x86/mm/cpa: Fix cpa_flush_array() TLB invalidation

In commit:

  a7295fd5 ("x86/mm/cpa: Use flush_tlb_kernel_range()")

I misread the CAP array code and incorrectly used
tlb_flush_kernel_range(), resulting in missing TLB flushes and
consequent failures.

Instead do a full invalidate in this case -- for now.
Reported-by: StDenis, Tom <Tom.StDenis@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@intel.com
Fixes: a7295fd5 ("x86/mm/cpa: Use flush_tlb_kernel_range()")
Link: http://lkml.kernel.org/r/20181203171043.089868285@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/mm/pageattr.c

@@ -285,20 +285,16 @@ static void cpa_flush_all(unsigned long cache)
 	on_each_cpu(__cpa_flush_all, (void *) cache, 1);
 }
 
-static bool __cpa_flush_range(unsigned long start, int numpages, int cache)
+static bool __inv_flush_all(int cache)
 {
 	BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
 
-	WARN_ON(PAGE_ALIGN(start) != start);
-
 	if (cache && !static_cpu_has(X86_FEATURE_CLFLUSH)) {
 		cpa_flush_all(cache);
 		return true;
 	}
 
-	flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
-
-	return !cache;
+	return false;
 }
 
 static void cpa_flush_range(unsigned long start, int numpages, int cache)
@@ -306,7 +302,14 @@ static void cpa_flush_range(unsigned long start, int numpages, int cache)
 	unsigned int i, level;
 	unsigned long addr;
 
-	if (__cpa_flush_range(start, numpages, cache))
+	WARN_ON(PAGE_ALIGN(start) != start);
+
+	if (__inv_flush_all(cache))
+		return;
+
+	flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
+
+	if (!cache)
 		return;
 
 	/*
@@ -332,7 +335,12 @@ static void cpa_flush_array(unsigned long baddr, unsigned long *start,
 {
 	unsigned int i, level;
 
-	if (__cpa_flush_range(baddr, numpages, cache))
+	if (__inv_flush_all(cache))
+		return;
+
+	flush_tlb_all();
+
+	if (!cache)
 		return;
 
 	/*