Commit a21d1bec authored by Srikar Dronamraju's avatar Srikar Dronamraju Committed by Michael Ellerman

powerpc: Reintroduce is_kvm_guest() as a fast-path check

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: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202050456.164005-4-srikar@linux.vnet.ibm.com
parent 16520a85
......@@ -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
......
......@@ -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)
......
......@@ -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
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