On Tue, Dec 12, 2023 at 10:57:17AM +0000, Alejandro Vallejo wrote: > The procedure used to customize the domain CPU policy is broken when > toolstack tries to set leaves (with subleaves) that the hypervisor didn't > need to serialise (i.e: because they where empty subleaves). > > During typical domain creation xg does the following: > > 1. Probe Xen for max #leaves that a policy may have > 2. Allocate memory for that many leaves > 3. Tell the hypervisor to dump the policy in the allocated buffer > 4. Deserialise it > 5. Modify it > 6. Reserialise it > 7. Send it back to Xen > > The problem is that (3) overrides nr_leaves, which then makes (6) fail in > the case where (5) has added subleaves that Xen understands but didn't need > to serialize on (3). > > The fix uses an opaque CPU policy object so we can (a) avoid probing Xen > for sizes, and (b) trivially have knowledge of the actual size of the > buffer. > > While at it, fix xc_cpu_policy_destroy() to preserve errno accross free() > > Signed-off-by: Alejandro Vallejo <[email protected]>
Reviewed-by: Anthony PERARD <[email protected]> Thanks, -- Anthony PERARD
