From: Ashok Raj <ashok.raj@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, <x86@kernel.org>,
Ashok Raj <ashok.raj@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Tony Luck" <tony.luck@intel.com>,
Arjan van de Veen <arjan@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Eric Biederman <ebiederm@xmission.com>,
Ashok Raj <ashok.raj@intel.com>
Subject: Re: [patch 6/6] x86/smp: Put CPUs into INIT on shutdown if possible
Date: Sat, 3 Jun 2023 13:57:14 -0700 [thread overview]
Message-ID: <ZHupKtSqj1LC911k@a4bf019067fa.jf.intel.com> (raw)
In-Reply-To: <20230603200459.947733085@linutronix.de>
On Sat, Jun 03, 2023 at 10:07:04PM +0200, Thomas Gleixner wrote:
> Parking CPUs in a HLT loop is not completely safe vs. kexec() as HLT can
> resume execution due to NMI, SMI and MCE, which has the same issue as the
> MWAIT loop.
>
> Kicking the secondary CPUs into INIT makes this safe against NMI and SMI.
>
> A broadcast MCE will take the machine down, but a broadcast MCE which makes
> HLT resume and execute overwritten text, pagetables or data will end up in
> a disaster too.
>
> So chose the lesser of two evils and kick the secondary CPUs into INIT
> unless the system has installed special wakeup mechanisms which are not
> using INIT.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For the whole series.
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
next prev parent reply other threads:[~2023-06-03 20:59 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-03 20:06 [patch 0/6] Cure kexec() vs. mwait_play_dead() troubles Thomas Gleixner
2023-06-03 20:06 ` [patch 1/6] x86/smp: Remove pointless wmb() from native_stop_other_cpus() Thomas Gleixner
2023-06-03 20:06 ` [patch 2/6] x86/smp: Acquire stopping_cpu unconditionally Thomas Gleixner
2023-06-03 20:07 ` [patch 3/6] x86/smp: Use dedicated cache-line for mwait_play_dead() Thomas Gleixner
2023-06-03 20:07 ` [patch 4/6] x86/smp: Cure kexec() vs. mwait_play_dead() breakage Thomas Gleixner
2023-06-03 20:54 ` Ashok Raj
2023-06-04 3:19 ` Ashok Raj
2023-06-05 7:41 ` Thomas Gleixner
2023-06-03 20:07 ` [patch 5/6] x86/smp: Split sending INIT IPI out into a helper function Thomas Gleixner
2023-06-04 4:02 ` Mika Penttilä
2023-06-04 10:24 ` Ashok Raj
2023-06-05 7:54 ` Thomas Gleixner
2023-06-05 8:23 ` [patch v2 " Thomas Gleixner
2023-06-03 20:07 ` [patch 6/6] x86/smp: Put CPUs into INIT on shutdown if possible Thomas Gleixner
2023-06-03 20:57 ` Ashok Raj [this message]
2023-06-05 17:41 ` [patch 0/6] Cure kexec() vs. mwait_play_dead() troubles Sean Christopherson
2023-06-05 22:41 ` Thomas Gleixner
2023-06-05 23:08 ` Sean Christopherson
2023-06-06 7:20 ` Thomas Gleixner
2023-06-07 16:21 ` Ashok Raj
2023-06-07 17:33 ` Sean Christopherson
2023-06-07 22:19 ` Ashok Raj
2023-06-08 3:46 ` Sean Christopherson
2023-06-08 4:03 ` Ashok Raj
2023-06-16 15:07 ` Ashok Raj
2023-06-16 19:00 ` Sean Christopherson
2023-06-16 19:03 ` Ashok Raj
2023-06-16 19:08 ` Sean Christopherson
2023-06-09 8:40 ` Paolo Bonzini
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