05-09 10:12 ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 14/18] x86/kvm/vmx: Add hardirq tracing to guest enter/exit Thomas Gleixner
2020-05-06 7:55 ` Paolo Bonzini [this message]
2020-05-05 13:41 ` [patch V4 part 2 15/18] x86/kvm/svm: Handle hardirqs proper on " Thomas Gleixner
2020-05-06 8:15 ` Paolo Bonzini
2020-05-06 8:48 ` Thomas Gleixner
2020-05-06 9:21 ` Paolo Bonzini
2020-05-07 14:44 ` [patch V5 " Thomas Gleixner
2020-05-08 13:45 ` Paolo Bonzini
2020-05-08 14:01 ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 16/18] context_tracking: Make guest_enter/exit() .noinstr ready Thomas Gleixner
2020-05-19 19:58 ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 17/18] x86/kvm/vmx: Move guest enter/exit into .noinstr.text Thomas Gleixner
2020-05-06 8:17 ` Paolo Bonzini
2020-05-05 13:41 ` [patch V4 part 2 18/18] x86/kvm/svm: " Thomas Gleixner
2020-05-06 8:17 ` Paolo Bonzini
2020-05-07 14:47 ` Alexandre Chartre
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