Hi Tamas, On 16/09/2016 10:43, Tamas K Lengyel wrote:
The ARM SMC instructions are already configured to trap to Xen by default. In this patch we allow a user-space process in a privileged domain to receive notification of when such event happens through the vm_event subsystem by introducing the PRIVILEGED_CALL type.The intended use-case for this feature is for a monitor application to be able insert tap-points into the domU kernel-code. For this task only unconditional SMC instruction should be used. Signed-off-by: Tamas K Lengyel <tamas.leng...@zentific.com> Acked-by: Wei Liu <wei.l...@citrix.com> Acked-by: Razvan Cojocaru <rcojoc...@bitdefender.com> --- Cc: Ian Jackson <ian.jack...@eu.citrix.com> Cc: Stefano Stabellini <sstabell...@kernel.org> Cc: Julien Grall <julien.gr...@arm.com> v4: Style fixes Note: previous discussion around this patch proposed filtering SMCs with failed condition checks. As that patch is yet-to-be implemented and the 4.8 code-freeze rapidly approaching I would like this patch to get included. In this patch a proper warning is placed in the public header for potential users not to rely on SMCs with failed condition checks being trapped. As the intended use-case for this feature doesn't use conditional SMCs this warning should be sufficient. Hardware that does issue events for SMCs with failed condition checks doesn't pose a problem for a monitor application in any way. The xen-access test tool illustrates how SMCs issued by the guest can be safely handled for all cases.
I will let Stefano decides whether we should include this patch as it in Xen 4.8.
Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
