----- 19 cze 2020 o 13:34, Roger Pau Monné roger....@citrix.com napisał(a):
> On Fri, Jun 19, 2020 at 01:38:00AM +0200, Michał Leszczyński wrote: >> Replace on-stack array allocation with heap allocation >> in order to lift the limit of 32 items in mfn/gfn arrays >> when calling acquire_resource. > > I'm afraid this is not correct, you cannot allow unbounded amounts of > items to be processed like this, it's likely that you manage to > trigger the watchdog if the list is long enough, specially when doing > set_foreign_p2m_entry. > > You need to process the items in batches (32 was IMO a good start), and > then add support for hypercall continuations. Take a look at how > XENMEM_populate_physmap just a couple of lines below makes use of > hypercall_create_continuation. > > After processing every batch you need to check if > hypercall_preempt_check returns true and if so use > hypercall_create_continuation in order to encode a continuation. > > Thanks, Roger. Somebody previously suggested that this limit could be lifted this way, so I would like to hear some more opinions on that. Best regards, Michał Leszczyński CERT Polska
