* [RFC PATCH-for-7.0] hw/i386/amd_iommu: Fix maybe-uninitialized error with GCC 12
@ 2022-03-18 0:41 Philippe Mathieu-Daudé
2022-03-18 14:03 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 3+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-03-18 0:41 UTC (permalink / raw)
To: qemu-devel
Cc: Eduardo Habkost, Michael S. Tsirkin, Richard Henderson,
Philippe Mathieu-Daudé,
Paolo Bonzini
From: Philippe Mathieu-Daudé <f4bug@amsat.org>
Initialize 'oldlevel' early to avoid on Debian/sid:
FAILED: libqemu-x86_64-softmmu.fa.p/hw_i386_amd_iommu.c.o
In function 'pte_get_page_mask',
inlined from 'amdvi_page_walk' at hw/i386/amd_iommu.c:945:25,
inlined from 'amdvi_do_translate' at hw/i386/amd_iommu.c:989:5,
inlined from 'amdvi_translate' at hw/i386/amd_iommu.c:1038:5:
hw/i386/amd_iommu.c:877:38: error: 'oldlevel' may be used uninitialized [-Werror=maybe-uninitialized]
877 | return ~((1UL << ((oldlevel * 9) + 3)) - 1);
| ~~~~~~~~~~~~~~~~^~~~
hw/i386/amd_iommu.c: In function 'amdvi_translate':
hw/i386/amd_iommu.c:906:41: note: 'oldlevel' was declared here
906 | unsigned level, present, pte_perms, oldlevel;
| ^~~~~~~~
cc1: all warnings being treated as errors
Having:
$ gcc --version
gcc (Debian 12-20220313-1) 12.0.1 20220314 (experimental)
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
hw/i386/amd_iommu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 4d13d8e697..b6d299f964 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -904,6 +904,7 @@ static void amdvi_page_walk(AMDVIAddressSpace *as, uint64_t *dte,
/* make sure the DTE has TV = 1 */
if (pte & AMDVI_DEV_TRANSLATION_VALID) {
level = get_pte_translation_mode(pte);
+ oldlevel = level;
if (level >= 7) {
trace_amdvi_mode_invalid(level, addr);
return;
--
2.35.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RFC PATCH-for-7.0] hw/i386/amd_iommu: Fix maybe-uninitialized error with GCC 12
2022-03-18 0:41 [RFC PATCH-for-7.0] hw/i386/amd_iommu: Fix maybe-uninitialized error with GCC 12 Philippe Mathieu-Daudé
@ 2022-03-18 14:03 ` Philippe Mathieu-Daudé
2022-03-21 14:40 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Philippe Mathieu-Daudé @ 2022-03-18 14:03 UTC (permalink / raw)
To: qemu-devel, qemu-trivial
Cc: Eduardo Habkost, Michael S. Tsirkin, Richard Henderson,
Philippe Mathieu-Daudé,
Paolo Bonzini
+qemu-trivial@
On 18/3/22 01:41, Philippe Mathieu-Daudé wrote:
> From: Philippe Mathieu-Daudé <f4bug@amsat.org>
>
> Initialize 'oldlevel' early to avoid on Debian/sid:
>
> FAILED: libqemu-x86_64-softmmu.fa.p/hw_i386_amd_iommu.c.o
> In function 'pte_get_page_mask',
> inlined from 'amdvi_page_walk' at hw/i386/amd_iommu.c:945:25,
> inlined from 'amdvi_do_translate' at hw/i386/amd_iommu.c:989:5,
> inlined from 'amdvi_translate' at hw/i386/amd_iommu.c:1038:5:
> hw/i386/amd_iommu.c:877:38: error: 'oldlevel' may be used uninitialized [-Werror=maybe-uninitialized]
> 877 | return ~((1UL << ((oldlevel * 9) + 3)) - 1);
> | ~~~~~~~~~~~~~~~~^~~~
> hw/i386/amd_iommu.c: In function 'amdvi_translate':
> hw/i386/amd_iommu.c:906:41: note: 'oldlevel' was declared here
> 906 | unsigned level, present, pte_perms, oldlevel;
