[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Woes of NMIs and MCEs, and possibly how to fix
>>> On 03.12.12 at 12:24, George Dunlap <dunlapg@xxxxxxxxx> wrote: > On Fri, Nov 30, 2012 at 5:34 PM, Andrew Cooper >> As for 1 possible solution which we cant use: >> >> If it were not for the sysret stupidness[1] of requiring the hypervisor >> to move to the guest stack before executing the `sysret` instruction, we >> could do away with the stack tables for NMIs and MCEs alltogether, and >> the above crazyness would be easy to fix. However, the overhead of >> always using iret to return to ring3 is not likely to be acceptable, >> meaning that we cannot "fix" the problem by discarding interrupt stacks >> and doing everything properly on the main hypervisor stack. >> > > 64-bit Intel processors have SYSEXIT, right? It's worth pointing out the > following alternatives, even if we never actually use them: > > 1. Use SYSEXIT on Intel processors and let the bugs (or some subset of > them) remain on AMD > 2. Use SYSEXIT on Intel processors and IRET on AMD SYSEXIT isn't very suitable because you'd have to corrupt %edx, i.e. it couldn't be used for hypercalls with just 1 or 2 arguments. Plus our GDT layout doesn't match that needed by SYSEXIT, yet some of the selector values are part of the ABI. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |