On 07/03/2019 13:32, Peter Zijlstra wrote: > On Thu, Mar 07, 2019 at 01:22:52PM +0100, Juergen Gross wrote: >> On 07/03/2019 12:45, Peter Zijlstra wrote: >>> drivers/xen/privcmd.o: warning: objtool: privcmd_ioctl()+0x1414: call to >>> hypercall_page() with UACCESS enabled >>> >>> Xen needs to do HV calls with AC=1 for hysterical raisins. Make the >>> warning go away. >> >> No, this is a hypercall with parameters passed through from user land >> (Xen tools). So setting AC=1 is not related to hysterical reasons, but >> to indicate that unprivileged buffers are okay here. So please change >> the commit message to something like: >> >> Some Xen hypercalls allow parameter buffers in user land, so they need >> to set AC=1. Avoid the warning for those cases. > > *yuck* that's gross... > > And I understood from Andrew yesterday (but perhaps I misunderstood) > that the whole privcmd thing was a bit of a hack.
That was an unwise design decision in the past, yes. Changing it will require a lot of effort. > But sure, I'll change the message. Thanks. :-) Juergen
