Messages in this thread Patch in this message | | | From | Srikar Dronamraju <> | Subject | [PATCH 3/4] powerpc: Reintroduce is_kvm_guest in a new avatar | Date | Wed, 28 Oct 2020 18:05:11 +0530 |
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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> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Cc: LKML <linux-kernel@vger.kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Waiman Long <longman@redhat.com> Cc: Phil Auld <pauld@redhat.com> --- arch/powerpc/include/asm/kvm_guest.h | 10 ++++++++++ arch/powerpc/include/asm/kvm_para.h | 2 +- arch/powerpc/kernel/firmware.c | 3 +++ 3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_guest.h b/arch/powerpc/include/asm/kvm_guest.h index ba8291e02ba9..627ba272e781 100644 --- a/arch/powerpc/include/asm/kvm_guest.h +++ b/arch/powerpc/include/asm/kvm_guest.h @@ -7,8 +7,18 @@ #define __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 61243267d4cf..28498fc573f2 100644 --- a/arch/powerpc/kernel/firmware.c +++ b/arch/powerpc/kernel/firmware.c @@ -14,6 +14,7 @@ #include <linux/of.h> #include <asm/firmware.h> +#include <asm/kvm_guest.h> #ifdef CONFIG_PPC64 unsigned long powerpc_firmware_features __read_mostly; @@ -21,6 +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; @@ -32,6 +34,7 @@ bool check_kvm_guest(void) if (!of_device_is_compatible(hyper_node, "linux,kvm")) return 0; + static_branch_enable(&kvm_guest); return 1; } #endif -- 2.18.4
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