| Message ID | 20201017210102.26036-2-eafanasova@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | softmmu/memory: fix memory_region_ioeventfd_equal() | expand |
On Sat, Oct 17, 2020 at 02:01:02PM -0700, Elena Afanasova wrote: > Eventfd can be registered with a zero length when fast_mmio is true. > Handle this case properly when dispatching through QEMU. > > Signed-off-by: Elena Afanasova <eafanasova@gmail.com> > --- > softmmu/memory.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/softmmu/memory.c b/softmmu/memory.c > index 403ff3abc9..3ca2154a64 100644 > --- a/softmmu/memory.c > +++ b/softmmu/memory.c > @@ -203,10 +203,17 @@ static bool memory_region_ioeventfd_before(MemoryRegionIoeventfd *a, > } > > static bool memory_region_ioeventfd_equal(MemoryRegionIoeventfd *a, > - MemoryRegionIoeventfd *b) > -{ > - return !memory_region_ioeventfd_before(a, b) > - && !memory_region_ioeventfd_before(b, a); > + MemoryRegionIoeventfd *mrb) Why rename b -> mrb? > +{ > + if (int128_eq(a->addr.start, mrb->addr.start) && > + (!int128_nz(mrb->addr.size) || > + int128_eq(a->addr.size, mrb->addr.size)) && > + (a->match_data == mrb->match_data) && > + ((mrb->match_data && (a->data == mrb->data)) || !mrb->match_data) && > + (a->e == mrb->e)) > + return true; The kernel behaves differently in that a and b are symmetric: static bool ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) { struct _ioeventfd *_p; list_for_each_entry(_p, &kvm->ioeventfds, list) if (_p->bus_idx == p->bus_idx && _p->addr == p->addr && (!_p->length || !p->length || (_p->length == p->length && (_p->wildcard || p->wildcard || _p->datamatch == p->datamatch)))) return true; return false; } For example, if a->addr.size == 0 then the ioeventfd matches whereas this patch only does it for b. Please match the kernel behavior. A different approach is setting ioeventfd.addr.size to zero when mr->ioeventfds[i].addr.size is zero in the memory_region_dispatch_write_eventfds() loop. That way memory_region_ioeventfd_equal() doesn't need to be modified.
diff --git a/softmmu/memory.c b/softmmu/memory.c index 403ff3abc9..3ca2154a64 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -203,10 +203,17 @@ static bool memory_region_ioeventfd_before(MemoryRegionIoeventfd *a, } static bool memory_region_ioeventfd_equal(MemoryRegionIoeventfd *a, - MemoryRegionIoeventfd *b) -{ - return !memory_region_ioeventfd_before(a, b) - && !memory_region_ioeventfd_before(b, a); + MemoryRegionIoeventfd *mrb) +{ + if (int128_eq(a->addr.start, mrb->addr.start) && + (!int128_nz(mrb->addr.size) || + int128_eq(a->addr.size, mrb->addr.size)) && + (a->match_data == mrb->match_data) && + ((mrb->match_data && (a->data == mrb->data)) || !mrb->match_data) && + (a->e == mrb->e)) + return true; + + return false; } /* Range of memory in the global map. Addresses are absolute. */
Eventfd can be registered with a zero length when fast_mmio is true. Handle this case properly when dispatching through QEMU. Signed-off-by: Elena Afanasova <eafanasova@gmail.com> --- softmmu/memory.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)