Messages in this thread | | | Date | Thu, 22 May 2008 10:49:34 +0200 | From | Mikael Pettersson <> | Subject | Re: [RFC] x86: xsave/xrstor support, ucontext_t extensions |
| |
Roland McGrath writes: > > The biggest potential problem with this that I see is that relying on > > CPUID can mess with certain virtualization solutions. Another option to > > accomplish the same thing would be to have a system call (preferrably a > > prctl, since it is at least in theory personality-dependent) to query > > what information is included in the fpstate data - since it will always > > be the same for any particular kernel. > > It's easy and cheap to add an indicator to the vDSO for this.
For our user-space virtualisation code a plain system call, like prctl(), would be strongly preferable. Right now I can't say whether a vDSO solution would work at all for us, but a system call solution would be no problem at all.
/Mikael
| |