On Tue, May 06, 2025 at 11:20:41AM +0100, Julien Grall wrote: > Hi Roger, > > On 06/05/2025 09:31, Roger Pau Monne wrote: > > Such flag is added to the domain create hypercall, and a matching option is > > added to xl and libxl to set the flag: `cache_control`. When the flag is > > set, the domain is allowed the usage of cache control operations. > > Can you clarify whether you are talking about using the hypercall to flush > the cache or the instructions?
On x86 at least: both hypercall and instructions if possible, since Xen traps cache flush instructions. Maybe that's different on ARM. As said on a previous reply I've assumed that cache_flush_permitted() was also relevant on ARM, but maybe it's not and domains are unconditionally allowed execution of cache control instructions and hypercalls. Thanks, Roger.
