[PATCH v1] tools: use integer division in convert-legacy-stream

[PATCH v1] tools: use integer division in convert-legacy-stream

[Olaf Hering]

A single slash gives a float, a double slash gives an int.

    bitmap = unpack_exact("Q" * ((max_id/64) + 1))
TypeError: can't multiply sequence by non-int of type 'float'

This is broken for unknown reasons since 4.14.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/python/scripts/convert-legacy-stream | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)


diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream
index ca93a93848..a04c6e4165 100755
--- a/tools/python/scripts/convert-legacy-stream
+++ b/tools/python/scripts/convert-legacy-stream
@@ -163,7 +163,7 @@ def write_libxc_hvm_params(params):
         raise RuntimeError("Expected even length list of hvm parameters")
 
     write_record(libxc.REC_TYPE_hvm_params,
-                 pack(libxc.HVM_PARAMS_FORMAT, len(params) / 2, 0),
+                 pack(libxc.HVM_PARAMS_FORMAT, len(params) // 2, 0),
                  pack("Q" * len(params), *params))
 
 def write_libxc_static_data_end():
@@ -264,8 +264,8 @@ def read_pv_extended_info(vm):
                           (so_far - total_length, ))
 
 def read_pv_p2m_frames(vm):
-    fpp = 4096 / vm.width
-    p2m_frame_len = (vm.p2m_size - 1) / fpp + 1
+    fpp = 4096 // vm.width
+    p2m_frame_len = (vm.p2m_size - 1) // fpp + 1
 
     info("P2M frames: fpp %d, p2m_frame_len %d" % (fpp, p2m_frame_len))
     write_libxc_pv_p2m_frames(vm, unpack_ulongs(p2m_frame_len))
@@ -405,7 +405,7 @@ def read_chunks(vm):
                                   (max_id, legacy.MAX_VCPU_ID))
 
             vm.max_vcpu_id = max_id
-            bitmap = unpack_exact("Q" * ((max_id/64) + 1))
+            bitmap = unpack_exact("Q" * ((max_id//64) + 1))
 
             for idx, word in enumerate(bitmap):
                 bit_idx = 0

Re: [PATCH v1] tools: use integer division in convert-legacy-stream

[Andrew Cooper]

On 18/06/2021 10:31, Olaf Hering wrote:
> A single slash gives a float, a double slash gives an int.
>
>     bitmap = unpack_exact("Q" * ((max_id/64) + 1))
> TypeError: can't multiply sequence by non-int of type 'float'
>
> This is broken for unknown reasons since 4.14.

:(

This is a Py2 vs Py3 difference.

To not break Py2.7, we need "from __future__ import division" at the top
of the script, but I doubt this is the only script impacted.

>
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> ---
>  tools/python/scripts/convert-legacy-stream | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
>
> diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream
> index ca93a93848..a04c6e4165 100755
> --- a/tools/python/scripts/convert-legacy-stream
> +++ b/tools/python/scripts/convert-legacy-stream
> @@ -163,7 +163,7 @@ def write_libxc_hvm_params(params):
>          raise RuntimeError("Expected even length list of hvm parameters")
>  
>      write_record(libxc.REC_TYPE_hvm_params,
> -                 pack(libxc.HVM_PARAMS_FORMAT, len(params) / 2, 0),
> +                 pack(libxc.HVM_PARAMS_FORMAT, len(params) // 2, 0),
>                   pack("Q" * len(params), *params))
>  
>  def write_libxc_static_data_end():
> @@ -264,8 +264,8 @@ def read_pv_extended_info(vm):
>                            (so_far - total_length, ))
>  
>  def read_pv_p2m_frames(vm):
> -    fpp = 4096 / vm.width
> -    p2m_frame_len = (vm.p2m_size - 1) / fpp + 1
> +    fpp = 4096 // vm.width
> +    p2m_frame_len = (vm.p2m_size - 1) // fpp + 1
>  
>      info("P2M frames: fpp %d, p2m_frame_len %d" % (fpp, p2m_frame_len))
>      write_libxc_pv_p2m_frames(vm, unpack_ulongs(p2m_frame_len))
> @@ -405,7 +405,7 @@ def read_chunks(vm):
>                                    (max_id, legacy.MAX_VCPU_ID))
>  
>              vm.max_vcpu_id = max_id
> -            bitmap = unpack_exact("Q" * ((max_id/64) + 1))
> +            bitmap = unpack_exact("Q" * ((max_id//64) + 1))

While you're changing this, could we make it (max_id // 64) to fix the
style (which I clearly messed up first time around).

~Andrew

>  
>              for idx, word in enumerate(bitmap):
>                  bit_idx = 0
>

Re: [PATCH v1] tools: use integer division in convert-legacy-stream

[Olaf Hering]

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Am Fri, 18 Jun 2021 10:42:58 +0100
schrieb Andrew Cooper <andrew.cooper3@citrix.com>:

> This is a Py2 vs Py3 difference.

Indeed, my build wrapper changes every 'env python' to 'python3.4' in 4.14+ builds.
That explains why it happens to work with my 4.13 builds, which changes every 'env python' to 'python2.7'.

Olaf

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Re: [PATCH v1] tools: use integer division in convert-legacy-stream

[Olaf Hering]

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Am Fri, 18 Jun 2021 10:42:58 +0100
schrieb Andrew Cooper <andrew.cooper3@citrix.com>:

> This is a Py2 vs Py3 difference.

This script is not ready for python 3.

At a first glance it is the usual type confusion.
It seems the type 'bytearray' exists in both variants.
Perhaps stream_read() should return such an object, instead of either 'str' or 'bytes'.
I'm sure there are more pitfalls.

Olaf

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