Re: [Xen-devel] [PATCH] Hypercalls from HVM guests

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 22 Apr 2006, at 16:16, Steve Ofsthun wrote:

> > (1) is most important right now -- we should only permit the 
> > hypercalls we need, and audit any others before they are added to the 
> > list.
> OK, is a bitmap filter of the inbound requests sufficient?  For this 
> patch, I'll
> just filter every hypercall except HYPERVISOR_xen_version() and return 
> ENOSYS?
That would be okay, but also:
 1. VMMCALL_MAGIC needs to go, and be replaced by a first-class 
hypercall (HYPERVISOR_hvm_op maybe). Either by having an hvm-specific 
hypercall table, or by adding to the main jump table and have the 
hvm_op function itself bail on non-hvm guests.
 2. guest_handle_okay() should always return TRUE for an hvm guest
 3. get rid of the __user modifiers in your new functions in 
guest_access.h. We don't use those in Xen (except in a few files taken 
fairly directly from Linux).
 -- Keir


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