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Chao Gao
c4b1ef0f89
To remove a device from a domain, a qmp command is sent to qemu. But it is handled by qemu asychronously. Even the qmp command is claimed to be done, the actual handling in qemu side may happen later. This behavior brings two questions: 1. Attaching a device back to a domain right after detaching the device from that domain would fail with error: libxl: error: libxl_qmp.c:341:qmp_handle_error_response: Domain 1:received an error message from QMP server: Duplicate ID 'pci-pt-60_00.0' for device 2. Accesses to PCI configuration space in Qemu may overlap with later device reset issued by 'xl' or by pciback. In order to avoid mentioned questions, wait for the completion of device removal by querying all pci devices using qmp command and ensuring the target device isn't listed. Only retry 5 times to avoid 'xl' potentially being blocked by qemu. Signed-off-by: Chao Gao <chao.gao@intel.com> Message-Id: <1562133373-19208-1-git-send-email-chao.gao@intel.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>