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fa7f6c2c83
There is a deadlock when emulate_mem is called on the memory region
of PCI extended configuration space. The call trace is something like:
emulate_mem
-> pci_emul_ecfg_handler
-> pci_cfgrw
-> pci_emul_cmdsts_write
-> unregister_bar/register_bar
-> modify_bar_registration
-> unregister_mem/register_mem
mmio_rwlock is hold in emulate_mem when calling unregister_mem/
register_mem which is trying to acquire mmio_rwlock again, and deadlock
happened.
It is possible that bar address is changed just between a on-going
MMIO access which can bring a race condition in theroy. Guest needs to
take care of the serial operation between bar addess update and MMIO
access of that bar.
Tracked-On: #2962
Signed-off-by: Yu Wang <yu1.wang@intel.com>
Signed-off-by: Jian Jun Chen <jian.jun.chen@intel.com>
Signed-off-by: Liu Shuo A <shuo.a.liu@intel.com>
Acked-by: Yin Fengwei <fengwei.yin@intel.com>