target/arm:Set lg_page_size to 0 if either S1 or S2 asks for it
In get_phys_addr_twostage() we set the lg_page_size of the result to the maximum of the stage 1 and stage 2 page sizes. This works for the case where we do want to create a TLB entry, because we know the common TLB code only creates entries of the TARGET_PAGE_SIZE and asking for a size larger than that only means that invalidations invalidate the whole larger area. However, if lg_page_size is smaller than TARGET_PAGE_SIZE this effectively means "don't create a TLB entry"; in this case if either S1 or S2 said "this covers less than a page and can't go in a TLB" then the final result also should be marked that way. Set the resulting page size to 0 if either stage asked for a less-than-a-page entry, and expand the comment to explain what's going on. This has no effect for VMSA because currently the VMSA lookup always returns results that cover at least TARGET_PAGE_SIZE; however when we add v8R support it will reuse this code path, and for v8R the S1 and S2 results can be smaller than TARGET_PAGE_SIZE. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20221212142708.610090-1-peter.maydell@linaro.org
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@ -2655,10 +2655,20 @@ static bool get_phys_addr_twostage(CPUARMState *env, S1Translate *ptw,
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/*
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/*
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* Use the maximum of the S1 & S2 page size, so that invalidation
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* If either S1 or S2 returned a result smaller than TARGET_PAGE_SIZE,
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* of pages > TARGET_PAGE_SIZE works correctly.
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* this means "don't put this in the TLB"; in this case, return a
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* result with lg_page_size == 0 to achieve that. Otherwise,
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* use the maximum of the S1 & S2 page size, so that invalidation
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* of pages > TARGET_PAGE_SIZE works correctly. (This works even though
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* we know the combined result permissions etc only cover the minimum
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* of the S1 and S2 page size, because we know that the common TLB code
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* never actually creates TLB entries bigger than TARGET_PAGE_SIZE,
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* and passing a larger page size value only affects invalidations.)
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*/
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*/
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if (result->f.lg_page_size < s1_lgpgsz) {
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if (result->f.lg_page_size < TARGET_PAGE_BITS ||
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s1_lgpgsz < TARGET_PAGE_BITS) {
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result->f.lg_page_size = 0;
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} else if (result->f.lg_page_size < s1_lgpgsz) {
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result->f.lg_page_size = s1_lgpgsz;
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result->f.lg_page_size = s1_lgpgsz;
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}
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}
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