KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state

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>
Link: https://lore.kernel.org/r/20230209175820.1939006-8-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 193583df2d9c45761ded5a28a750e7d539d96945..e5d826dc0b634bcadc24ed6d2243036222837730 100644 (file)
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -183,6 +183,62 @@ 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'
+        *
+        * Note that the HCR_EL2.{E2H,TGE}={0,1} isn't really handled in the
+        * rest of the KVM code, and will result in a misbehaving guest.
+        */
+       return vcpu_is_el2_ctxt(ctxt) ||
+               (__vcpu_el2_e2h_is_set(ctxt) && __vcpu_el2_tge_is_set(ctxt)) ||
+               __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