| Message ID | 20191015075444.10955-2-peterx@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | apic: Fix migration breakage of >255 vcpus | expand |
Peter Xu <peterx@redhat.com> wrote: > It was "int" and used as 32bits fields (see save_section_header()). > It's unsafe already because sizeof(int) could be 2 on i386, i386 is 32bits, so int is 32bits O:-) I really hope that we would never, ever, need a 64bits instance id. It would mean that we have more than 2.000.000.000 objects of the same type, no? I am pretty sure than in 16bits platforms we have other problems than insntance_id (namely that we don't have enough memory). >I think. > So at least uint32_t would suite more. While it also uses "-1" as a > placeholder of "we want to generate the instance ID automatically". > Hence a more proper value should be int64_t. > > This will start to be useful after next patch in which we can start to > convert a real uint32_t value as instance ID. Later, Juan.
Peter Xu <peterx@redhat.com> wrote: > It was "int" and used as 32bits fields (see save_section_header()). > It's unsafe already because sizeof(int) could be 2 on i386, I think. > So at least uint32_t would suite more. While it also uses "-1" as a > placeholder of "we want to generate the instance ID automatically". > Hence a more proper value should be int64_t. > > This will start to be useful after next patch in which we can start to > convert a real uint32_t value as instance ID. > > Signed-off-by: Peter Xu <peterx@redhat.com> Hi Being more helpful, I think that it is better to just: * change instance_id to be an uint32_t (notice that for all architectures that we support, it is actually int32_t). * export calculate_new_instance_id() and adjust callers that use -1. or * export a new function that just use the calculate_new_instance_id() A fast search shows: 10 callers of vmstate_register() with -1 1 caller of vmstate_register_with_alias_id with -1 (but it is the one that sets all qdev devices). 1 caller of vmstate_register_with_alias_id in apic, where it can be -1. 1 caller of register_savevm_live() with -1 (spapr) And call it a day? What do you think, Juan. > --- > include/migration/register.h | 2 +- > include/migration/vmstate.h | 4 ++-- > migration/savevm.c | 10 +++++----- > stubs/vmstate.c | 2 +- > 4 files changed, 9 insertions(+), 9 deletions(-) > > diff --git a/include/migration/register.h b/include/migration/register.h > index a13359a08d..54f42c7413 100644 > --- a/include/migration/register.h > +++ b/include/migration/register.h > @@ -69,7 +69,7 @@ typedef struct SaveVMHandlers { > } SaveVMHandlers; > > int register_savevm_live(const char *idstr, > - int instance_id, > + int64_t instance_id, > int version_id, > const SaveVMHandlers *ops, > void *opaque); > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > index 1fbfd099dd..6a7498463c 100644 > --- a/include/migration/vmstate.h > +++ b/include/migration/vmstate.h > @@ -1114,14 +1114,14 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, > bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque); > > /* Returns: 0 on success, -1 on failure */ > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > const VMStateDescription *vmsd, > void *base, int alias_id, > int required_for_version, > Error **errp); > > /* Returns: 0 on success, -1 on failure */ > -static inline int vmstate_register(DeviceState *dev, int instance_id, > +static inline int vmstate_register(DeviceState *dev, int64_t instance_id, > const VMStateDescription *vmsd, > void *opaque) > { > diff --git a/migration/savevm.c b/migration/savevm.c > index bb9462a54d..dc9281c897 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -233,7 +233,7 @@ typedef struct CompatEntry { > typedef struct SaveStateEntry { > QTAILQ_ENTRY(SaveStateEntry) entry; > char idstr[256]; > - int instance_id; > + int64_t instance_id; > int alias_id; > int version_id; > /* version id read from the stream */ > @@ -668,7 +668,7 @@ void dump_vmstate_json_to_file(FILE *out_file) > static int calculate_new_instance_id(const char *idstr) > { > SaveStateEntry *se; > - int instance_id = 0; > + int64_t instance_id = 0; > > QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > if (strcmp(idstr, se->idstr) == 0 > @@ -730,7 +730,7 @@ static void savevm_state_handler_insert(SaveStateEntry *nse) > Meanwhile pass -1 as instance_id if you do not already have a clearly > distinguishing id for all instances of your device class. */ > int register_savevm_live(const char *idstr, > - int instance_id, > + int64_t instance_id, > int