[PATCH v5 07/69] KVM: arm64: nv: Introduce nested virtualization VCPU feature
From: Marc Zyngier <maz@kernel.org>
Date: 2021-11-29 20:06:57
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: Christoffer Dall <redacted> Introduce the feature bit and a primitive that checks if the feature is set behind a static key check based on the cpus_have_const_cap check. Checking nested_virt_in_use() on systems without nested virt enabled should have neglgible overhead. We don't yet allow userspace to actually set this feature. Signed-off-by: Christoffer Dall <redacted> Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/kvm_nested.h | 14 ++++++++++++++ arch/arm64/include/uapi/asm/kvm.h | 1 + 2 files changed, 15 insertions(+) create mode 100644 arch/arm64/include/asm/kvm_nested.h
diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
new file mode 100644
index 000000000000..1028ac65a897
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_nested.h@@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ARM64_KVM_NESTED_H +#define __ARM64_KVM_NESTED_H + +#include <linux/kvm_host.h> + +static inline bool nested_virt_in_use(const struct kvm_vcpu *vcpu) +{ + return (!__is_defined(__KVM_NVHE_HYPERVISOR__) && + cpus_have_final_cap(ARM64_HAS_NESTED_VIRT) && + test_bit(KVM_ARM_VCPU_HAS_EL2, vcpu->arch.features)); +} + +#endif /* __ARM64_KVM_NESTED_H */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index b3edde68bc3e..395a4c039bcc 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h@@ -106,6 +106,7 @@ struct kvm_regs { #define KVM_ARM_VCPU_SVE 4 /* enable SVE for this CPU */ #define KVM_ARM_VCPU_PTRAUTH_ADDRESS 5 /* VCPU uses address authentication */ #define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* VCPU uses generic authentication */ +#define KVM_ARM_VCPU_HAS_EL2 7 /* Support nested virtualization */ struct kvm_vcpu_init { __u32 target;
--
2.30.2
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