Paolo Bonzini <pbonz...@redhat.com> 于2020年9月20日周日 下午3:56写道： > > On 08/09/20 18:41, Li Qiang wrote: > > Currently the qemu device fuzzer find some DMA to MMIO issue. If the > > device handling MMIO currently trigger a DMA which the address is MMIO, > > this will reenter the device MMIO handler. As some of the device doesn't > > consider this it will sometimes crash the qemu. > > > > This patch tries to solve this by adding a per-device flag 'in_mmio'. > > When the memory core dispatch MMIO it will check/set this flag and when > > it leaves it will clean this flag. > > > > > > Li Qiang (4): > > memory: add memory_region_init_io_with_dev interface > > memory: avoid reenter the device's MMIO handler while processing MMIO > > e1000e: use the new memory_region_init_io_with_dev interface > > hcd-xhci: use the new memory_region_init_io_with_dev interface > > > > hw/net/e1000e.c | 8 ++++---- > > hw/usb/hcd-xhci.c | 25 ++++++++++++++--------- > > include/exec/memory.h | 9 +++++++++ > > include/hw/qdev-core.h | 1 + > > softmmu/memory.c | 46 +++++++++++++++++++++++++++++++++++++++--- > > 5 files changed, 72 insertions(+), 17 deletions(-) > > > > I don't think this is a good solution. These are device bugs and they > need to be fixed.
I agree with this the device should finally handle their cases. But we can do something in a pattern if the device hasn't do that. I have posted a patchset: -->https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg00906.html This is add flags in the Device State. And check/record the flag when doing reentrancy code. Once the device has fixed the reentrancy issue, they can remove this flag. Thanks, Li QIang > > Paolo >
