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

From: Dou Liyang
Date: Mon Jan 15 2018 - 21:34:54 EST


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 <arnd@xxxxxxxx>
---
 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,
ÂÂÂÂdou

-------------------------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 <douly.fnst@xxxxxxxxxxxxxx>
---
Âarch/x86/include/asm/apic.h | 3 ++-
Â1 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) { }
Âstatic inline int x2apic_enabled(void) { return 0; }

Â#define x2apic_modeÂÂÂÂÂÂÂ (0)
-#defineÂÂÂ x2apic_supported()ÂÂÂ (0)
+#define x2apic_physÂÂÂÂÂÂÂ (0)
+#define x2apic_supported()ÂÂÂ (0)
Â#endif /* !CONFIG_X86_X2APIC */

Âstruct irq_data;