version_id, > const SaveVMHandlers *ops, > void *opaque) > @@ -784,7 +784,7 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque) > } > } > > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > const VMStateDescription *vmsd, > void *opaque, int alias_id, > int required_for_version, > @@ -1566,7 +1566,7 @@ int qemu_save_device_state(QEMUFile *f) > return qemu_file_get_error(f); > } > > -static SaveStateEntry *find_se(const char *idstr, int instance_id) > +static SaveStateEntry *find_se(const char *idstr, int64_t instance_id) > { > SaveStateEntry *se; > > diff --git a/stubs/vmstate.c b/stubs/vmstate.c > index e1e89b87f0..699003f3b0 100644 > --- a/stubs/vmstate.c > +++ b/stubs/vmstate.c > @@ -4,7 +4,7 @@ > const VMStateDescription vmstate_dummy = {}; > > int vmstate_register_with_alias_id(DeviceState *dev, > - int instance_id, > + int64_t instance_id, > const VMStateDescription *vmsd, > void *base, int alias_id, > int required_for_version,
* Juan Quintela (quintela@redhat.com) wrote: > Peter Xu <peterx@redhat.com> wrote: > > It was "int" and used as 32bits fields (see save_section_header()). > > It's unsafe already because sizeof(int) could be 2 on i386, I think. > > So at least uint32_t would suite more. While it also uses "-1" as a > > placeholder of "we want to generate the instance ID automatically". > > Hence a more proper value should be int64_t. > > > > This will start to be useful after next patch in which we can start to > > convert a real uint32_t value as instance ID. > > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > Hi > > Being more helpful, I think that it is better to just: > > * change instance_id to be an uint32_t (notice that for all architectures > that we support, it is actually int32_t). > > * export calculate_new_instance_id() and adjust callers that use -1. > > or > > * export a new function that just use the calculate_new_instance_id() Do you mean that we end up with two functions, one that does it automatically, and one that takes an ID? Dave > A fast search shows: > > 10 callers of vmstate_register() with -1 > 1 caller of vmstate_register_with_alias_id with -1 (but it is the one > that sets all qdev devices). > 1 caller of vmstate_register_with_alias_id in apic, where it can be -1. > 1 caller of register_savevm_live() with -1 (spapr) > > And call it a day? > > What do you think, Juan. > > > --- > > include/migration/register.h | 2 +- > > include/migration/vmstate.h | 4 ++-- > > migration/savevm.c | 10 +++++----- > > stubs/vmstate.c | 2 +- > > 4 files changed, 9 insertions(+), 9 deletions(-) > > > > diff --git a/include/migration/register.h b/include/migration/register.h > > index a13359a08d..54f42c7413 100644 > > --- a/include/migration/register.h > > +++ b/include/migration/register.h > > @@ -69,7 +69,7 @@ typedef struct SaveVMHandlers { > > } SaveVMHandlers; > > > > int register_savevm_live(const char *idstr, > > - int instance_id, > > + int64_t instance_id, > > int version_id, > > const SaveVMHandlers *ops, > > void *opaque); > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > > index 1fbfd099dd..6a7498463c 100644 > > --- a/include/migration/vmstate.h > > +++ b/include/migration/vmstate.h > > @@ -1114,14 +1114,14 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, > > bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque); > > > > /* Returns: 0 on success, -1 on failure */ > > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *base, int alias_id, > > int required_for_version, > > Error **errp); > > > > /* Returns: 0 on success, -1 on failure */ > > -static inline int vmstate_register(DeviceState *dev, int instance_id, > > +static inline int vmstate_register(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *opaque) > > { > > diff --git a/migration/savevm.c b/migration/savevm.c > > index bb9462a54d..dc9281c897 100644 > > --- a/migration/savevm.c > > +++ b/migration/savevm.c > > @@ -233,7 +233,7 @@ typedef struct CompatEntry { > > typedef struct SaveStateEntry { > > QTAILQ_ENTRY(SaveStateEntry) entry; > > char idstr[256]; > > - int instance_id; > > + int64_t instance_id; > > int alias_id; > > int version_id; > > /* version id read from the stream */ > > @@ -668,7 +668,7 @@ void dump_vmstate_json_to_file(FILE *out_file) > > static int calculate_new_instance_id(const char *idstr) > > { > > SaveStateEntry *se; > > - int instance_id = 0; > > + int64_t instance_id = 0; > > > > QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > > if (strcmp(idstr, se->idstr) == 0 > > @@ -730,7 +730,7 @@ static void savevm_state_handler_insert(SaveStateEntry *nse) > > Meanwhile pass -1 as instance_id if you do not already have a clearly > > distinguishing id for all instances of your device class. */ > > int register_savevm_live(const char *idstr, > > - int instance_id, > > + int64_t instance_id, > > int version_id, > > const SaveVMHandlers *ops, > > void *opaque) > > @@ -784,7 +784,7 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque) > > } > > } > > > > -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, > > +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, > > const VMStateDescription *vmsd, > > void *opaque, int alias_id, > > int required_for_version, > > @@ -1566,7 +1566,7 @@ int qemu_save_device_state(QEMUFile *f) > > return qemu_file_get_error(f); > > } > > > > -static SaveStateEntry *find_se(const char *idstr, int instance_id) > > +static SaveStateEntry *find_se(const char *idstr, int64_t instance_id) > > { > > SaveStateEntry *se; > > > > diff --git a/stubs/vmstate.c b/stubs/vmstate.c > > index e1e89b87f0..699003f3b0 100644 > > --- a/stubs/vmstate.c > > +++ b/stubs/vmstate.c > > @@ -4,7 +4,7 @@ > > const VMStateDescription vmstate_dummy = {}; > > > > int vmstate_register_with_alias_id(DeviceState *dev, > > - int instance_id, > > + int64_t instance_id, > > const VMStateDescription *vmsd, > > void *base, int alias_id, > > int required_for_version, -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Tue, Oct 15, 2019 at 10:45:53AM +0200, Juan Quintela wrote: > Peter Xu <peterx@redhat.com> wrote: > > It was "int" and used as 32bits fields (see save_section_header()). > > It's unsafe already because sizeof(int) could be 2 on i386, I think. > > So at least uint32_t would suite more. While it also uses "-1" as a > > placeholder of "we want to generate the instance ID automatically". > > Hence a more proper value should be int64_t. > > > > This will start to be useful after next patch in which we can start to > > convert a real uint32_t value as instance ID. > > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > Hi > > Being more helpful, I think that it is better to just: > > * change instance_id to be an uint32_t (notice that for all architectures > that we support, it is actually int32_t). > > * export calculate_new_instance_id() and adjust callers that use -1. > > or > > * export a new function that just use the calculate_new_instance_id() > > A fast search shows: > > 10 callers of vmstate_register() with -1 > 1 caller of vmstate_register_with_alias_id with -1 (but it is the one > that sets all qdev devices). > 1 caller of vmstate_register_with_alias_id in apic, where it can be -1. > 1 caller of register_savevm_live() with -1 (spapr) > > And call it a day? > > What do you think, Juan. Sure, I can switch instance_id to uint32_t and add a new flag to both functions (register_savevm_live, vmstate_register_with_alias_id) Regards,
On Tue, Oct 15, 2019 at 10:34:57AM +0200, Juan Quintela wrote: > Peter Xu <peterx@redhat.com> wrote: > > It was "int" and used as 32bits fields (see save_section_header()). > > It's unsafe already because sizeof(int) could be 2 on i386, > > i386 is 32bits, so int is 32bits O:-) Right it should be 16 bits systems. And yes I don't think we need to consider that! :)
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > * Juan Quintela (quintela@redhat.com) wrote: >> Peter Xu <peterx@redhat.com> wrote: >> > It was "int" and used as 32bits fields (see save_section_header()). >> > It's unsafe already because sizeof(int) could be 2 on i386, I think. >> > So at least uint32_t would suite more. While it also uses "-1" as a >> > placeholder of "we want to generate the instance ID automatically". >> > Hence a more proper value should be int64_t. >> > >> > This will start to be useful after next patch in which we can start to >> > convert a real uint32_t value as instance ID. >> > >> > Signed-off-by: Peter Xu <peterx@redhat.com> >> >> Hi >> >> Being more helpful, I think that it is better to just: >> >> * change instance_id to be an uint32_t (notice that for all architectures >> that we support, it is actually int32_t). >> >> * export calculate_new_instance_id() and adjust callers that use -1. >> >> or >> >> * export a new function that just use the calculate_new_instance_id() > > Do you mean that we end up with two functions, one that does it > automatically, and one that takes an ID? That is one option. The other is that we export calculate_new_instance_id(), and we use that instead of -1. Later, Juan.
diff --git a/include/migration/register.h b/include/migration/register.h index a13359a08d..54f42c7413 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -69,7 +69,7 @@ typedef struct SaveVMHandlers { } SaveVMHandlers; int register_savevm_live(const char *idstr, - int instance_id, + int64_t instance_id, int version_id, const SaveVMHandlers *ops, void *opaque); diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index 1fbfd099dd..6a7498463c 100644 --- a/include/migration/vmstate.h +++ b/include/migration/vmstate.h @@ -1114,14 +1114,14 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque); /* Returns: 0 on success, -1 on failure */ -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, const VMStateDescription *vmsd, void *base, int alias_id, int required_for_version, Error **errp); /* Returns: 0 on success, -1 on failure */ -static inline int vmstate_register(DeviceState *dev, int instance_id, +static inline int vmstate_register(DeviceState *dev, int64_t instance_id, const VMStateDescription *vmsd, void *opaque) { diff --git a/migration/savevm.c b/migration/savevm.c index bb9462a54d..dc9281c897 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -233,7 +233,7 @@ typedef struct CompatEntry { typedef struct SaveStateEntry { QTAILQ_ENTRY(SaveStateEntry) entry; char idstr[256]; - int instance_id; + int64_t instance_id; int alias_id; int version_id; /* version id read from the stream */ @@ -668,7 +668,7 @@ void dump_vmstate_json_to_file(FILE *out_file) static int calculate_new_instance_id(const char *idstr) { SaveStateEntry *se; - int instance_id = 0; + int64_t instance_id = 0; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (strcmp(idstr, se->idstr) == 0 @@ -730,7 +730,7 @@ static void savevm_state_handler_insert(SaveStateEntry *nse) Meanwhile pass -1 as instance_id if you do not already have a clearly distinguishing id for all instances of your device class. */ int register_savevm_live(const char *idstr, - int instance_id, + int64_t instance_id, int version_id, const SaveVMHandlers *ops, void *opaque) @@ -784,7 +784,7 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque) } } -int vmstate_register_with_alias_id(DeviceState *dev, int instance_id, +int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id, const VMStateDescription *vmsd, void *opaque, int alias_id, int required_for_version, @@ -1566,7 +1566,7 @@ int qemu_save_device_state(QEMUFile *f) return qemu_file_get_error(f); } -static SaveStateEntry *find_se(const char *idstr, int instance_id) +static SaveStateEntry *find_se(const char *idstr, int64_t instance_id) { SaveStateEntry *se; diff --git a/stubs/vmstate.c b/stubs/vmstate.c index e1e89b87f0..699003f3b0 100644 --- a/stubs/vmstate.c +++ b/stubs/vmstate.c @@ -4,7 +4,7 @@ const VMStateDescription vmstate_dummy = {}; int vmstate_register_with_alias_id(DeviceState *dev, - int instance_id, + int64_t instance_id, const VMStateDescription *vmsd, void *base, int alias_id, int required_for_version,
It was "int" and used as 32bits fields (see save_section_header()). It's unsafe already because sizeof(int) could be 2 on i386, I think. So at least uint32_t would suite more. While it also uses "-1" as a placeholder of "we want to generate the instance ID automatically". Hence a more proper value should be int64_t. This will start to be useful after next patch in which we can start to convert a real uint32_t value as instance ID. Signed-off-by: Peter Xu <peterx@redhat.com> --- include/migration/register.h | 2 +- include/migration/vmstate.h | 4 ++-- migration/savevm.c | 10 +++++----- stubs/vmstate.c | 2 +- 4 files changed, 9 insertions(+), 9 deletions(-)