From: Jim Fehlig Date: Tue, 24 May 2011 13:50:00 +0000 (+0100) Subject: libxc: after saving, unmap correct amount for live_m2p X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~10324 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=18219eb5586da3ecfb06754a1160fe129e26e987;p=xen.git libxc: after saving, unmap correct amount for live_m2p With some help from Olaf, I've finally got to the bottom of an issue I came across while trying to implement save/restore in the libvirt libxenlight driver. After issuing the save operation, the saved domain was not being cleaned up properly and left in this state from xl's perspective xen33:# xl list Name ID Mem VCPUs State Time(s) Domain-0 0 6821 8 r----- 122.5 (null) 2 2 2 --pssd 10.8 Checking the libvirtd /proc/$pid/maps I found this 7f3798984000-7f3798b86000 r--s 00002000 00:03 4026532097 /proc/xen/privcmd So not all all pages belonging to the domain were unmapped from libvirtd. In tools/libxc/xc_domain_save.c we found that P2M_FL_ENTRIES were being mapped but only P2M_FLL_ENTRIES were being unmapped. The attached patch changes the unmapping to use the same P2M_FL_ENTRIES macro. I'm not too familiar with this code though so posting here for review. I suspect this was not noticed before since most (all?) processes doing save terminate after the save and are not long-running like libvirtd. Ian Campbell writes: > Looks like I introduced this in 18558:ccf0205255e1, sorry! > > I guess it is also wrong in the error path out of map_and_save_p2m_table > and so we also need [another hunk]. This change should be backported to relevant earlier trees. -iwj From: Jim Fehlig From: Ian Campbell Signed-off-by: Ian Jackson Cc: Olaf Hering Acked-by: Ian Campbell Acked-by: Ian Jackson Committed-by: Ian Jackson --- diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c index fa270f51f6..4deca18a16 100644 --- a/tools/libxc/xc_domain_save.c +++ b/tools/libxc/xc_domain_save.c @@ -861,7 +861,7 @@ static xen_pfn_t *map_and_save_p2m_table(xc_interface *xch, out: if ( !success && p2m ) - munmap(p2m, P2M_FLL_ENTRIES * PAGE_SIZE); + munmap(p2m, P2M_FL_ENTRIES * PAGE_SIZE); if ( live_p2m_frame_list_list ) munmap(live_p2m_frame_list_list, PAGE_SIZE); @@ -1955,7 +1955,7 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter munmap(live_shinfo, PAGE_SIZE); if ( ctx->live_p2m ) - munmap(ctx->live_p2m, P2M_FLL_ENTRIES * PAGE_SIZE); + munmap(ctx->live_p2m, P2M_FL_ENTRIES * PAGE_SIZE); if ( ctx->live_m2p ) munmap(ctx->live_m2p, M2P_SIZE(ctx->max_mfn));