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[31.46.240.70]) by smtp.gmail.com with ESMTPSA id h13-20020a05600c314d00b0041ac4aafd3dsm25365112wmo.12.2024.04.29.22.55.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Apr 2024 22:55:37 -0700 (PDT) Sender: Ingo Molnar Date: Tue, 30 Apr 2024 07:55:35 +0200 From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: linux-tip-commits@vger.kernel.org, Adrian Huang , Thomas Gleixner , "Borislav Petkov (AMD)" , stable@vger.kernel.org, x86@kernel.org Subject: Re: [tip: x86/urgent] x86/apic: Don't access the APIC when disabling X2APIC Message-ID: References: <875xw5t6r7.ffs@tglx> <171439414186.10875.17224463643261311678.tip-bot2@tip-bot2> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <171439414186.10875.17224463643261311678.tip-bot2@tip-bot2> * tip-bot2 for Thomas Gleixner wrote: > - apic_set_fixmap(); > + /* > + * Don't reread the APIC ID as it was already done from > + * check_x2apic() and the apic driver still is a x2APIC variant, > + * which fails to do the read after x2APIC was disabled. > + */ > + apic_set_fixmap(false); JFYI, I amended the commit with the fixlet below, to avoid the inevitable followup trivial patch: diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b229648b7a18..803dcfb0e346 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1795,7 +1795,7 @@ static __init void x2apic_disable(void) __x2apic_disable(); /* * Don't reread the APIC ID as it was already done from - * check_x2apic() and the apic driver still is a x2APIC variant, + * check_x2apic() and the APIC driver still is a x2APIC variant, * which fails to do the read after x2APIC was disabled. */ apic_set_fixmap(false); Thanks, Ingo