The existence of virt_spin_lock_key is contingent only on CONFIG_PARAVIRT, not 
on CONFIG_PARAVIRT_SPINLOCKS.

As a result, a kernel with CONFIG_PARAVIRT enabled, but CONFIG_PARAVIRT_SPINLOCKS
disabled will end up disabling queued spinlocks when running on bare metal.

Making the disabling of virt_spin_lock_key contingent on CONFIG_PARAVIRT, which 
controls whether the key exists, results in queued spinlocks being enabled on
bare metal again.

Signed-off-by: Rik van Riel <riel@surriel.com>
Cc: stable@vger.kernel.org
Fixes: ce0a1b608bfc ("x86/paravirt: Silence unused native_pv_lock_init() function warning")
---
 arch/x86/kernel/paravirt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 5358d43886ad..dd542a9c6667 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -55,7 +55,7 @@ DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
 
 void __init native_pv_lock_init(void)
 {
-	if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) &&
+	if (IS_ENABLED(CONFIG_PARAVIRT) &&
 	    !boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		static_branch_disable(&virt_spin_lock_key);
 }
-- 
2.45.2

On 15.07.24 19:18, Rik van Riel wrote:
> The existence of virt_spin_lock_key is contingent only on CONFIG_PARAVIRT, not
> on CONFIG_PARAVIRT_SPINLOCKS.
> 
> As a result, a kernel with CONFIG_PARAVIRT enabled, but CONFIG_PARAVIRT_SPINLOCKS
> disabled will end up disabling queued spinlocks when running on bare metal.
> 
> Making the disabling of virt_spin_lock_key contingent on CONFIG_PARAVIRT, which
> controls whether the key exists, results in queued spinlocks being enabled on
> bare metal again.
> 
> Signed-off-by: Rik van Riel <riel@surriel.com>
> Cc: stable@vger.kernel.org
> Fixes: ce0a1b608bfc ("x86/paravirt: Silence unused native_pv_lock_init() function warning")

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen