[PATCH v6 06/64] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state

Marc Zyngier
2022-01-28T12:22:24Z

From: Christoffer Dall <christoffer.dall@arm.com>

When running a nested hypervisor we commonly have to figure out if
the VCPU mode is running in the context of a guest hypervisor or guest
guest, or just a normal guest.

Add convenient primitives for this.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_emulate.h | 53 ++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index d62405ce3e6d..ea9a130c4b6a 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -178,6 +178,59 @@ static __always_inline void vcpu_set_reg(struct kvm_vcpu *vcpu, u8 reg_num,
vcpu_gp_regs(vcpu)->regs[reg_num] = val;
}

+static inline bool vcpu_is_el2_ctxt(const struct kvm_cpu_context *ctxt)
+{
+ switch (ctxt->regs.pstate & (PSR_MODE32_BIT | PSR_MODE_MASK)) {
+ case PSR_MODE_EL2h:
+ case PSR_MODE_EL2t:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static inline bool vcpu_is_el2(const struct kvm_vcpu *vcpu)
+{
+ return vcpu_is_el2_ctxt(&vcpu->arch.ctxt);
+}
+
+static inline bool __vcpu_el2_e2h_is_set(const struct kvm_cpu_context *ctxt)
+{
+ return ctxt_sys_reg(ctxt, HCR_EL2) & HCR_E2H;
+}
+
+static inline bool vcpu_el2_e2h_is_set(const struct kvm_vcpu *vcpu)
+{
+ return __vcpu_el2_e2h_is_set(&vcpu->arch.ctxt);
+}
+
+static inline bool __vcpu_el2_tge_is_set(const struct kvm_cpu_context *ctxt)
+{
+ return ctxt_sys_reg(ctxt, HCR_EL2) & HCR_TGE;
+}
+
+static inline bool vcpu_el2_tge_is_set(const struct kvm_vcpu *vcpu)
+{
+ return __vcpu_el2_tge_is_set(&vcpu->arch.ctxt);
+}
+
+static inline bool __is_hyp_ctxt(const struct kvm_cpu_context *ctxt)
+{
+ /*
+ * We are in a hypervisor context if the vcpu mode is EL2 or
+ * E2H and TGE bits are set. The latter means we are in the user space
+ * of the VHE kernel. ARMv8.1 ARM describes this as 'InHost'
+ */
+ return vcpu_is_el2_ctxt(ctxt) ||
+ (__vcpu_el2_e2h_is_set(ctxt) && __vcpu_el2_tge_is_set(ctxt)) ||
+ WARN_ON(__vcpu_el2_tge_is_set(ctxt));
+}
+
+static inline bool is_hyp_ctxt(const struct kvm_vcpu *vcpu)
+{
+ return __is_hyp_ctxt(&vcpu->arch.ctxt);
+}
+
/*
* The layout of SPSR for an AArch32 state is different when observed from an
* AArch64 SPSR_ELx or an AArch32 SPSR_*. This function generates the AArch32