Messages in this thread | | | Date | Fri, 20 Mar 2015 09:44:02 -0400 | From | Boris Ostrovsky <> | Subject | Re: [Patch V2 2/2] xen: before ballooning hotplugged memory, set frames to invalid |
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On 03/20/2015 08:55 AM, Juergen Gross wrote: > Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set > regions above the end of RAM as 1:1") introduced a regression. > > To be able to add memory pages which were added via memory hotplug to > a pv domain, the pages must be "invalid" instead of "identity" in the > p2m list before they can be added. > > Suggested-by: David Vrabel <david.vrabel@citrix.com> > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > drivers/xen/balloon.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 0b52d92..65fedb8 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -229,6 +229,19 @@ static enum bp_state reserve_additional_memory(long credit) > balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); > nid = memory_add_physaddr_to_nid(hotplug_start_paddr); > > +#ifdef CONFIG_XEN_HAVE_PVMMU > + if (!xen_feature(XENFEAT_auto_translated_physmap)) { > + unsigned long pfn, i; > + > + pfn = PFN_DOWN(hotplug_start_paddr); > + for (i = 0; i < balloon_hotplug; i++) > + if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { > + pr_warn("set_phys_to_machine() failed, no memory added\n"); > + return BP_ECANCELED;
I should have asked last time --- should we restore [0..i-1] mapping back to identity on error here? I wonder whether leaving those frames as invalid (when they are expected to be 'identity') could cause problems in the future.
-boris
> + } > + } > +#endif > + > rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); > > if (rc) {
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