From: Steven Rostedt <rostedt@goodmis.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@ozlabs.org>,
Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Subject: Re: [PATCH v5 06/10] powerpc64/ftrace: Disable ftrace during kvm entry/exit
Date: Thu, 19 Apr 2018 11:22:16 -0400 [thread overview]
Message-ID: <20180419112216.173f8fd6@gandalf.local.home> (raw)
In-Reply-To: <62b77045b205b008946b793fe31effb155b335be.1524121038.git.naveen.n.rao@linux.vnet.ibm.com>
On Thu, 19 Apr 2018 12:34:05 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> 2. If we are a secondary thread in Power8, then we would be in nap due
> to SMT being disabled. We are woken up by an IPI to enter the guest. In
> this scenario, we enter the guest through kvm_start_guest(). We disable
> ftrace at this point. In this scenario, ftrace would only get re-enabled
> on the secondary thread when SMT is re-enabled (via start_secondary()).
>
trace_hardirqs_off();
> diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> index bd63fa8a08b5..2c3cbe0067b2 100644
> --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> @@ -342,6 +342,9 @@ kvm_start_guest:
>
> ld r2,PACATOC(r13)
>
You may want to add a comment here about where ftrace gets re-enabled.
-- Steve
> + li r0,0
> + stb r0,PACA_FTRACE_ENABLED(r13)
> +
> li r0,KVM_HWTHREAD_IN_KVM
> stb r0,HSTATE_HWTHREAD_STATE(r13)
>
next prev parent reply other threads:[~2018-04-19 20:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-19 7:03 [PATCH v5 00/10] powerpc64/ftrace: Add support for ftrace_modify_call() and a few other fixes Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 01/10] powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths Naveen N. Rao
2018-05-08 14:52 ` [v5, " Michael Ellerman
2018-04-19 7:04 ` [PATCH v5 02/10] powerpc64/ftrace: Rearrange #ifdef sections in ftrace.h Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 03/10] powerpc64/ftrace: Add helpers to hard disable ftrace Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 04/10] powerpc64/ftrace: Delay enabling ftrace on secondary cpus Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 05/10] powerpc64/ftrace: Disable ftrace during hotplug Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 06/10] powerpc64/ftrace: Disable ftrace during kvm entry/exit Naveen N. Rao
2018-04-19 15:22 ` Steven Rostedt [this message]
2018-04-20 6:31 ` Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 07/10] powerpc64/kexec: Hard disable ftrace before switching to the new kernel Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 08/10] powerpc64/module: Tighten detection of mcount call sites with -mprofile-kernel Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 09/10] powerpc64/ftrace: Use the generic version of ftrace_replace_code() Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 10/10] powerpc64/ftrace: Implement support for ftrace_regs_caller() Naveen N. Rao
2018-04-19 15:28 ` [PATCH v5 00/10] powerpc64/ftrace: Add support for ftrace_modify_call() and a few other fixes Steven Rostedt
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