Rename vmstate_info_nullptr from "uint64_t" to "nullptr". This vmstate
actually reads and writes just a byte, so the proper name would be
uint8. However, since this is a marker for a NULL pointer, it's
convenient to have a more explicit name that can be identified by the
consumers of the JSON part of the stream.
Change the name to "nullptr" and add support for it in the
analyze-migration.py script. Arbitrarily use the name of the type as
the value of the field to avoid the script showing 0x30 or '0', which
could be confusing for readers.
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
migration/vmstate-types.c | 2 +-
scripts/analyze-migration.py | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
index e83bfccb9e..d70d573dbd 100644
--- a/migration/vmstate-types.c
+++ b/migration/vmstate-types.c
@@ -338,7 +338,7 @@ static int put_nullptr(QEMUFile *f, void *pv, size_t size,
}
const VMStateInfo vmstate_info_nullptr = {
- .name = "uint64",
+ .name = "nullptr",
.get = get_nullptr,
.put = put_nullptr,
};
diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
index fcda11f31d..134c25f20a 100755
--- a/scripts/analyze-migration.py
+++ b/scripts/analyze-migration.py
@@ -377,6 +377,8 @@ def read(self):
class VMSDFieldInt(VMSDFieldGeneric):
+ NULL_PTR_MARKER = 0x30
+
def __init__(self, desc, file):
super(VMSDFieldInt, self).__init__(desc, file)
self.size = int(desc['size'])
@@ -385,6 +387,16 @@ def __init__(self, desc, file):
self.udtype = '>u%d' % self.size
def __repr__(self):
+
+ # A NULL pointer is encoded in the stream as a '0' to
+ # disambiguate from a mere 0x0 value and avoid consumers
+ # trying to follow the NULL pointer. Displaying '0', 0x30 or
+ # 0x0 when analyzing the JSON debug stream could become
+ # confusing, so use an explicit term instead. The actual value
+ # in the stream was already validated by VMSDFieldNull.
+ if self.data == self.NULL_PTR_MARKER:
+ return "nullptr"
+
if self.data < 0:
return ('%s (%d)' % ((self.format % self.udata), self.data))
else:
@@ -417,6 +429,15 @@ def __init__(self, desc, file):
super(VMSDFieldIntLE, self).__init__(desc, file)
self.dtype = '<i%d' % self.size
+class VMSDFieldNull(VMSDFieldUInt):
+ def __init__(self, desc, file):
+ super(VMSDFieldUInt, self).__init__(desc, file)
+
+ def read(self):
+ super(VMSDFieldUInt, self).read()
+ assert(self.data == self.NULL_PTR_MARKER)
+ return self.data
+
class VMSDFieldBool(VMSDFieldGeneric):
def __init__(self, desc, file):
super(VMSDFieldBool, self).__init__(desc, file)
@@ -558,6 +579,7 @@ def getDict(self):
"bitmap" : VMSDFieldGeneric,
"struct" : VMSDFieldStruct,
"capability": VMSDFieldCap,
+ "nullptr": VMSDFieldNull,
"unknown" : VMSDFieldGeneric,
}
--
2.35.3On Thu, Jan 09, 2025 at 11:09:56AM -0300, Fabiano Rosas wrote:
> Rename vmstate_info_nullptr from "uint64_t" to "nullptr". This vmstate
> actually reads and writes just a byte, so the proper name would be
> uint8. However, since this is a marker for a NULL pointer, it's
> convenient to have a more explicit name that can be identified by the
> consumers of the JSON part of the stream.
>
> Change the name to "nullptr" and add support for it in the
> analyze-migration.py script. Arbitrarily use the name of the type as
> the value of the field to avoid the script showing 0x30 or '0', which
> could be confusing for readers.
>
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
> migration/vmstate-types.c | 2 +-
> scripts/analyze-migration.py | 22 ++++++++++++++++++++++
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
> index e83bfccb9e..d70d573dbd 100644
> --- a/migration/vmstate-types.c
> +++ b/migration/vmstate-types.c
> @@ -338,7 +338,7 @@ static int put_nullptr(QEMUFile *f, void *pv, size_t size,
> }
>
> const VMStateInfo vmstate_info_nullptr = {
> - .name = "uint64",
> + .name = "nullptr",
> .get = get_nullptr,
> .put = put_nullptr,
> };
> diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
> index fcda11f31d..134c25f20a 100755
> --- a/scripts/analyze-migration.py
> +++ b/scripts/analyze-migration.py
> @@ -377,6 +377,8 @@ def read(self):
>
>
> class VMSDFieldInt(VMSDFieldGeneric):
> + NULL_PTR_MARKER = 0x30
> +
> def __init__(self, desc, file):
> super(VMSDFieldInt, self).__init__(desc, file)
> self.size = int(desc['size'])
> @@ -385,6 +387,16 @@ def __init__(self, desc, file):
> self.udtype = '>u%d' % self.size
>
> def __repr__(self):
> +
> + # A NULL pointer is encoded in the stream as a '0' to
> + # disambiguate from a mere 0x0 value and avoid consumers
> + # trying to follow the NULL pointer. Displaying '0', 0x30 or
> + # 0x0 when analyzing the JSON debug stream could become
> + # confusing, so use an explicit term instead. The actual value
> + # in the stream was already validated by VMSDFieldNull.
