From: Srikar Dronamraju srikar@linux.vnet.ibm.com
[ Upstream commit a21d1becaa3f17a97b933ffa677b526afc514ec5 ]
Introduce a static branch that would be set during boot if the OS happens to be a KVM guest. Subsequent checks to see if we are on KVM will rely on this static branch. This static branch would be used in vcpu_is_preempted() in a subsequent patch.
Signed-off-by: Srikar Dronamraju srikar@linux.vnet.ibm.com Acked-by: Waiman Long longman@redhat.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20201202050456.164005-4-srikar@linux.vnet.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/kvm_guest.h | 10 ++++++++++ arch/powerpc/include/asm/kvm_para.h | 2 +- arch/powerpc/kernel/firmware.c | 2 ++ 3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_guest.h b/arch/powerpc/include/asm/kvm_guest.h index d7749ecb30d49..2fca299f7e192 100644 --- a/arch/powerpc/include/asm/kvm_guest.h +++ b/arch/powerpc/include/asm/kvm_guest.h @@ -7,8 +7,18 @@ #define _ASM_POWERPC_KVM_GUEST_H_
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST) +#include <linux/jump_label.h> + +DECLARE_STATIC_KEY_FALSE(kvm_guest); + +static inline bool is_kvm_guest(void) +{ + return static_branch_unlikely(&kvm_guest); +} + bool check_kvm_guest(void); #else +static inline bool is_kvm_guest(void) { return false; } static inline bool check_kvm_guest(void) { return false; } #endif
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h index 6fba06b6cfdbc..abe1b5e82547b 100644 --- a/arch/powerpc/include/asm/kvm_para.h +++ b/arch/powerpc/include/asm/kvm_para.h @@ -14,7 +14,7 @@
static inline int kvm_para_available(void) { - return IS_ENABLED(CONFIG_KVM_GUEST) && check_kvm_guest(); + return IS_ENABLED(CONFIG_KVM_GUEST) && is_kvm_guest(); }
static inline unsigned int kvm_arch_para_features(void) diff --git a/arch/powerpc/kernel/firmware.c b/arch/powerpc/kernel/firmware.c index c3140c6084c93..c9e2819b095ab 100644 --- a/arch/powerpc/kernel/firmware.c +++ b/arch/powerpc/kernel/firmware.c @@ -22,6 +22,7 @@ EXPORT_SYMBOL_GPL(powerpc_firmware_features); #endif
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST) +DEFINE_STATIC_KEY_FALSE(kvm_guest); bool check_kvm_guest(void) { struct device_node *hyper_node; @@ -33,6 +34,7 @@ bool check_kvm_guest(void) if (!of_device_is_compatible(hyper_node, "linux,kvm")) return false;
+ static_branch_enable(&kvm_guest); return true; } #endif