KVM: SVM: Provide helpers to set the error code

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>
Link: https://lore.kernel.org/r/20250225213937.2471419-3-huibo.wang@amd.com
[sean: tweak comments, fix formatting goofs]
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 818e66404fa01ccf2484cf697e1f822bf6a92122..5c236e4444e8dbe88eb6c92a5b242f4c9d11943f 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3410,8 +3410,7 @@ vmgexit_err:
                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;
@@ -3554,8 +3553,7 @@ 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;
 }
@@ -3655,7 +3653,14 @@ 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 requests always get a "no action" response in SW_EXITINFO1, with
+        * a PSC-specific return code in SW_EXITINFO2 that provides the "real"
+        * return code.  E.g. if the PSC request was interrupted, the need to
+        * retry is communicated via SW_EXITINFO2, not SW_EXITINFO1.
+        */
+       svm_vmgexit_no_action(svm, psc_ret);
 }
 
 static void __snp_complete_one_psc(struct vcpu_svm *svm)
@@ -4058,7 +4063,8 @@ static int snp_handle_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_
                goto out_unlock;
        }
 
-       ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(0, fw_err));
+       /* No action is requested *from KVM* if there was a firmware error. */
+       svm_vmgexit_no_action(svm, SNP_GUEST_ERR(0, fw_err));
 
        ret = 1; /* resume guest */
 
@@ -4114,8 +4120,7 @@ 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 */
 }
 
@@ -4307,8 +4312,7 @@ 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_NO_ACTION);
-       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) {
@@ -4352,21 +4356,19 @@ 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_success(svm, 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);
-
+               svm_vmgexit_success(svm, GHCB_HV_FT_SUPPORTED);
                ret = 1;
                break;
        case SVM_VMGEXIT_TERM_REQUEST:
@@ -4387,8 +4389,7 @@ 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;
@@ -4624,7 +4625,7 @@ 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 a115f219809c45ab6d026b86870b934d5ea1b46e..690909a93c6030a9663b7b15c060f26b1b5dabc9 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2973,11 +2973,7 @@ 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 5b159f0170552fa243d4fc24dbc584e31c3cb8f2..faa5c0dab0ea330cf22c7d167289ed1088b0fd2d 100644 (file)
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -579,6 +579,35 @@ 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_NO_ACTION, data);
+}
+
+static inline void svm_vmgexit_no_action(struct vcpu_svm *svm, u64 data)
+{
+       svm_vmgexit_set_return_code(svm, GHCB_HV_RESP_NO_ACTION, data);
+}
+
 /* svm.c */
 #define MSR_INVALID                            0xffffffffU