[PATCH v2 07/15] KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context

Oliver Upton
2024-06-13T20:18:44Z

When running a guest hypervisor, ZCR_EL2 is an alias for the counterpart
EL1 state.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/fpsimd.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 1807d3a79a8a..53168bbea8a7 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -173,7 +173,16 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)

if (guest_owns_fp_regs()) {
if (vcpu_has_sve(vcpu)) {
- __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
+ u64 zcr = read_sysreg_el1(SYS_ZCR);
+
+ /*
+ * If the vCPU is in the hyp context then ZCR_EL1 is
+ * loaded with its vEL2 counterpart.
+ */
+ if (is_hyp_ctxt(vcpu))
+ __vcpu_sys_reg(vcpu, ZCR_EL2) = zcr;
+ else
+ __vcpu_sys_reg(vcpu, ZCR_EL1) = zcr;

/*
* Restore the VL that was saved when bound to the CPU,
--
2.45.2.627.g7a2c4fd464-goog