> + if self.data == self.NULL_PTR_MARKER:
> + return "nullptr"
What happens if a real int field has value 0x30 which is not a marker?
Would it be wrongly represented as "nullptr"?
> +
> if self.data < 0:
> return ('%s (%d)' % ((self.format % self.udata), self.data))
> else:
> @@ -417,6 +429,15 @@ def __init__(self, desc, file):
> super(VMSDFieldIntLE, self).__init__(desc, file)
> self.dtype = '<i%d' % self.size
>
> +class VMSDFieldNull(VMSDFieldUInt):
> + def __init__(self, desc, file):
> + super(VMSDFieldUInt, self).__init__(desc, file)
> +
> + def read(self):
> + super(VMSDFieldUInt, self).read()
> + assert(self.data == self.NULL_PTR_MARKER)
> + return self.data
> +
> class VMSDFieldBool(VMSDFieldGeneric):
> def __init__(self, desc, file):
> super(VMSDFieldBool, self).__init__(desc, file)
> @@ -558,6 +579,7 @@ def getDict(self):
> "bitmap" : VMSDFieldGeneric,
> "struct" : VMSDFieldStruct,
> "capability": VMSDFieldCap,
> + "nullptr": VMSDFieldNull,
> "unknown" : VMSDFieldGeneric,
> }
>
> --
> 2.35.3
>
--
Peter Xu
Peter Xu <peterx@redhat.com> writes:
> On Thu, Jan 09, 2025 at 11:09:56AM -0300, Fabiano Rosas wrote:
>> Rename vmstate_info_nullptr from "uint64_t" to "nullptr". This vmstate
>> actually reads and writes just a byte, so the proper name would be
>> uint8. However, since this is a marker for a NULL pointer, it's
>> convenient to have a more explicit name that can be identified by the
>> consumers of the JSON part of the stream.
>>
>> Change the name to "nullptr" and add support for it in the
>> analyze-migration.py script. Arbitrarily use the name of the type as
>> the value of the field to avoid the script showing 0x30 or '0', which
>> could be confusing for readers.
>>
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>> migration/vmstate-types.c | 2 +-
>> scripts/analyze-migration.py | 22 ++++++++++++++++++++++
>> 2 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
>> index e83bfccb9e..d70d573dbd 100644
>> --- a/migration/vmstate-types.c
>> +++ b/migration/vmstate-types.c
>> @@ -338,7 +338,7 @@ static int put_nullptr(QEMUFile *f, void *pv, size_t size,
>> }
>>
>> const VMStateInfo vmstate_info_nullptr = {
>> - .name = "uint64",
>> + .name = "nullptr",
>> .get = get_nullptr,
>> .put = put_nullptr,
>> };
>> diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
>> index fcda11f31d..134c25f20a 100755
>> --- a/scripts/analyze-migration.py
>> +++ b/scripts/analyze-migration.py
>> @@ -377,6 +377,8 @@ def read(self):
>>
>>
>> class VMSDFieldInt(VMSDFieldGeneric):
>> + NULL_PTR_MARKER = 0x30
>> +
>> def __init__(self, desc, file):
>> super(VMSDFieldInt, self).__init__(desc, file)
>> self.size = int(desc['size'])
>> @@ -385,6 +387,16 @@ def __init__(self, desc, file):
>> self.udtype = '>u%d' % self.size
>>
>> def __repr__(self):
>> +
>> + # A NULL pointer is encoded in the stream as a '0' to
>> + # disambiguate from a mere 0x0 value and avoid consumers
>> + # trying to follow the NULL pointer. Displaying '0', 0x30 or
>> + # 0x0 when analyzing the JSON debug stream could become
>> + # confusing, so use an explicit term instead. The actual value
>> + # in the stream was already validated by VMSDFieldNull.
>> + if self.data == self.NULL_PTR_MARKER:
>> + return "nullptr"
>
> What happens if a real int field has value 0x30 which is not a marker?
> Would it be wrongly represented as "nullptr"?
>
Yes, better to not inherit from VMSDFieldInt then.
>> +
>> if self.data < 0:
>> return ('%s (%d)' % ((self.format % self.udata), self.data))
>> else:
>> @@ -417,6 +429,15 @@ def __init__(self, desc, file):
>> super(VMSDFieldIntLE, self).__init__(desc, file)
>> self.dtype = '<i%d' % self.size
>>
>> +class VMSDFieldNull(VMSDFieldUInt):
>> + def __init__(self, desc, file):
>> + super(VMSDFieldUInt, self).__init__(desc, file)
>> +
>> + def read(self):
>> + super(VMSDFieldUInt, self).read()
>> + assert(self.data == self.NULL_PTR_MARKER)
>> + return self.data
>> +
>> class VMSDFieldBool(VMSDFieldGeneric):
>> def __init__(self, desc, file):
>> super(VMSDFieldBool, self).__init__(desc, file)
>> @@ -558,6 +579,7 @@ def getDict(self):
>> "bitmap" : VMSDFieldGeneric,
>> "struct" : VMSDFieldStruct,
>> "capability": VMSDFieldCap,
>> + "nullptr": VMSDFieldNull,
>> "unknown" : VMSDFieldGeneric,
>> }
>>
>> --
>> 2.35.3
>>
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