26.01.2012 18:45, Kirill A. Shutemov wrote:
From: Thomas Renninger<[email protected]>
commit 5c2a9f06a9cd7194f884cdc88144866235dec07d upstream.
kvm -cpu host passes the original cpuid info to the guest.
Latest kvm version seem to return true for mwait_leaf cpuid
function on recent Intel CPUs. But it does not return mwait
C-states (mwait_substates), instead zero is returned.
[]
drivers/idle/intel_idle.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -321,7 +321,8 @@ static int intel_idle_probe(void)
cpuid(CPUID_MWAIT_LEAF,&eax,&ebx,&ecx,&mwait_substates);
if (!(ecx& CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
- !(ecx& CPUID5_ECX_INTERRUPT_BREAK))
+ !(ecx& CPUID5_ECX_INTERRUPT_BREAK) ||
+ !mwait_substates)
return -ENODEV;
It breaks build for me.
[]
CC drivers/idle/intel_idle.o
/home/space/kas/git/public/linux-3.0-mid/drivers/idle/intel_idle.c: In function
‘intel_idle_probe’:
/home/space/kas/git/public/linux-3.0-mid/drivers/idle/intel_idle.c:508:7:
error: ‘mwait_substates’ undeclared (first use in this function)
/home/space/kas/git/public/linux-3.0-mid/drivers/idle/intel_idle.c:508:7: note:
each undeclared identifier is reported only once for each function it appears in
make[3]: *** [drivers/idle/intel_idle.o] Error 1
Variable 'substates' hasn't renamed to 'mwait_substates' in 3.0.
See c423628 intel_idle: delete substates DEBUG modparam
I wonder why in my 3.0.18 this variable is properly defined
in the same file, in line 77:
...
74 /* intel_idle.max_cstate=0 disables driver */
75 static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
76
77 static unsigned int mwait_substates;
78
79 #define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF
...
Signed-off-by: Kirill A. Shutemov<[email protected]>
---
drivers/idle/intel_idle.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 15d72ca..a1aecc3 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -505,7 +505,7 @@ static int intel_idle_probe(void)
if (!(ecx& CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
!(ecx& CPUID5_ECX_INTERRUPT_BREAK) ||
- !mwait_substates)
+ !substates)
With this patch my build of 3.0.18 fails with "substates undeclared"
message...
if (substates == 0) /* can over-ride via modparam */
And I don't have this context line in my version.
It is 3.0 from kernel.org patched by patch-3.0.18.xz
Thanks,
/mjt
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