2018-01-15 20:25:42

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] x86/jailhouse: fix building without X86_X2APIC

When CONFIG_X86_X2APIC is disabled, jailhouse fails to build:

arch/x86/kernel/jailhouse.c: In function 'jailhouse_get_smp_config':
arch/x86/kernel/jailhouse.c:73:3: error: 'x2apic_phys' undeclared (first use in this function); did you mean 'x2apic_mode'?

The code is protected by an appropriate x2apic_enabled() check that leads
to the assignment being optimized out without a link-time reference to
x2apic_phys, so we just lack a declaration.

Let's move x2apic_mode and x2apic_phys outside of the #ifdef together,
for consistency.

Fixes: 11c8dc419bbc ("x86/jailhouse: Enable APIC and SMP support")
Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/x86/include/asm/apic.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 98722773391d..0317d635d9ba 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -188,6 +188,8 @@ static inline void lapic_assign_system_vectors(void) { }
static inline void lapic_assign_legacy_vector(unsigned int i, bool r) { }
#endif /* !CONFIG_X86_LOCAL_APIC */

+extern int x2apic_mode;
+extern int x2apic_phys;
#ifdef CONFIG_X86_X2APIC
/*
* Make previous memory operations globally visible before
@@ -249,8 +251,6 @@ static inline u64 native_x2apic_icr_read(void)
return val;
}

-extern int x2apic_mode;
-extern int x2apic_phys;
extern void __init check_x2apic(void);
extern void x2apic_setup(void);
static inline int x2apic_enabled(void)
--
2.9.0


2018-01-16 01:25:20

by Dou Liyang

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

Hi Arnd,

At 01/16/2018 04:23 AM, Arnd Bergmann wrote:
> When CONFIG_X86_X2APIC is disabled, jailhouse fails to build:
>
> arch/x86/kernel/jailhouse.c: In function 'jailhouse_get_smp_config':
> arch/x86/kernel/jailhouse.c:73:3: error: 'x2apic_phys' undeclared (first use in this function); did you mean 'x2apic_mode'?
>
> The code is protected by an appropriate x2apic_enabled() check that leads
> to the assignment being optimized out without a link-time reference to
> x2apic_phys, so we just lack a declaration.
>
> Let's move x2apic_mode and x2apic_phys outside of the #ifdef together,
> for consistency.
>
> Fixes: 11c8dc419bbc ("x86/jailhouse: Enable APIC and SMP support")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> arch/x86/include/asm/apic.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index 98722773391d..0317d635d9ba 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -188,6 +188,8 @@ static inline void lapic_assign_system_vectors(void) { }
> static inline void lapic_assign_legacy_vector(unsigned int i, bool r) { }
> #endif /* !CONFIG_X86_LOCAL_APIC */
>
> +extern int x2apic_mode;
> +extern int x2apic_phys;
We can't do that, adding a macro for the X2APIC=n case is enough

Thanks,
dou

-------------------------8<----------------------

Subject: [PATCH] x86/apic: Add a macro named x2apic_phys for the
X2APIC=n case

The x86 system may build failed in the X2APIC=n case, due to the missing of
x2apic_phys.

So add a macro named x2apic_phys for the X2APIC=n case.

Signed-off-by: Dou Liyang <[email protected]>
---
arch/x86/include/asm/apic.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index a9e57f08bfa6..ca5940fb995a 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -264,7 +264,8 @@ static inline void x2apic_setup(void) { }
static inline int x2apic_enabled(void) { return 0; }

#define x2apic_mode (0)
-#define x2apic_supported() (0)
+#define x2apic_phys (0)
+#define x2apic_supported() (0)
#endif /* !CONFIG_X86_X2APIC */

struct irq_data;
--




2018-01-16 02:34:48

by Dou Liyang

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

Hi Arnd,

At 01/16/2018 09:25 AM, Dou Liyang wrote:
> Hi Arnd,
>
> At 01/16/2018 04:23 AM, Arnd Bergmann wrote:
>> When CONFIG_X86_X2APIC is disabled, jailhouse fails to build:
>>
>> arch/x86/kernel/jailhouse.c: In function 'jailhouse_get_smp_config':
>> arch/x86/kernel/jailhouse.c:73:3: error: 'x2apic_phys' undeclared
>> (first use in this function); did you mean 'x2apic_mode'?
>>
>> The code is protected by an appropriate x2apic_enabled() check that leads
>> to the assignment being optimized out without a link-time reference to
>> x2apic_phys, so we just lack a declaration.
>>
>> Let's move x2apic_mode and x2apic_phys outside of the #ifdef together,
>> for consistency.
>>
>> Fixes: 11c8dc419bbc ("x86/jailhouse: Enable APIC and SMP support")
>> Signed-off-by: Arnd Bergmann <[email protected]>
>> ---
>>   arch/x86/include/asm/apic.h | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
>> index 98722773391d..0317d635d9ba 100644
>> --- a/arch/x86/include/asm/apic.h
>> +++ b/arch/x86/include/asm/apic.h
>> @@ -188,6 +188,8 @@ static inline void
>> lapic_assign_system_vectors(void) { }
>>   static inline void lapic_assign_legacy_vector(unsigned int i, bool
>> r) { }
>>   #endif /* !CONFIG_X86_LOCAL_APIC */
>> +extern int x2apic_mode;
>> +extern int x2apic_phys;
> We can't do that, adding a macro for the X2APIC=n case is enough
>
I am sorry when I looked into your code in tip tree. I found this
measure is not true. please try the the following v2 patch.

The reason I don't want to expose the x2apic_mode and x2apic_phys is
that they may be misused in X2APIC=n case. So I create an interface to
wrap it. do you think so? ;-)

Thanks,
dou.
---
arch/x86/include/asm/apic.h | 10 +++++++++-
arch/x86/kernel/apic/apic.c | 2 +-
arch/x86/kernel/jailhouse.c | 2 +-
3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 98722773391d..ac25ac2e49af 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -251,6 +251,11 @@ static inline u64 native_x2apic_icr_read(void)

extern int x2apic_mode;
extern int x2apic_phys;
+static inline void apic_set_x2apic_phys(void)
+{
+ x2apic_phys = 1;
+}
+
extern void __init check_x2apic(void);
extern void x2apic_setup(void);
static inline int x2apic_enabled(void)
@@ -265,7 +270,10 @@ static inline void x2apic_setup(void) { }
static inline int x2apic_enabled(void) { return 0; }

#define x2apic_mode (0)
-#define x2apic_supported() (0)
+#define x2apic_phys (0)
+#define x2apic_supported() (0)
+
+static inline void apic_set_x2apic_phys(void){}
#endif /* !CONFIG_X86_X2APIC */

struct irq_data;
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 25ddf02598d2..440ff200104f 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1746,7 +1746,7 @@ static __init void try_to_enable_x2apic(int
remap_mode)
* without IR all CPUs can be addressed by IOAPIC/MSI
* only in physical mode
*/
- x2apic_phys = 1;
+ apic_set_x2apic_phys();
}
x2apic_enable();
}
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index d6d5976a9b51..ce62162efcf2 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -70,7 +70,7 @@ static void __init jailhouse_get_smp_config(unsigned
int early)
* We do not have access to IR inside Jailhouse non-root cells.
* So we have to run in physical mode.
*/
- x2apic_phys = 1;
+ apic_set_x2apic_phys();

/*
* This will trigger the switch to apic_x2apic_phys.
--
> Thanks,
>     dou
>
> -------------------------8<----------------------
>
> Subject: [PATCH] x86/apic: Add a macro named x2apic_phys for the
> X2APIC=n case
>
> The x86 system may build failed in the X2APIC=n case, due to the missing of
> x2apic_phys.
>
> So add a macro named x2apic_phys for the X2APIC=n case.
>
> Signed-off-by: Dou Liyang <[email protected]>
> ---
>  arch/x86/include/asm/apic.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index a9e57f08bfa6..ca5940fb995a 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -264,7 +264,8 @@ static inline void x2apic_setup(void) { }
>  static inline int x2apic_enabled(void) { return 0; }
>
>  #define x2apic_mode        (0)
> -#define    x2apic_supported()    (0)
> +#define x2apic_phys        (0)
> +#define x2apic_supported()    (0)
>  #endif /* !CONFIG_X86_X2APIC */
>
>  struct irq_data;