> | ^~~~~~~~
> cc1: all warnings being treated as errors
>
> Having:
>
> $ gcc --version
> gcc (Debian 12-20220313-1) 12.0.1 20220314 (experimental)
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> hw/i386/amd_iommu.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
> index 4d13d8e697..b6d299f964 100644
> --- a/hw/i386/amd_iommu.c
> +++ b/hw/i386/amd_iommu.c
> @@ -904,6 +904,7 @@ static void amdvi_page_walk(AMDVIAddressSpace *as, uint64_t *dte,
> /* make sure the DTE has TV = 1 */
> if (pte & AMDVI_DEV_TRANSLATION_VALID) {
> level = get_pte_translation_mode(pte);
> + oldlevel = level;
> if (level >= 7) {
> trace_amdvi_mode_invalid(level, addr);
> return;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC PATCH-for-7.0] hw/i386/amd_iommu: Fix maybe-uninitialized error with GCC 12
2022-03-18 14:03 ` Philippe Mathieu-Daudé
@ 2022-03-21 14:40 ` Paolo Bonzini
0 siblings, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2022-03-21 14:40 UTC (permalink / raw)
To: Philippe Mathieu-Daudé, qemu-devel
Cc: Eduardo Habkost, Richard Henderson, Philippe Mathieu-Daudé,
Michael S. Tsirkin
On 3/18/22 15:03, Philippe Mathieu-Daudé wrote:
> +qemu-trivial@
Laurent,
please do not merge this patch as I've sent a replacement and I'll take
care of merging it.
Paolo
> On 18/3/22 01:41, Philippe Mathieu-Daudé wrote:
>> From: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>
>> Initialize 'oldlevel' early to avoid on Debian/sid:
>>
>> FAILED: libqemu-x86_64-softmmu.fa.p/hw_i386_amd_iommu.c.o
>> In function 'pte_get_page_mask',
>> inlined from 'amdvi_page_walk' at hw/i386/amd_iommu.c:945:25,
>> inlined from 'amdvi_do_translate' at hw/i386/amd_iommu.c:989:5,
>> inlined from 'amdvi_translate' at hw/i386/amd_iommu.c:1038:5:
>> hw/i386/amd_iommu.c:877:38: error: 'oldlevel' may be used
>> uninitialized [-Werror=maybe-uninitialized]
>> 877 | return ~((1UL << ((oldlevel * 9) + 3)) - 1);
>> | ~~~~~~~~~~~~~~~~^~~~
>> hw/i386/amd_iommu.c: In function 'amdvi_translate':
>> hw/i386/amd_iommu.c:906:41: note: 'oldlevel' was declared here
>> 906 | unsigned level, present, pte_perms, oldlevel;
>> | ^~~~~~~~
>> cc1: all warnings being treated as errors
>>
>> Having:
>>
>> $ gcc --version
>> gcc (Debian 12-20220313-1) 12.0.1 20220314 (experimental)
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>> hw/i386/amd_iommu.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
>> index 4d13d8e697..b6d299f964 100644
>> --- a/hw/i386/amd_iommu.c
>> +++ b/hw/i386/amd_iommu.c
>> @@ -904,6 +904,7 @@ static void amdvi_page_walk(AMDVIAddressSpace *as,
>> uint64_t *dte,
>> /* make sure the DTE has TV = 1 */
>> if (pte & AMDVI_DEV_TRANSLATION_VALID) {
>> level = get_pte_translation_mode(pte);
>> + oldlevel = level;
>> if (level >= 7) {
>> trace_amdvi_mode_invalid(level, addr);
>> return;
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-18 0:41 [RFC PATCH-for-7.0] hw/i386/amd_iommu: Fix maybe-uninitialized error with GCC 12 Philippe Mathieu-Daudé
2022-03-18 14:03 ` Philippe Mathieu-Daudé
2022-03-21 14:40 ` Paolo Bonzini
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