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arch-arm: Fix page size handling when merging stage 1 and 2

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The current code to merge translation entries from stage 1 and stage 2
doesn't handle cases where the page sizes at the different stages
differ. This change fixes both the case when the hypervisor has a
larger page size and when it has a smaller page size.

Change-Id: Icdf289005bf1e4de4d91d54643924a38d9d77796
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10505
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
This commit is contained in:
Andreas Sandberg
2018-05-16 15:27:32 +01:00
parent 1fc48cc454
commit 7f82aa3d60
1 changed files with 5 additions and 4 deletions
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9
src/arch/arm/stage2_lookup.cc
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@@ -88,23 +88,24 @@ Stage2LookUp::mergeTe(RequestPtr req, BaseTLB::Mode mode)
// Now we have the table entries for both stages of translation
// merge them and insert the result into the stage 1 TLB. See
// CombineS1S2Desc() in pseudocode
stage1Te.N = stage2Te->N;
stage1Te.nonCacheable |= stage2Te->nonCacheable;
stage1Te.xn |= stage2Te->xn;
if (stage1Te.size > stage2Te->size) {
// Size mismatch also implies vpn mismatch (this is shifted by
// sizebits!).
stage1Te.vpn = s1Req->getVaddr() / (stage2Te->size+1);
stage1Te.vpn = s1Req->getVaddr() >> stage2Te->N;
stage1Te.pfn = stage2Te->pfn;
stage1Te.size = stage2Te->size;
stage1Te.N = stage2Te->N;
} else if (stage1Te.size < stage2Te->size) {
// Guest 4K could well be section-backed by host hugepage! In this
// case a 4K entry is added but pfn needs to be adjusted. New PFN =
// offset into section PFN given by stage2 IPA treated as a stage1
// page size.
stage1Te.pfn = (stage2Te->pfn * ((stage2Te->size+1) / (stage1Te.size+1))) +
(stage2Te->vpn / (stage1Te.size+1));
const Addr pa = (stage2Te->pfn << stage2Te->N);
const Addr ipa = (stage1Te.pfn << stage1Te.N);
stage1Te.pfn = (pa | (ipa & mask(stage2Te->N))) >> stage1Te.N;
// Size remains smaller of the two.
} else {
// Matching sizes