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From: Luke Dashjr <luke@dashjr.org>
To: linux-kernel@vger.kernel.org, trivial@kernel.org, x86@kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Subject: [PATCH] arch/x86: Encourage rather than discourage x2apic support
Date: Wed, 31 Mar 2021 05:16:41 +0000	[thread overview]
Message-ID: <202103310516.42497.luke@dashjr.org> (raw)

Multi-core SMP doesn't work on modern Intel CPUs (at least Comet Lake) without
x2apic. Unsure users should say Y.
    
Signed-off-by: Luke Dashjr <luke-jr+git@utopios.org>
---
 arch/x86/Kconfig | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2792879d398ee..ddb42707bd069 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -446,9 +446,10 @@ config X86_X2APIC
          This enables x2apic support on CPUs that have this feature.
 
          This allows 32-bit apic IDs (so it can support very large systems),
-         and accesses the local apic via MSRs not via mmio.
+         and accesses the local apic via MSRs not via mmio. It is also needed
+         to use multiple cores on modern Intel CPUs.
 
-         If you don't know what to do here, say N.
+         If you don't know what to do here, say Y.
 
 config X86_MPPARSE
        bool "Enable MPS table" if ACPI
--
2.6.23

             reply	other threads:[~2021-03-31  5:31 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-31  5:16 Luke Dashjr [this message]
2021-04-10  9:30 ` [PATCH] arch/x86: Encourage rather than discourage x2apic support Thomas Gleixner

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