On 24 August 2018 at 19:10, Max Filippov <jcmvb...@gmail.com> wrote: > Hi Peter, > > On Fri, Aug 24, 2018 at 10:56 AM, Peter Maydell > <peter.mayd...@linaro.org> wrote: >> On 20 August 2018 at 03:31, Max Filippov <jcmvb...@gmail.com> wrote: >>> Signed-off-by: Max Filippov <jcmvb...@gmail.com> >>> --- >>> target/xtensa/cpu.c | 2 +- >>> target/xtensa/cpu.h | 7 ++++--- >>> target/xtensa/op_helper.c | 12 +++++++----- >>> 3 files changed, 12 insertions(+), 9 deletions(-) >> >> Hi -- thanks for doing this conversion. This change means that >> you'll no longer get guest exceptions for bus errors that happen >> during get_pte()'s page table entry fetch. Don't you need at >> least a TODO comment there indicating that there's missing >> behaviour? > > Thanks for taking a look and letting me know, I've missed that entirely.
Basically the new hook only handles failures for code paths that go via the MMU; anything where the target code does a direct physical address lookup has to handle the failure itself. I think for xtensa that's just the page table reads. (This is why it's a bit of a pain to convert a target, but the end result makes much more sense, because almost always the target code doing physical address accesses doesn't want to handle bus errors by randomly longjumping out.) thanks -- PMM
