arm64: KVM: Add invalidate_icache_range helper

We currently tightly couple dcache clean with icache invalidation,
but KVM could do without the initial flush to PoU, as we've
already flushed things to PoC.

Let's introduce invalidate_icache_range which is limited to
invalidating the icache from the linear mapping (and thus
has none of the userspace fault handling complexity), and
wire it in KVM instead of flush_icache_range.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 22 insertions, 10 deletions

diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 7f1dbe962cf5..bedd23da83f4 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -60,16 +60,7 @@ user_alt 9f, "dc cvau, x4",  "dc civac, x4",  ARM64_WORKAROUND_CLEAN_CACHE
 	b.lo	1b
 	dsb	ish
 
-	icache_line_size x2, x3
-	sub	x3, x2, #1
-	bic	x4, x0, x3
-1:
-USER(9f, ic	ivau, x4	)		// invalidate I line PoU
-	add	x4, x4, x2
-	cmp	x4, x1
-	b.lo	1b
-	dsb	ish
-	isb
+	invalidate_icache_by_line x0, x1, x2, x3, 9f
 	mov	x0, #0
 1:
 	uaccess_ttbr0_disable x1
@@ -81,6 +72,27 @@ ENDPROC(flush_icache_range)
 ENDPROC(__flush_cache_user_range)
 
 /*
+ *	invalidate_icache_range(start,end)
+ *
+ *	Ensure that the I cache is invalid within specified region.
+ *
+ *	- start   - virtual start address of region
+ *	- end     - virtual end address of region
+ */
+ENTRY(invalidate_icache_range)
+	uaccess_ttbr0_enable x2, x3
+
+	invalidate_icache_by_line x0, x1, x2, x3, 2f
+	mov	x0, xzr
+1:
+	uaccess_ttbr0_disable x1
+	ret
+2:
+	mov	x0, #-EFAULT
+	b	1b
+ENDPROC(invalidate_icache_range)
+
+/*
  *	__flush_dcache_area(kaddr, size)
  *
  *	Ensure that any D-cache lines for the interval [kaddr, kaddr+size)