[PATCH 2/2] KVM: SVM: Provide helpers to set the error code

Melody Wang
2024-12-06T22:13:55Z

Provide helpers to set the error code when converting VMGEXIT SW_EXITINFO1 and
SW_EXITINFO2 codes from plain numbers to proper defines. Add comments for
better code readability.

No functionality changed.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
arch/x86/kvm/svm/sev.c | 39 +++++++++++++++++++++------------------
arch/x86/kvm/svm/svm.c | 6 +-----
arch/x86/kvm/svm/svm.h | 24 ++++++++++++++++++++++++
3 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e7db7a5703b7..409f77a6151e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3433,8 +3433,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
dump_ghcb(svm);
}

- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_MALFORMED_INPUT);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, reason);
+ svm_vmgexit_bad_input(svm, reason);

/* Resume the guest to "return" the error code. */
return 1;
@@ -3577,8 +3576,7 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
return 0;

e_scratch:
- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_MALFORMED_INPUT);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_SCRATCH_AREA);
+ svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_SCRATCH_AREA);

return 1;
}
@@ -3671,7 +3669,11 @@ static void snp_complete_psc(struct vcpu_svm *svm, u64 psc_ret)
svm->sev_es.psc_inflight = 0;
svm->sev_es.psc_idx = 0;
svm->sev_es.psc_2m = false;
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, psc_ret);
+ /*
+ * psc_ret contains 0 if all entries have been processed successfully
+ * or a reason code identifying why the request has not completed.
+ */
+ svm_vmgexit_set_return_code(svm, 0, psc_ret);
}

static void __snp_complete_one_psc(struct vcpu_svm *svm)
@@ -4067,8 +4069,12 @@ static int snp_handle_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_
ret = -EIO;
goto out_unlock;
}
-
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(0, fw_err));
+ /*
+ * SNP_GUEST_ERR(0, fw_err): Upper 32-bits (63:32) will contain the
+ * return code from the hypervisor. Lower 32-bits (31:0) will contain
+ * the return code from the firmware call (0 = success)
+ */
+ svm_vmgexit_set_return_code(svm, 0, SNP_GUEST_ERR(0, fw_err));

ret = 1; /* resume guest */

@@ -4124,8 +4130,7 @@ static int snp_handle_ext_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t r
return snp_handle_guest_req(svm, req_gpa, resp_gpa);

request_invalid:
- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_MALFORMED_INPUT);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+ svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_INPUT);
return 1; /* resume guest */
}

@@ -4317,8 +4322,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
if (ret)
return ret;

- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_SUCCESS);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, 0);
+ svm_vmgexit_success(svm, 0);

exit_code = kvm_ghcb_get_sw_exit_code(control);
switch (exit_code) {
@@ -4362,20 +4366,20 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
break;
case 1:
/* Get AP jump table address */
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, sev->ap_jump_table);
+ svm_vmgexit_set_return_code(svm, 0, sev->ap_jump_table);
break;
default:
pr_err("svm: vmgexit: unsupported AP jump table request - exit_info_1=%#llx\n",
control->exit_info_1);
- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_MALFORMED_INPUT);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+ svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_INPUT);
}

ret = 1;
break;
}
case SVM_VMGEXIT_HV_FEATURES:
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_HV_FT_SUPPORTED);
+ /* Get hypervisor supported features */
+ svm_vmgexit_success(svm, GHCB_HV_FT_SUPPORTED);

ret = 1;
break;
@@ -4397,8 +4401,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
case SVM_VMGEXIT_AP_CREATION:
ret = sev_snp_ap_creation(svm);
if (ret) {
- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_MALFORMED_INPUT);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+ svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_INPUT);
}

ret = 1;
@@ -4635,7 +4638,7 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
* Return from an AP Reset Hold VMGEXIT, where the guest will
* set the CS and RIP. Set SW_EXIT_INFO_2 to a non-zero value.
*/
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, 1);
+ svm_vmgexit_success(svm, 1);
break;
case AP_RESET_HOLD_MSR_PROTO:
/*
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58bce5f1ab0c..104e13d59c8a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2977,11 +2977,7 @@ static int svm_complete_emulated_msr(struct kvm_vcpu *vcpu, int err)
if (!err || !sev_es_guest(vcpu->kvm) || WARN_ON_ONCE(!svm->sev_es.ghcb))
return kvm_complete_insn_gp(vcpu, err);

- ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, GHCB_HV_RESP_ISSUE_EXCEPTION);
- ghcb_set_sw_exit_info_2(svm->sev_es.ghcb,
- X86_TRAP_GP |
- SVM_EVTINJ_TYPE_EXEPT |
- SVM_EVTINJ_VALID);
+ svm_vmgexit_inject_exception(svm, X86_TRAP_GP);
return 1;
}

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 43fa6a16eb19..baff8237c5c9 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -588,6 +588,30 @@ static inline bool is_vnmi_enabled(struct vcpu_svm *svm)
return false;
}

+static inline void svm_vmgexit_set_return_code(struct vcpu_svm *svm,
+ u64 response, u64 data)
+{
+ ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, response);
+ ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, data);
+}
+
+static inline void svm_vmgexit_inject_exception(struct vcpu_svm *svm, u8 vector)
+{
+ u64 data = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_EXEPT | vector;
+
+ svm_vmgexit_set_return_code(svm, GHCB_HV_RESP_ISSUE_EXCEPTION, data);
+}
+
+static inline void svm_vmgexit_bad_input(struct vcpu_svm *svm, u64 suberror)
+{
+ svm_vmgexit_set_return_code(svm, GHCB_HV_RESP_MALFORMED_INPUT, suberror);
+}
+
+static inline void svm_vmgexit_success(struct vcpu_svm *svm, u64 data)
+{
+ svm_vmgexit_set_return_code(svm, GHCB_HV_RESP_SUCCESS, data);
+}
+
/* svm.c */
#define MSR_INVALID 0xffffffffU

--
2.34.1