x86/mm/cpa: Unconditionally avoid WBINDV when we can (ddd07b75) · Commits · 戴 / test

CAT has happened, WBINDV is bad (even before CAT blowing away the entire cache on a multi-core platform wasn't nice), try not to use it ever. Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Reviewed-by:

Dave Hansen <dave.hansen@intel.com> Cc: Bin Yang <bin.yang@intel.com> Cc: Mark Gross <mark.gross@intel.com> Link: https://lkml.kernel.org/r/20180919085947.933674526@infradead.org

arch/x86/mm/pageattr.c

+2 −16

Original line number	Diff line number	Diff line
		@@ -319,26 +319,12 @@ static void cpa_flush_array(unsigned long *start, int numpages, int cache,
		int in_flags, struct page **pages)
		{
		unsigned int i, level;
		#ifdef CONFIG_PREEMPT
		/*
		* Avoid wbinvd() because it causes latencies on all CPUs,
		* regardless of any CPU isolation that may be in effect.
		*
		* This should be extended for CAT enabled systems independent of
		* PREEMPT because wbinvd() does not respect the CAT partitions and
		* this is exposed to unpriviledged users through the graphics
		* subsystem.
		*/
		unsigned long do_wbinvd = 0;
		#else
		unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */
		#endif

		BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);

		on_each_cpu(__cpa_flush_all, (void *) do_wbinvd, 1);
		flush_tlb_all();

		if (!cache \|\| do_wbinvd)
		if (!cache)
		return;

		/*

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