KVM SPE emulation requires at least one physical CPU to support SPE.
Initialize the cpumask of PEs that support SPE the first time
KVM_CAP_ARM_SPE is queried or when the first virtual machine is created,
whichever comes first.
Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
---
arch/arm64/include/asm/kvm_spe.h | 26 ++++++++++++++++++++++++++
arch/arm64/kvm/Makefile | 1 +
arch/arm64/kvm/arm.c | 4 ++++
arch/arm64/kvm/spe.c | 32 ++++++++++++++++++++++++++++++++
4 files changed, 63 insertions(+)
create mode 100644 arch/arm64/include/asm/kvm_spe.h
create mode 100644 arch/arm64/kvm/spe.c
diff --git a/arch/arm64/include/asm/kvm_spe.h b/arch/arm64/include/asm/kvm_spe.h
new file mode 100644
index 000000000000..328115ce0b48
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_spe.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 - ARM Ltd
+ */
+
+#ifndef __ARM64_KVM_SPE_H__
+#define __ARM64_KVM_SPE_H__
+
+#ifdef CONFIG_KVM_ARM_SPE
+DECLARE_STATIC_KEY_FALSE(kvm_spe_available);
+
+static __always_inline bool kvm_supports_spe(void)
+{
+ return static_branch_likely(&kvm_spe_available);
+}
+
+void kvm_spe_init_supported_cpus(void);
+void kvm_spe_vm_init(struct kvm *kvm);
+#else
+#define kvm_supports_spe() (false)
+
+static inline void kvm_spe_init_supported_cpus(void) {}
+static inline void kvm_spe_vm_init(struct kvm *kvm) {}
+#endif /* CONFIG_KVM_ARM_SPE */
+
+#endif /* __ARM64_KVM_SPE_H__ */
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 989bb5dad2c8..86092a0f8367 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -25,3 +25,4 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
vgic/vgic-its.o vgic/vgic-debug.o
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o
+kvm-$(CONFIG_KVM_ARM_SPE) += spe.o
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 22544eb367f3..82cb7b5b3b45 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -35,6 +35,7 @@
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>
+#include <asm/kvm_spe.h>
#include <asm/kvm_emulate.h>
#include <asm/sections.h>
@@ -180,6 +181,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
set_default_spectre(kvm);
+ kvm_spe_vm_init(kvm);
+
return ret;
out_free_stage2_pgd:
kvm_free_stage2_pgd(&kvm->arch.mmu);
@@ -305,6 +308,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = 1;
break;
case KVM_CAP_ARM_SPE:
+ kvm_spe_init_supported_cpus();
r = 0;
break;
default:
diff --git a/arch/arm64/kvm/spe.c b/arch/arm64/kvm/spe.c
new file mode 100644
index 000000000000..83f92245f881
--- /dev/null
+++ b/arch/arm64/kvm/spe.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 - ARM Ltd
+ */
+
+#include <linux/cpumask.h>
+#include <linux/kvm_host.h>
+#include <linux/perf/arm_pmu.h>
+
+#include <asm/kvm_spe.h>
+
+DEFINE_STATIC_KEY_FALSE(kvm_spe_available);
+
+static const cpumask_t *supported_cpus;
+
+void kvm_spe_init_supported_cpus(void)
+{
+ if (likely(supported_cpus))
+ return;
+
+ supported_cpus = arm_spe_pmu_supported_cpus();
+ BUG_ON(!supported_cpus);
+
+ if (!cpumask_empty(supported_cpus))
+ static_branch_enable(&kvm_spe_available);
+}
+
+void kvm_spe_vm_init(struct kvm *kvm)
+{
+ /* Set supported_cpus if it isn't already initialized. */
+ kvm_spe_init_supported_cpus();
+}
--
2.33.0
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