* [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page
@ 2023-01-16 8:37 Dan Carpenter
2023-01-17 10:56 ` Jinank Jain
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2023-01-16 8:37 UTC (permalink / raw)
To: Tianyu.Lan; +Cc: linux-hyperv, Jinank Jain
Hello Tianyu Lan,
The patch faff44069ff5: "x86/hyperv: Add Write/Read MSR registers via
ghcb page" from Oct 25, 2021, leads to the following Smatch static
checker warning:
arch/x86/kernel/cpu/mshyperv.c:73 hv_get_non_nested_register()
error: uninitialized symbol 'value'.
arch/x86/kernel/cpu/mshyperv.c
63
64 #if IS_ENABLED(CONFIG_HYPERV)
65 u64 hv_get_non_nested_register(unsigned int reg)
66 {
67 u64 value;
68
69 if (hv_is_synic_reg(reg) && hv_isolation_type_snp())
70 hv_ghcb_msr_read(reg, &value);
^^^^^^
There are three places in hv_ghcb_msr_read() which don't initialize
value.
71 else
72 rdmsrl(reg, value);
--> 73 return value;
74 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page
2023-01-16 8:37 [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page Dan Carpenter
@ 2023-01-17 10:56 ` Jinank Jain
2023-01-17 11:00 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Jinank Jain @ 2023-01-17 10:56 UTC (permalink / raw)
To: Dan Carpenter, Tianyu.Lan; +Cc: linux-hyperv
Does making 0 as the default value makes sense?
Regards,
Jinank
On 1/16/2023 2:07 PM, Dan Carpenter wrote:
> Hello Tianyu Lan,
>
> The patch faff44069ff5: "x86/hyperv: Add Write/Read MSR registers via
> ghcb page" from Oct 25, 2021, leads to the following Smatch static
> checker warning:
>
> arch/x86/kernel/cpu/mshyperv.c:73 hv_get_non_nested_register()
> error: uninitialized symbol 'value'.
>
> arch/x86/kernel/cpu/mshyperv.c
> 63
> 64 #if IS_ENABLED(CONFIG_HYPERV)
> 65 u64 hv_get_non_nested_register(unsigned int reg)
> 66 {
> 67 u64 value;
> 68
> 69 if (hv_is_synic_reg(reg) && hv_isolation_type_snp())
> 70 hv_ghcb_msr_read(reg, &value);
> ^^^^^^
> There are three places in hv_ghcb_msr_read() which don't initialize
> value.
>
> 71 else
> 72 rdmsrl(reg, value);
> --> 73 return value;
> 74 }
>
> regards,
> dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page
2023-01-17 10:56 ` Jinank Jain
@ 2023-01-17 11:00 ` Dan Carpenter
2023-01-17 11:06 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2023-01-17 11:00 UTC (permalink / raw)
To: Jinank Jain; +Cc: Tianyu.Lan, linux-hyperv
On Tue, Jan 17, 2023 at 04:26:13PM +0530, Jinank Jain wrote:
> Does making 0 as the default value makes sense?
>
That would silence the warning, and most distros are going to enable
the config to zero it out anyway so it has no impact on runtime.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page
2023-01-17 11:00 ` Dan Carpenter
@ 2023-01-17 11:06 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2023-01-17 11:06 UTC (permalink / raw)
To: Jinank Jain; +Cc: Tianyu.Lan, linux-hyperv
On Tue, Jan 17, 2023 at 02:00:25PM +0300, Dan Carpenter wrote:
> On Tue, Jan 17, 2023 at 04:26:13PM +0530, Jinank Jain wrote:
> > Does making 0 as the default value makes sense?
> >
>
> That would silence the warning, and most distros are going to enable
> the config to zero it out anyway so it has no impact on runtime.
The config to zero out stack variables. CONFIG_INIT_STACK_ALL_ZERO.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-01-17 11:07 UTC | newest]
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2023-01-16 8:37 [bug report] x86/hyperv: Add Write/Read MSR registers via ghcb page Dan Carpenter
2023-01-17 10:56 ` Jinank Jain
2023-01-17 11:00 ` Dan Carpenter
2023-01-17 11:06 ` Dan Carpenter
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