[PATCH v2 02/15] KVM: arm64: nv: Forward SVE traps to guest hypervisor

Oliver Upton
2024-06-13T20:18:35Z

Similar to FPSIMD traps, don't load SVE state if the guest hypervisor
has SVE traps enabled and forward the trap instead. Note that ZCR_EL2
will require some special handling, as it takes a sysreg trap to EL2
when HCR_EL2.NV = 1.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/include/asm/kvm_emulate.h | 4 ++++
arch/arm64/kvm/handle_exit.c | 3 +++
arch/arm64/kvm/hyp/include/hyp/switch.h | 2 ++
3 files changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index c3c5a5999ed7..cc5c93b46e6f 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -641,5 +641,9 @@ static inline bool guest_hyp_fpsimd_traps_enabled(const struct kvm_vcpu *vcpu)
return __guest_hyp_cptr_xen_trap_enabled(vcpu, FPEN);
}

+static inline bool guest_hyp_sve_traps_enabled(const struct kvm_vcpu *vcpu)
+{
+ return __guest_hyp_cptr_xen_trap_enabled(vcpu, ZEN);
+}

#endif /* __ARM64_KVM_EMULATE_H__ */
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 59fe9b10a87a..e4f74699f360 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -217,6 +217,9 @@ static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu)
*/
static int handle_sve(struct kvm_vcpu *vcpu)
{
+ if (guest_hyp_sve_traps_enabled(vcpu))
+ return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
+
kvm_inject_undefined(vcpu);
return 1;
}
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index b302d32f8326..428ee15dd6ae 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -348,6 +348,8 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
case ESR_ELx_EC_SVE:
if (!sve_guest)
return false;
+ if (guest_hyp_sve_traps_enabled(vcpu))
+ return false;
break;
default:
return false;
--
2.45.2.627.g7a2c4fd464-goog