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Subject[PATCH 3/8] x86/mm/cpa: Unconditionally avoid WBINDV when we can
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>
---
arch/x86/mm/pageattr.c | 18 ++----------------
1 file changed, 2 insertions(+), 16 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -319,26 +319,12 @@ static void cpa_flush_array(unsigned lon
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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