On 20/11/2017 19:08, Peter Maydell wrote: > To do a write to memory that is marked as notdirty, we need > to invalidate any TBs we have cached for that memory, and > update the cpu physical memory dirty flags for VGA and migration. > The slowpath code in notdirty_mem_write() does all this correctly, > but the new atomic handling code in atomic_mmu_lookup() doesn't > do anything at all, it just clears the dirty bit in the TLB. > > The effect of this bug is that if the first write to a notdirty > page for which we have cached TBs is by a guest atomic access, > we fail to invalidate the TBs and subsequently will execute > incorrect code. This can be seen by trying to run 'javac' on AArch64. > > The first patch here refactors notdirty_mem_write() to pull out > the "correctly handle dirty bit updates" parts of the code into > two new functions memory_notdirty_write_prepare() and > memory_notdirty_write_complete(). The second patch then uses > those functions to fix the atomic helpers.
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com> Thanks! Paolo > Changes v1->v2: > * add the 'bool active;' flag to NotDirtyInfo in patch 1 > * change the comment on NotDirtyInfo in patch 1 to document > the active flag (and to fix incorrect references to function > names that I forgot to update when I decided on the names for > the prepare/complete functions) > * in patch 2, don't call prepare unless the TLB was notdirty > * in patch 2, use the active flag to track whether we need to > call complete or not > > thanks > -- PMM > > Peter Maydell (2): > exec.c: Factor out before/after actions for notdirty memory writes > accel/tcg: Handle atomic accesses to notdirty memory correctly > > accel/tcg/atomic_template.h | 12 ++++++++ > include/exec/memory-internal.h | 62 ++++++++++++++++++++++++++++++++++++++++ > accel/tcg/cputlb.c | 38 +++++++++++++++--------- > accel/tcg/user-exec.c | 1 + > exec.c | 65 > ++++++++++++++++++++++++++++-------------- > 5 files changed, 144 insertions(+), 34 deletions(-) >
