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With virt_spin_lock() being guarded by a static key the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. V2: - use static key instead of making virt_spin_lock() a pvops function Juergen Gross

With virt_spin_lock() being guarded by a static key the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. V2: - use static key instead of making virt_spin_lock() a pvops function Juergen Gross

...pv_lock_ops = { #endif /* SMP */ }; EXPORT_SYMBOL(pv_lock_ops); + +void __init native_pv_lock_init(void) +{ + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) + static_branch_disable(&virt_spin_lock_key); +} diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 54b9e89d4d6b..21500d3ba359 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -77,6 +77,7 @@ #include <asm/i8259.h> #include <asm/realmode.h> #include <asm/misc.h> +#include <asm/qspinlock.h> /* Number of siblings per CPU package */ int smp_num_siblings = 1; @@ -1381,6 +1...

...EXPORT_SYMBOL(pv_lock_ops); > + > +void __init native_pv_lock_init(void) > +{ > + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) > + static_branch_disable(&virt_spin_lock_key); > +} > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c > index 54b9e89d4d6b..21500d3ba359 100644 > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -77,6 +77,7 @@ > #include <asm/i8259.h> > #include <asm/realmode.h> > #include <asm/misc.h> > +#include <asm/qspinlock.h> > > /* Number of siblings per CPU packag...

...EXPORT_SYMBOL(pv_lock_ops); > + > +void __init native_pv_lock_init(void) > +{ > + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) > + static_branch_disable(&virt_spin_lock_key); > +} > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c > index 54b9e89d4d6b..21500d3ba359 100644 > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -77,6 +77,7 @@ > #include <asm/i8259.h> > #include <asm/realmode.h> > #include <asm/misc.h> > +#include <asm/qspinlock.h> > > /* Number of siblings per CPU packag...

...f /* SMP */ }; EXPORT_SYMBOL(pv_lock_ops); + +void __init native_pv_lock_init(void) +{ + if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) + pv_lock_ops.virt_spin_lock = + __PV_IS_CALLEE_SAVE(_paravirt_false); +} diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 54b9e89d4d6b..21500d3ba359 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -77,6 +77,7 @@ #include <asm/i8259.h> #include <asm/realmode.h> #include <asm/misc.h> +#include <asm/qspinlock.h> /* Number of siblings per CPU package */ int smp_num_siblings = 1; @@ -1381,6 +1...

With virt_spin_lock() being guarded by a static key the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. V3: - remove test for hypervisor environment from virt_spin_lock(9 as suggested by

With virt_spin_lock() being guarded by a static key the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. V3: - remove test for hypervisor environment from virt_spin_lock(9 as suggested by

With virt_spin_lock() being a pvops function the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. Juergen Gross (4): paravirt: add generic _paravirt_false() function paravirt: switch

With virt_spin_lock() being a pvops function the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. Juergen Gross (4): paravirt: add generic _paravirt_false() function paravirt: switch