Re: [PATCH v5 2/5] KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation

Hi David,

On Thu, Sep 26, 2024 at 07:37:57PM +0100, David Woodhouse wrote:

@@ -392,6 +403,32 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor) break; } break;

• case PSCI_1_3_FN_SYSTEM_OFF2:

• kvm_psci_narrow_to_32bit(vcpu);
  

• fallthrough;
  

• case PSCI_1_3_FN64_SYSTEM_OFF2:

• if (minor < 3)
  

• 	break;
  

• arg = smccc_get_arg1(vcpu);
  

• if (arg != PSCI_1_3_HIBERNATE_TYPE_OFF) {
  

• 	val = PSCI_RET_INVALID_PARAMS;
  

• 	break;
  

• }
  

This is missing a check that arg2 must be zero.

• kvm_psci_system_off2(vcpu);
  

• /*
  

•  * We shouldn't be going back to guest VCPU after
  

•  * receiving SYSTEM_OFF2 request.
  

•  *
  

•  * If user space accidentally/deliberately resumes
  

•  * guest VCPU after SYSTEM_OFF2 request then guest
  

•  * VCPU should see internal failure from PSCI return
  

•  * value. To achieve this, we preload r0 (or x0) with
  

•  * PSCI return value INTERNAL_FAILURE.
  

•  */
  

• val = PSCI_RET_INTERNAL_FAILURE;
  

• ret = 0;
  

• break;
  

  default: return kvm_psci_0_2_call(vcpu); }

-- 2.44.0