On Wed, Apr 04, 2018 at 11:29:39PM +0800, Chao Gao wrote: > ... the same page with other registers which are not relevant to MSI-X. Xen > marks pages where PBA resides as read-only. When assigning such devices to > guest, device driver writes MSI-X irrelevant registers on those pages would > lead to an EPT violation and the guest is destroyed because no handler is > registered for those address range. In order to make guest capable to use such > kind of devices, trapping very frequent write accesses is not a good idea for > it would significantly impact the performance. > > This patch provides a workaround with caveat. Specifically, an option is > introduced to specify a list of devices. For those devices, Xen doesn't > control the access right to pages where PBA resides. Hence, guest device > driver is able to write those pages and functions well. Note that adding an > untrusted device to this option may endanger security of the entire system.
This is a clear violation of the MSI-X spec. Out of curiosity, which device is it that places random registers in the same page as the PBA? Thanks, Roger. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
