Re: [PATCH 3/6] contrib/plugins/hwprofile: fix warning when compiling on 32bits host

["Alex Bennée" <alex.bennee@linaro.org>]

Thomas Huth <thuth@redhat.com> writes:

> On 15/08/2024 01.36, Pierrick Bouvier wrote:
>> Found on debian stable (i386).
>> ../contrib/plugins/hwprofile.c: In function 'new_location':
>> ../contrib/plugins/hwprofile.c:172:32: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>    172 |     g_hash_table_insert(table, (gpointer) off_or_pc, loc);
>>        |                                ^
>> ../contrib/plugins/hwprofile.c: In function 'vcpu_haddr':
>> ../contrib/plugins/hwprofile.c:227:19: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
>>    227 |             off = (uint64_t) udata;
>>        |                   ^
>> ../contrib/plugins/hwprofile.c:232:62: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>    232 |                                                              (gpointer) off);
>>        |                                                              ^
>> ../contrib/plugins/hwprofile.c: In function 'vcpu_tb_trans':
>> ../contrib/plugins/hwprofile.c:250:26: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>    250 |         gpointer udata = (gpointer) (source ? qemu_plugin_insn_vaddr(insn) : 0);
>>        |
>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
>> ---
>>   contrib/plugins/hwprofile.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>> diff --git a/contrib/plugins/hwprofile.c
>> b/contrib/plugins/hwprofile.c
>> index 739ac0c66b5..ee94a74ad94 100644
>> --- a/contrib/plugins/hwprofile.c
>> +++ b/contrib/plugins/hwprofile.c
>> @@ -165,7 +165,7 @@ static DeviceCounts *new_count(const char *name, uint64_t base)
>>       return count;
>>   }
>>   -static IOLocationCounts *new_location(GHashTable *table, uint64_t
>> off_or_pc)
>> +static IOLocationCounts *new_location(GHashTable *table, uintptr_t off_or_pc)
>>   {
>>       IOLocationCounts *loc = g_new0(IOLocationCounts, 1);
>>       loc->off_or_pc = off_or_pc;
>> @@ -201,7 +201,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
>>           return;
>>       } else {
>>           const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
>> -        uint64_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
>> +        uintptr_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
>
> qemu_plugin_hwaddr_phys_addr() returns an uint64_t, so this looks
> wrong to me.

It is. However it just goes to show you should be expecting to
instrument 64 bit code with a 32 bit host because you can't do pointer
stuffing tricks like this.

Maybe we could just disable plugins on 32 bit hosts?

>
>  Thomas

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro