>>> On 19.04.17 at 15:49, <andrew.coop...@citrix.com> wrote: > If a PV kernel is aware of UMIP and turns UMIP on, #GPs from userspace > should be bounced to the kernel, and #GPs from kernel space (as it is > ring-deprivileged) must be emulated and execute successfully. > > If Xen is using UMIP to protect itself, it needs to emulate and fake up > the information to both guest userspace and kernelspace. > > If both Xen and the PV kernel turn on UMIP, Xen needs to bounce > userspace #GPs to the guest kernel, and fake up information for the > guest kernel.
I disagree in one point: If the guest kernel enabled UMIP, it being PV it should take care not to execute any of the covered insns (it has no use for them anyway). I see no reason to emulate anything in that case - emulation is needed only to keep _unaware_ environments working. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
