| Message ID | 1479156950-2517-3-git-send-email-quintela@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Juan Quintela (quintela@redhat.com) wrote: > Right now, if we receive a compressed page or a xbzrle page while this > features are disabled, Bad Things (TM) can happen. Just add a test for > them. This confuses me; I didn't think until recently we could guarantee anything about having the capabilities set on the destination side. Until -incoming defer the destination didn't have a way of setting capabilities in a known state before starting the reception. Dave > Signed-off-by: Juan Quintela <quintela@redhat.com> > --- > migration/ram.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/migration/ram.c b/migration/ram.c > index fb9252d..4bb707c 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -2464,7 +2464,7 @@ static int ram_load_postcopy(QEMUFile *f) > > static int ram_load(QEMUFile *f, void *opaque, int version_id) > { > - int flags = 0, ret = 0; > + int flags = 0, ret = 0, invalid_flags; > static uint64_t seq_iter; > int len = 0; > /* > @@ -2479,6 +2479,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > ret = -EINVAL; > } > > + invalid_flags = 0; > + > + if (!migrate_use_xbzrle()) { > + invalid_flags |= RAM_SAVE_FLAG_XBZRLE; > + } > + > + if (!migrate_use_compression()) { > + invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE; > + } > /* This RCU critical section can be very long running. > * When RCU reclaims in the code start to become numerous, > * it will be necessary to reduce the granularity of this > @@ -2499,6 +2508,18 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > flags = addr & ~TARGET_PAGE_MASK; > addr &= TARGET_PAGE_MASK; > > + if (flags & invalid_flags) { > + if (flags & invalid_flags & RAM_SAVE_FLAG_XBZRLE) { > + error_report("Received an unexpected XBRLE page"); > + } > + if (flags & invalid_flags & RAM_SAVE_FLAG_COMPRESS_PAGE) { > + error_report("Received an unexpected compressed page"); > + } > + > + ret = -EINVAL; > + break; > + } > + > if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE | > RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) { > RAMBlock *block = ram_block_from_stream(f, flags); > -- > 2.7.4 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > * Juan Quintela (quintela@redhat.com) wrote: >> Right now, if we receive a compressed page or a xbzrle page while this >> features are disabled, Bad Things (TM) can happen. Just add a test for >> them. > > This confuses me; I didn't think until recently we could > guarantee anything about having the capabilities set on the destination > side. Until -incoming defer the destination didn't have a way of setting > capabilities in a known state before starting the reception. Ouch. So, here we are after further investigation. - xbzrle: we don't need anything special on the reception side, we just decode inplace. So we are good. If we don't use xbzrle, we don't waste any resources either. - compression: We create the decompression threads always, with all its associated configuration. Why do I wanted to do this? For multifd, I don't really want to create multiple fd's except if configured, because I wait for the fd's to be "accepted" before continue, so I need a way to know if it is configured or no. So I need something like this. I started doing this for compression because when I was debugging I had too many threads waiting on qemu_cond_wait(), and I only wanted to look at the multifd ones. I had not througth that we didn't need to set capabilities on destination. Suggestions? Later, Juan. > > Dave > >> Signed-off-by: Juan Quintela <quintela@redhat.com> >> --- >> migration/ram.c | 23 ++++++++++++++++++++++- >> 1 file changed, 22 insertions(+), 1 deletion(-) >> >> diff --git a/migration/ram.c b/migration/ram.c >> index fb9252d..4bb707c 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -2464,7 +2464,7 @@ static int ram_load_postcopy(QEMUFile *f) >> >> static int ram_load(QEMUFile *f, void *opaque, int version_id) >> { >> - int flags = 0, ret = 0; >> + int flags = 0, ret = 0, invalid_flags; >> static uint64_t seq_iter; >> int len = 0; >> /* >> @@ -2479,6 +2479,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) >> ret = -EINVAL; >> } >> >> + invalid_flags = 0; >> + >> + if (!migrate_use_xbzrle()) { >> + invalid_flags |= RAM_SAVE_FLAG_XBZRLE; >> + } >> + >> + if (!migrate_use_compression()) { >> + invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE; >> + } >> /* This RCU critical section can be very long running. >> * When RCU reclaims in the code start to become numerous, >> * it will be necessary to reduce the granularity of this >> @@ -2499,6 +2508,18 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) >> flags = addr & ~TARGET_PAGE_MASK; >> addr &= TARGET_PAGE_MASK; >> >> + if (flags & invalid_flags) { >> + if (flags & invalid_flags & RAM_SAVE_FLAG_XBZRLE) { >> + error_report("Received an unexpected XBRLE page"); >> + } >> + if (flags & invalid_flags & RAM_SAVE_FLAG_COMPRESS_PAGE) { >> + error_report("Received an unexpected compressed page"); >> + } >> + >> + ret = -EINVAL; >> + break; >> + } >> + >> if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE | >> RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) { >> RAMBlock *block = ram_block_from_stream(f, flags); >> -- >> 2.7.4 >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
