Hi Marc,

On 2021/6/2 18:22, Marc Zyngier wrote:

On Thu, 15 Apr 2021 12:50:30 +0100,
Yanan Wang [off-list ref] wrote:

quoted

We want to move I-cache maintenance for the guest to the stage-2
page table code for performance improvement. Before it can work,
we should first make function invalidate_icache_range available
to non-VHE EL2 to avoid compiling or program running error, as
pgtable.c is now linked into the non-VHE EL2 code for pKVM mode.

In this patch, we only introduce symbol of invalidate_icache_range
with no real functionality in nvhe/cache.S, because there haven't
been situations found currently where I-cache maintenance is also
needed in non-VHE EL2 for pKVM mode.

Signed-off-by: Yanan Wang <redacted>
---
  arch/arm64/kvm/hyp/nvhe/cache.S | 11 +++++++++++
  1 file changed, 11 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/cache.S b/arch/arm64/kvm/hyp/nvhe/cache.S
index 36cef6915428..a125ec9aeed2 100644
--- a/arch/arm64/kvm/hyp/nvhe/cache.S
+++ b/arch/arm64/kvm/hyp/nvhe/cache.S

@@ -11,3 +11,14 @@ SYM_FUNC_START_PI(__flush_dcache_area)
  	dcache_by_line_op civac, sy, x0, x1, x2, x3
  	ret
  SYM_FUNC_END_PI(__flush_dcache_area)
+
+/*
+ *	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
+ */
+SYM_FUNC_START(invalidate_icache_range)
+SYM_FUNC_END(invalidate_icache_range)

This is a good indication that something is really wrong.

If you were to provide cache management callbacks as part of the
mm_ops themselves (or a similar abstraction), you wouldn't have to do
these things.

Yes, we definitely don't need this work if we do that.

Thanks,
Yanan

	M.

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