2018-01-16 07:21:23

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

On Tue, Jan 16, 2018 at 3:34 AM, Dou Liyang <[email protected]> wrote:
> At 01/16/2018 09:25 AM, Dou Liyang wrote:

>>> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
>>> index 98722773391d..0317d635d9ba 100644
>>> --- a/arch/x86/include/asm/apic.h
>>> +++ b/arch/x86/include/asm/apic.h
>>> @@ -188,6 +188,8 @@ static inline void lapic_assign_system_vectors(void)
>>> { }
>>> static inline void lapic_assign_legacy_vector(unsigned int i, bool r) {
>>> }
>>> #endif /* !CONFIG_X86_LOCAL_APIC */
>>> +extern int x2apic_mode;
>>> +extern int x2apic_phys;
>>
>> We can't do that, adding a macro for the X2APIC=n case is enough
>>
> I am sorry when I looked into your code in tip tree. I found this
> measure is not true. please try the the following v2 patch.
>
> The reason I don't want to expose the x2apic_mode and x2apic_phys is
> that they may be misused in X2APIC=n case. So I create an interface to
> wrap it. do you think so? ;-)

I'm not sure I follow what the intention of that is. If you want to hide
those two variables, maybe make them 'static' and remove the extern
declarations?

> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index 98722773391d..ac25ac2e49af 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -251,6 +251,11 @@ static inline u64 native_x2apic_icr_read(void)
>
> extern int x2apic_mode;
> extern int x2apic_phys;
> +static inline void apic_set_x2apic_phys(void)
> +{
> + x2apic_phys = 1;
> +}
> +
> extern void __init check_x2apic(void);
> extern void x2apic_setup(void);
> static inline int x2apic_enabled(void)
> @@ -265,7 +270,10 @@ static inline void x2apic_setup(void) { }
> static inline int x2apic_enabled(void) { return 0; }
>
> #define x2apic_mode (0)
> -#define x2apic_supported() (0)
> +#define x2apic_phys (0)
> +#define x2apic_supported() (0)
> +
> +static inline void apic_set_x2apic_phys(void){}
> #endif /* !CONFIG_X86_X2APIC */
>
> struct irq_data;

I see nothing wrong it with this, but also don't see anything it does
that improves the interface.

Arnd

2018-01-16 08:17:47

by Dou Liyang

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

Hi Arnd,

[...]
>> The reason I don't want to expose the x2apic_mode and x2apic_phys is
>> that they may be misused in X2APIC=n case. So I create an interface to
>> wrap it. do you think so? ;-)
>
> I'm not sure I follow what the intention of that is. If you want to hide

My purpose of that is hiding the variables in X2APIC=n case.

> those two variables, maybe make them 'static' and remove the extern
> declarations?
>

Yes, that's what I really want, But due to the simple "x2apic_phys= 1"
operation, doing that may be too fat, I guess.

>> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
>> index 98722773391d..ac25ac2e49af 100644
>> --- a/arch/x86/include/asm/apic.h
>> +++ b/arch/x86/include/asm/apic.h
>> @@ -251,6 +251,11 @@ static inline u64 native_x2apic_icr_read(void)
>>
>> extern int x2apic_mode;
>> extern int x2apic_phys;
>> +static inline void apic_set_x2apic_phys(void)
>> +{
>> + x2apic_phys = 1;
>> +}
>> +
>> extern void __init check_x2apic(void);
>> extern void x2apic_setup(void);
>> static inline int x2apic_enabled(void)
>> @@ -265,7 +270,10 @@ static inline void x2apic_setup(void) { }
>> static inline int x2apic_enabled(void) { return 0; }
>>
>> #define x2apic_mode (0)
>> -#define x2apic_supported() (0)
>> +#define x2apic_phys (0)
>> +#define x2apic_supported() (0)
>> +
>> +static inline void apic_set_x2apic_phys(void){}
>> #endif /* !CONFIG_X86_X2APIC */
>>
>> struct irq_data;
>
> I see nothing wrong it with this, but also don't see anything it does
> that improves the interface.
>

Another way we can choice is wrap the code with "CONFIG_X86_X2APIC".

