Hi Tamas,
On 08/01/2020 17:14, Tamas K Lengyel wrote:
+static int mem_sharing_fork(struct domain *d, struct domain *cd)
+{
+ int rc;
+
+ if ( !d->controller_pause_count &&
+ (rc = domain_pause_by_systemcontroller(d)) )
AFAIU, the parent domain will be paused if it wasn't paused before and
this will not be unpaused by the same hypercall. Right?
If so, this brings two questions:
- What would happen if the toolstack decide to unpause the domain?
- How does the caller knows whether this was paused by the
hypercall or not?
I would also suggest to document the behavior of the hypercall as this
is not entirely obvious that the domain will be paused here.
+ return rc;
+
+ cd->max_pages = d->max_pages;
+ cd->max_vcpus = d->max_vcpus;
+
+ /* this is preemptible so it's the first to get done */
+ if ( (rc = fork_hap_allocation(d, cd)) )
+ return rc;
+
+ if ( (rc = bring_up_vcpus(cd, d->cpupool)) )
+ return rc;
+
+ if ( (rc = hvm_copy_context_and_params(d, cd)) )
+ return rc;
+
+ fork_tsc(d, cd);
+
+ cd->parent = d;
How do you ensure that the parent domain will not get destroyed before
the forked domain? Do you have a refcount somewhere?
+
+ return 0;
+}
+
Cheers,
--
Julien Grall
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