[RFC 05/55] KVM: arm64: Add vcpu_mode_el2 primitive to support nesting

Jintack Lim
2017-01-09T06:24:01Z

From: Christoffer Dall <christoffer.dall@linaro.org>

When running a nested hypervisor we occasionally have to figure out if
the mode we are switching into is the virtual EL2 mode or a regular
EL0/1 mode.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
---
arch/arm/include/asm/kvm_emulate.h | 6 ++++++
arch/arm64/include/asm/kvm_emulate.h | 12 ++++++++++++
2 files changed, 18 insertions(+)

diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 9a8a45a..399cd75e 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -77,6 +77,12 @@ static inline bool vcpu_mode_is_32bit(const struct kvm_vcpu *vcpu)
return 1;
}

+/* We don't support nesting on arm */
+static inline bool vcpu_mode_el2(const struct kvm_vcpu *vcpu)
+{
+ return false;
+}
+
static inline unsigned long *vcpu_pc(struct kvm_vcpu *vcpu)
{
return &vcpu->arch.ctxt.gp_regs.usr_regs.ARM_pc;
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index f5ea0ba..830be2e 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -143,6 +143,18 @@ static inline bool vcpu_mode_priv(const struct kvm_vcpu *vcpu)
return mode != PSR_MODE_EL0t;
}

+static inline bool vcpu_mode_el2(const struct kvm_vcpu *vcpu)
+{
+ u32 mode;
+
+ if (vcpu_mode_is_32bit(vcpu))
+ return false;
+
+ mode = *vcpu_cpsr(vcpu) & PSR_MODE_MASK;
+
+ return mode == PSR_MODE_EL2h || mode == PSR_MODE_EL2t;
+}
+
static inline u32 kvm_vcpu_get_hsr(const struct kvm_vcpu *vcpu)
{
return vcpu->arch.fault.esr_el2;
--
1.9.1