target-ppc: booke206 tlb: fix tlbwe instruction

[Qemu-devel] [PATCH 0/1] target-ppc: booke206 tlb: fix tlbwe instruction

Luc MICHEL posted 1 patch 7 years, 12 months ago

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git fetch https://github.com/patchew-project/qemu tags/patchew/20171102103559.7382-1-luc.michel@git.antfield.fr

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target/ppc/mmu_helper.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

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[Qemu-devel] [PATCH 0/1] target-ppc: booke206 tlb: fix tlbwe instruction

Posted by Luc MICHEL 7 years, 12 months ago

Hi,

I was experiencing random segmentation faults of userland applications
in a guest e500 powerpc Linux. After investigating, I found that this
bug appeared with commit 9fb044911444fdd09f5f072ad0ca269d7f8b841d. This
commit introduces more MMU indices to avoid unnecessary TLB flushes when
the CPU changes mode.

It triggers a new bug however, that I finally traced down into the tlbwe
instructions simulation. When replacing a valid TLB entry with a new
one, the previous page was not flushed from QEMU TLB.

This fixes my random crashes in guest Linux. Note that I think there is
a similar issue in booke206_invalidate_ea_tlb but in my case, Linux
never triggers this code so I was not able to test.

Luc MICHEL (1):
  target-ppc: Fix booke206 tlbwe TLB instruction

 target/ppc/mmu_helper.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

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2.14.3