Migration of a "none" machine with no RAM crashes abruptly as
bitmap_new() fails and thus aborts. Instead place zero RAM checks at
appropriate places to skip migration of RAM in this case and complete
migration successfully for devices only.
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
---
Changes in v3:
- handle migration cleanup appropriately (Dave)
Changes in v2:
- try to migrate successfully by skipping RAM (Paolo, Greg)
- drop the idea of erroring out and failing nicely
---
migration/ram.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index ef8fadf..faff5ab 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in
ram_addr_t space */
+ /* No dirty page as there is zero RAM */
+ if (!ram_bytes_total()) {
+ return pages;
+ }
+
pss.block = last_seen_block;
pss.offset = last_offset;
pss.complete_round = false;
@@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void)
bytes_transferred = 0;
reset_ram_globals();
- ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
- migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
- bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
-
- if (migrate_postcopy_ram()) {
- migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
- bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
+ /* Skip setting bitmap if there is no RAM */
+ if (ram_bytes_total()) {
+ ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+ migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
+ bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
+
+ if (migrate_postcopy_ram()) {
+ migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
+ bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
+ }
}
/*
--
2.6.2
* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote: > Migration of a "none" machine with no RAM crashes abruptly as > bitmap_new() fails and thus aborts. Instead place zero RAM checks at > appropriate places to skip migration of RAM in this case and complete > migration successfully for devices only. > > Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > Changes in v3: > - handle migration cleanup appropriately (Dave) > Changes in v2: > - try to migrate successfully by skipping RAM (Paolo, Greg) > - drop the idea of erroring out and failing nicely > --- > migration/ram.c | 22 +++++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index ef8fadf..faff5ab 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage, > ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in > ram_addr_t space */ > > + /* No dirty page as there is zero RAM */ > + if (!ram_bytes_total()) { > + return pages; > + } > + > pss.block = last_seen_block; > pss.offset = last_offset; > pss.complete_round = false; > @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void) > bytes_transferred = 0; > reset_ram_globals(); > > - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > migration_bitmap_rcu = g_new0(struct BitmapRcu, 1); > - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > - > - if (migrate_postcopy_ram()) { > - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + /* Skip setting bitmap if there is no RAM */ > + if (ram_bytes_total()) { > + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > + > + if (migrate_postcopy_ram()) { > + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + } > } > > /* > -- > 2.6.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 02/08/2017 11:28 AM, Ashijeet Acharya wrote: > Migration of a "none" machine with no RAM crashes abruptly as > bitmap_new() fails and thus aborts. Instead place zero RAM checks at > appropriate places to skip migration of RAM in this case and complete > migration successfully for devices only. > > Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > Changes in v3: > - handle migration cleanup appropriately (Dave) > Changes in v2: > - try to migrate successfully by skipping RAM (Paolo, Greg) > - drop the idea of erroring out and failing nicely > --- > migration/ram.c | 22 +++++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index ef8fadf..faff5ab 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage, > ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in > ram_addr_t space */ > > + /* No dirty page as there is zero RAM */ > + if (!ram_bytes_total()) { > + return pages; > + } > + > pss.block = last_seen_block; > pss.offset = last_offset; > pss.complete_round = false; > @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void) > bytes_transferred = 0; > reset_ram_globals(); > > - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > migration_bitmap_rcu = g_new0(struct BitmapRcu, 1); > - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > - > - if (migrate_postcopy_ram()) { > - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + /* Skip setting bitmap if there is no RAM */ > + if (ram_bytes_total()) { > + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > + > + if (migrate_postcopy_ram()) { > + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + } > } > > /* >
* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote: > Migration of a "none" machine with no RAM crashes abruptly as > bitmap_new() fails and thus aborts. Instead place zero RAM checks at > appropriate places to skip migration of RAM in this case and complete > migration successfully for devices only. > > Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> Queued. > --- > Changes in v3: > - handle migration cleanup appropriately (Dave) > Changes in v2: > - try to migrate successfully by skipping RAM (Paolo, Greg) > - drop the idea of erroring out and failing nicely > --- > migration/ram.c | 22 +++++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index ef8fadf..faff5ab 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage, > ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in > ram_addr_t space */ > > + /* No dirty page as there is zero RAM */ > + if (!ram_bytes_total()) { > + return pages; > + } > + > pss.block = last_seen_block; > pss.offset = last_offset; > pss.complete_round = false; > @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void) > bytes_transferred = 0; > reset_ram_globals(); > > - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > migration_bitmap_rcu = g_new0(struct BitmapRcu, 1); > - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > - > - if (migrate_postcopy_ram()) { > - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + /* Skip setting bitmap if there is no RAM */ > + if (ram_bytes_total()) { > + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS; > + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages); > + > + if (migrate_postcopy_ram()) { > + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages); > + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages); > + } > } > > /* > -- > 2.6.2 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
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