[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V8] xen/vm_event: Clean up control-register-write vm_events and add XCR0 event
On Tue, 2015-06-02 at 16:43 +0100, Andrew Cooper wrote: > On 02/06/15 16:39, Ian Campbell wrote: > > On Fri, 2015-05-29 at 16:45 +0300, Razvan Cojocaru wrote: > >> As suggested by Andrew Cooper, this patch attempts to remove > >> some redundancy and allow for an easier time when adding vm_events > >> for new control registers in the future, by having a single > >> VM_EVENT_REASON_WRITE_CTRLREG vm_event type, meant to serve CR0, > >> CR3, CR4 and (newly introduced) XCR0. The actual control register > >> will be deduced by the new .index field in vm_event_write_ctrlreg > >> (renamed from vm_event_mov_to_cr). The patch has also modified > >> the xen-access.c test - it is now able to log CR3 events. > >> > >> Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx> > >> Acked-by: Jan Beulich <jbeulich@xxxxxxxx> > > Seems ok from the tools and arm side, so long as the xen-access.c test > > is likely to build on ARM despite the new x86-isms (it looks like it to > > me) and the following Q: > > > >> +/* Supported values for the vm_event_write_ctrlreg index. */ > >> +#define VM_EVENT_X86_CR0 0 > >> +#define VM_EVENT_X86_CR3 1 > >> +#define VM_EVENT_X86_CR4 2 > >> +#define VM_EVENT_X86_XCR0 3 > > Is the intention for different architectures to use non-overlapping > > number spaces? (i.e. ARM would start from 0x10000 or something)? > > > > If not then the usages in xen-access.c are a little more problematic. I > > can just about tolerate a tool on arm which asks "monitor x86 cr3" and > > then never sees anything, but to get events for whatever ARM reg happens > > to share the index instead would be wrong I think. > > When I suggested this, I expected each arch to maintain its own index > space and for these spaces to all start at 0, as there is very little > which is truly common at this level. That's fine too, but implies that tests/xen-access.c therefore needs some additional #ifdeffery. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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