* Juan Quintela (quintela@redhat.com) wrote: > "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > > * Juan Quintela (quintela@redhat.com) wrote: > >> Right now, if we receive a compressed page or a xbzrle page while this > >> features are disabled, Bad Things (TM) can happen. Just add a test for > >> them. > > > > This confuses me; I didn't think until recently we could > > guarantee anything about having the capabilities set on the destination > > side. Until -incoming defer the destination didn't have a way of setting > > capabilities in a known state before starting the reception. > > Ouch. > > So, here we are after further investigation. > > - xbzrle: we don't need anything special on the reception side, we just > decode inplace. So we are good. If we don't use xbzrle, we > don't waste any resources either. > - compression: We create the decompression threads always, with all its > associated configuration. > > > Why do I wanted to do this? For multifd, I don't really want to create > multiple fd's except if configured, because I wait for the fd's to be > "accepted" before continue, so I need a way to know if it is configured > or no. So I need something like this. > > I started doing this for compression because when I was debugging I had > too many threads waiting on qemu_cond_wait(), and I only wanted to look > at the multifd ones. > > I had not througth that we didn't need to set capabilities on > destination. > > Suggestions? It's fine for new features to require it; newer libvirt already does it for postcopy and does: -incoming defer sets the capabilities and parameters migrate_incoming URI However, enforcing it for old features sounds something we can't do. Dave > Later, Juan. > > > > > Dave > > > >> Signed-off-by: Juan Quintela <quintela@redhat.com> > >> --- > >> migration/ram.c | 23 ++++++++++++++++++++++- > >> 1 file changed, 22 insertions(+), 1 deletion(-) > >> > >> diff --git a/migration/ram.c b/migration/ram.c > >> index fb9252d..4bb707c 100644 > >> --- a/migration/ram.c > >> +++ b/migration/ram.c > >> @@ -2464,7 +2464,7 @@ static int ram_load_postcopy(QEMUFile *f) > >> > >> static int ram_load(QEMUFile *f, void *opaque, int version_id) > >> { > >> - int flags = 0, ret = 0; > >> + int flags = 0, ret = 0, invalid_flags; > >> static uint64_t seq_iter; > >> int len = 0; > >> /* > >> @@ -2479,6 +2479,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > >> ret = -EINVAL; > >> } > >> > >> + invalid_flags = 0; > >> + > >> + if (!migrate_use_xbzrle()) { > >> + invalid_flags |= RAM_SAVE_FLAG_XBZRLE; > >> + } > >> + > >> + if (!migrate_use_compression()) { > >> + invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE; > >> + } > >> /* This RCU critical section can be very long running. > >> * When RCU reclaims in the code start to become numerous, > >> * it will be necessary to reduce the granularity of this > >> @@ -2499,6 +2508,18 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > >> flags = addr & ~TARGET_PAGE_MASK; > >> addr &= TARGET_PAGE_MASK; > >> > >> + if (flags & invalid_flags) { > >> + if (flags & invalid_flags & RAM_SAVE_FLAG_XBZRLE) { > >> + error_report("Received an unexpected XBRLE page"); > >> + } > >> + if (flags & invalid_flags & RAM_SAVE_FLAG_COMPRESS_PAGE) { > >> + error_report("Received an unexpected compressed page"); > >> + } > >> + > >> + ret = -EINVAL; > >> + break; > >> + } > >> + > >> if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE | > >> RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) { > >> RAMBlock *block = ram_block_from_stream(f, flags); > >> -- > >> 2.7.4 > >> > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/migration/ram.c b/migration/ram.c index fb9252d..4bb707c 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2464,7 +2464,7 @@ static int ram_load_postcopy(QEMUFile *f) static int ram_load(QEMUFile *f, void *opaque, int version_id) { - int flags = 0, ret = 0; + int flags = 0, ret = 0, invalid_flags; static uint64_t seq_iter; int len = 0; /* @@ -2479,6 +2479,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) ret = -EINVAL; } + invalid_flags = 0; + + if (!migrate_use_xbzrle()) { + invalid_flags |= RAM_SAVE_FLAG_XBZRLE; + } + + if (!migrate_use_compression()) { + invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE; + } /* This RCU critical section can be very long running. * When RCU reclaims in the code start to become numerous, * it will be necessary to reduce the granularity of this @@ -2499,6 +2508,18 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) flags = addr & ~TARGET_PAGE_MASK; addr &= TARGET_PAGE_MASK; + if (flags & invalid_flags) { + if (flags & invalid_flags & RAM_SAVE_FLAG_XBZRLE) { + error_report("Received an unexpected XBRLE page"); + } + if (flags & invalid_flags & RAM_SAVE_FLAG_COMPRESS_PAGE) { + error_report("Received an unexpected compressed page"); + } + + ret = -EINVAL; + break; + } + if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE | RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) { RAMBlock *block = ram_block_from_stream(f, flags);
Right now, if we receive a compressed page or a xbzrle page while this features are disabled, Bad Things (TM) can happen. Just add a test for them. Signed-off-by: Juan Quintela <quintela@redhat.com> --- migration/ram.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)