Messages in this thread Patch in this message | | | Date | Wed, 12 Sep 2018 12:22:44 -0700 | From | tip-bot for Juergen Gross <> | Subject | [tip:x86/urgent] x86/xen: Disable CPU0 hotplug for Xen PV |
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Commit-ID: 999696752db1099aba595aac4f8d881f8c7cf4e6 Gitweb: https://git.kernel.org/tip/999696752db1099aba595aac4f8d881f8c7cf4e6 Author: Juergen Gross <jgross@suse.com> AuthorDate: Wed, 12 Sep 2018 19:41:22 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 12 Sep 2018 21:15:02 +0200
x86/xen: Disable CPU0 hotplug for Xen PV
Xen PV guests don't allow CPU0 hotplug, so disable it.
Signed-off-by: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: boris.ostrovsky@oracle.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20180912174122.24282-1-jgross@suse.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c index 12cbe2b88c0f..738bf42b0218 100644 --- a/arch/x86/kernel/topology.c +++ b/arch/x86/kernel/topology.c @@ -111,8 +111,10 @@ int arch_register_cpu(int num) /* * Currently CPU0 is only hotpluggable on Intel platforms. Other * vendors can add hotplug support later. + * Xen PV guests don't support CPU0 hotplug at all. */ - if (c->x86_vendor != X86_VENDOR_INTEL) + if (c->x86_vendor != X86_VENDOR_INTEL || + boot_cpu_has(X86_FEATURE_XENPV)) cpu0_hotpluggable = 0; /*
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