KVM: arm64: Really propagate PSCI SYSTEM_RESET2 arguments to userspace

Commit d43583b890e7 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest") hooked up the SYSTEM_RESET2 PSCI call for guests but failed to preserve its arguments for userspace, instead overwriting them with zeroes via smccc_set_retval(). As Linux only passes zeroes for these arguments, this appeared to be working for Linux guests. Oh well.

Don't call smccc_set_retval() for a SYSTEM_RESET2 heading to userspace and instead set X0 (and only X0) explicitly to PSCI_RET_INTERNAL_FAILURE just in case the vCPU re-enters the guest.

---
 arch/arm64/kvm/psci.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

index ecb4b74cb12a..b0c920717632 100644
@@ -367,14 +367,14 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 		if (minor >= 1) {
 			arg = smccc_get_arg1(vcpu);
 
-			if (arg > PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET &&
-			    arg < PSCI_1_1_RESET_TYPE_VENDOR_START) {
-				val = PSCI_RET_INVALID_PARAMS;
-			} else {
+			if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET ||
+			    arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
 				kvm_psci_system_reset2(vcpu);
-				val = PSCI_RET_INTERNAL_FAILURE;
-				ret = 0;
+				vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
+				return 0;
 			}
+
+			val = PSCI_RET_INVALID_PARAMS;
 			break;
 		};
 		fallthrough;

2.35.1.616.g0bdcbb4464-goog

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Applied to next, thanks!

[1/1] KVM: arm64: Really propagate PSCI SYSTEM_RESET2 arguments to userspace

      commit: 9d3e7b7c82fd9d40240867ef4c45388cd05031f3

Cheers,

	M.

Without deviation from the norm, progress is not possible.


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