From: Srikar Dronamraju <srikar@linux.vnet.ibm.com> stable inclusion from stable-5.10.80 commit e01a4d7560b64791c350cd531b84a6a53ba6325b bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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> Signed-off-by: Chen Jun <chenjun102@huawei.com> Reviewed-by: Weilong Chen <chenweilong@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- 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 d7749ecb30d4..2fca299f7e19 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 6fba06b6cfdb..abe1b5e82547 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 c3140c6084c9..c9e2819b095a 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 -- 2.20.1