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Piccoli" , Piotr Gorski , David Woodhouse , Usama Arif , Juergen Gross , Boris Ostrovsky , xen-devel@lists.xenproject.org, Russell King , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Guo Ren , linux-csky@vger.kernel.org, Thomas Bogendoerfer , linux-mips@vger.kernel.org, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Mark Rutland , Sabin Rapan Subject: Re: [patch 00/37] cpu/hotplug, x86: Reworked parallel CPU bringup Message-ID: <20230417103050.GF83892@hirez.programming.kicks-ass.net> References: <20230414225551.858160935@linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230414225551.858160935@linutronix.de> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Apr 15, 2023 at 01:44:13AM +0200, Thomas Gleixner wrote: > Background > ---------- > > The reason why people are interested in parallel bringup is to shorten > the (kexec) reboot time of cloud servers to reduce the downtime of the > VM tenants. There are obviously other interesting use cases for this > like VM startup time, embedded devices... ... > There are two issue there: > > a) The death by MCE broadcast problem > > Quite some (contemporary) x86 CPU generations are affected by > this: > > - MCE can be broadcasted to all CPUs and not only issued locally > to the CPU which triggered it. > > - Any CPU which has CR4.MCE == 0, even if it sits in a wait > for INIT/SIPI state, will cause an immediate shutdown of the > machine if a broadcasted MCE is delivered. When doing kexec, CR4.MCE should already have been set to 1 by the prior kernel, no? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel