From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Len Brown <lenb@kernel.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-pm@vger.kernel.org, Robin Jarry <rjarry@redhat.com>,
Joe Mario <jmario@redhat.com>
Subject: Re: [PATCH v3 1/3] x86/idle: Disable IBRS when cpu is offline
Date: Wed, 21 Jun 2023 22:40:53 -0700 [thread overview]
Message-ID: <20230622054053.uy577qezu5a65buc@treble> (raw)
In-Reply-To: <20230622003603.1188364-2-longman@redhat.com>
On Wed, Jun 21, 2023 at 08:36:01PM -0400, Waiman Long wrote:
> +/*
> + * naitve_play_dead() is essentially a __noreturn function, but it can't
> + * be marked as such as the compiler may complain about it.
> + */
FWIW, we could in theory do so by marking the smp_ops.play_dead function
pointer as __noreturn, but it would be tricky to teach objtool how to
understand that.
> void native_play_dead(void)
> {
> + if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS)) {
> + this_cpu_write(x86_spec_ctrl_current, 0);
> + native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
> + }
Can update_spec_ctrl() be used instead?
--
Josh
next prev parent reply other threads:[~2023-06-22 5:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-22 0:36 [PATCH v3 0/3] x86/speculation: Disable IBRS when idle Waiman Long
2023-06-22 0:36 ` [PATCH v3 1/3] x86/idle: Disable IBRS when cpu is offline Waiman Long
2023-06-22 2:05 ` Randy Dunlap
2023-06-22 2:13 ` Waiman Long
2023-06-22 5:40 ` Josh Poimboeuf [this message]
2023-06-22 12:27 ` Waiman Long
2023-06-22 0:36 ` [PATCH v3 2/3] intel_idle: Sync up the SPEC_CTRL MSR value to x86_spec_ctrl_current Waiman Long
2023-06-22 5:46 ` Josh Poimboeuf
2023-06-22 9:38 ` Peter Zijlstra
2023-06-22 12:43 ` Waiman Long
2023-06-22 13:08 ` Peter Zijlstra
2023-06-22 9:40 ` Peter Zijlstra
2023-06-22 12:34 ` Waiman Long
2023-06-22 12:31 ` Waiman Long
2023-06-22 0:36 ` [PATCH v3 3/3] intel_idle: Add ibrs_off module parameter to force disable IBRS Waiman Long
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