Thanks,
dou
--------------------------------8<------------------------------------
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index d6d5976a9b51..d4aee43c8912 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -65,6 +65,7 @@ static void __init jailhouse_get_smp_config(unsigned
int early)
};
unsigned int cpu;

+#ifdef CONFIG_X86_X2APIC
if (x2apic_enabled()) {
/*
* We do not have access to IR inside Jailhouse
non-root cells.
@@ -79,6 +80,7 @@ static void __init jailhouse_get_smp_config(unsigned
int early)
*/
default_acpi_madt_oem_check("", "");
}
+#endif

register_lapic_address(0xfee00000);

> Arnd
>
>
>


2018-01-16 08:50:20

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

On Tue, Jan 16, 2018 at 9:17 AM, Dou Liyang <[email protected]> wrote:
> Hi Arnd,
>
> [...]
>>>
>>> The reason I don't want to expose the x2apic_mode and x2apic_phys is
>>> that they may be misused in X2APIC=n case. So I create an interface to
>>> wrap it. do you think so? ;-)
>>
>>
>> I'm not sure I follow what the intention of that is. If you want to hide
>
>
> My purpose of that is hiding the variables in X2APIC=n case.

But why? I'd say either hide them all the time, or don't hide them at all.

>> I see nothing wrong it with this, but also don't see anything it does
>> that improves the interface.
>>
>
> Another way we can choice is wrap the code with "CONFIG_X86_X2APIC".
>

But why? That just makes perfectly reasonably code uglier. Generally
speaking, compiler conditionals are better than preprocessor conditionals
for this, as they are easier to read and provide better compile-time coverage
when things go wrong, such as the missing declaration.

Arnd

> --------------------------------8<------------------------------------
> diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
> index d6d5976a9b51..d4aee43c8912 100644
> --- a/arch/x86/kernel/jailhouse.c
> +++ b/arch/x86/kernel/jailhouse.c
> @@ -65,6 +65,7 @@ static void __init jailhouse_get_smp_config(unsigned int
> early)
> };
> unsigned int cpu;
>
> +#ifdef CONFIG_X86_X2APIC
> if (x2apic_enabled()) {
> /*
> * We do not have access to IR inside Jailhouse non-root
> cells.
> @@ -79,6 +80,7 @@ static void __init jailhouse_get_smp_config(unsigned int
> early)
> */
> default_acpi_madt_oem_check("", "");
> }
> +#endif

2018-01-16 11:03:02

by Dou Liyang

[permalink] [raw]
Subject: Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

Hi Arnd,

At 01/16/2018 04:50 PM, Arnd Bergmann wrote:
> On Tue, Jan 16, 2018 at 9:17 AM, Dou Liyang <[email protected]> wrote:
>> Hi Arnd,
>>
>> [...]
>>>>
>>>> The reason I don't want to expose the x2apic_mode and x2apic_phys is
>>>> that they may be misused in X2APIC=n case. So I create an interface to
>>>> wrap it. do you think so? ;-)
>>>
>>>
>>> I'm not sure I follow what the intention of that is. If you want to hide
>>
>>
>> My purpose of that is hiding the variables in X2APIC=n case.
>
> But why? I'd say either hide them all the time, or don't hide them at all.
>

In this case, I prefer to hide them all the time.

>>> I see nothing wrong it with this, but also don't see anything it does
>>> that improves the interface.
>>>
>>
>> Another way we can choice is wrap the code with "CONFIG_X86_X2APIC".
>>
>
> But why? That just makes perfectly reasonably code uglier. Generally
> speaking, compiler conditionals are better than preprocessor conditionals
> for this, as they are easier to read and provide better compile-time coverage
> when things go wrong, such as the missing declaration.
>

Yes, Indeed. Thank you for telling me that.

Thanks,
dou.