i386/tdx: handle TDVMCALL_SETUP_EVENT_NOTIFY_INTERRUPT

Record the interrupt vector and the apic id of the vcpu that calls
TDVMCALL_SETUP_EVENT_NOTIFY_INTERRUPT.

Inject the interrupt to TD guest to notify the completion of <GetQuote>
when notify interrupt vector is valid.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250703024021.3559286-5-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/kvm/kvm.c

@@ -6182,6 +6182,9 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
         case TDVMCALL_GET_TD_VM_CALL_INFO:
             tdx_handle_get_tdvmcall_info(cpu, run);
             break;
+        case TDVMCALL_SETUP_EVENT_NOTIFY_INTERRUPT:
+            tdx_handle_setup_event_notify_interrupt(cpu, run);
+            break;
         }
         ret = 0;
         break;

target/i386/kvm/tdx-stub.c

@@ -26,3 +26,7 @@ void tdx_handle_get_quote(X86CPU *cpu, struct kvm_run *run)
 void tdx_handle_get_tdvmcall_info(X86CPU *cpu, struct kvm_run *run)
 {
 }
+
+void tdx_handle_setup_event_notify_interrupt(X86CPU *cpu, struct kvm_run *run)
+{
+}

target/i386/kvm/tdx.c

@@ -28,10 +28,13 @@
 #include "cpu.h"
 #include "cpu-internal.h"
 #include "host-cpu.h"
+#include "hw/i386/apic_internal.h"
+#include "hw/i386/apic-msidef.h"
 #include "hw/i386/e820_memory_layout.h"
 #include "hw/i386/tdvf.h"
 #include "hw/i386/x86.h"
 #include "hw/i386/tdvf-hob.h"
+#include "hw/pci/msi.h"
 #include "kvm_i386.h"
 #include "tdx.h"
 #include "tdx-quote-generator.h"
@@ -1123,6 +1126,28 @@ int tdx_parse_tdvf(void *flash_ptr, int size)
     return tdvf_parse_metadata(&tdx_guest->tdvf, flash_ptr, size);
 }
 
+static void tdx_inject_interrupt(uint32_t apicid, uint32_t vector)
+{
+    int ret;
+
+    if (vector < 32 || vector > 255) {
+        return;
+    }
+
+    MSIMessage msg = {
+        .address = ((apicid & 0xff) << MSI_ADDR_DEST_ID_SHIFT) |
+                   (((uint64_t)apicid & 0xffffff00) << 32),
+        .data = vector | (APIC_DM_FIXED << MSI_DATA_DELIVERY_MODE_SHIFT),
+    };
+
+    ret = kvm_irqchip_send_msi(kvm_state, msg);
+    if (ret < 0) {
+        /* In this case, no better way to tell it to guest. Log it. */
+        error_report("TDX: injection interrupt %d failed, interrupt lost (%s).",
+                     vector, strerror(-ret));
+    }
+}
+
 static void tdx_get_quote_completion(TdxGenerateQuoteTask *task)
 {
     TdxGuest *tdx = task->opaque;
@@ -1154,6 +1179,9 @@ static void tdx_get_quote_completion(TdxGenerateQuoteTask *task)
         error_report("TDX: get-quote: failed to update GetQuote header.");
     }
 
+    tdx_inject_interrupt(tdx_guest->event_notify_apicid,
+                         tdx_guest->event_notify_vector);
+
     g_free(task->send_data);
     g_free(task->receive_buf);
     g_free(task);
@@ -1256,7 +1284,7 @@ out_free:
     g_free(task);
 }
 
-#define SUPPORTED_TDVMCALLINFO_1_R11    (0)
+#define SUPPORTED_TDVMCALLINFO_1_R11    (TDG_VP_VMCALL_SUBFUNC_SET_EVENT_NOTIFY_INTERRUPT)
 #define SUPPORTED_TDVMCALLINFO_1_R12    (0)
 
 void tdx_handle_get_tdvmcall_info(X86CPU *cpu, struct kvm_run *run)
@@ -1277,6 +1305,21 @@ void tdx_handle_get_tdvmcall_info(X86CPU *cpu, struct kvm_run *run)
     run->tdx.get_tdvmcall_info.ret = TDG_VP_VMCALL_SUCCESS;
 }
 
+void tdx_handle_setup_event_notify_interrupt(X86CPU *cpu, struct kvm_run *run)
+{
+    uint64_t vector = run->tdx.setup_event_notify.vector;
+
+    if (vector >= 32 && vector < 256) {
+        qemu_mutex_lock(&tdx_guest->lock);
+        tdx_guest->event_notify_vector = vector;
+        tdx_guest->event_notify_apicid = cpu->apic_id;
+        qemu_mutex_unlock(&tdx_guest->lock);
+        run->tdx.setup_event_notify.ret = TDG_VP_VMCALL_SUCCESS;
+    } else {
+        run->tdx.setup_event_notify.ret = TDG_VP_VMCALL_INVALID_OPERAND;
+    }
+}
+
 static void tdx_panicked_on_fatal_error(X86CPU *cpu, uint64_t error_code,
                                         char *message, uint64_t gpa)
 {
@@ -1477,6 +1520,9 @@ static void tdx_guest_init(Object *obj)
                             NULL, NULL);
 
     qemu_mutex_init(&tdx->lock);
+
+    tdx->event_notify_vector = -1;
+    tdx->event_notify_apicid = -1;
 }
 
 static void tdx_guest_finalize(Object *obj)

target/i386/kvm/tdx.h

@@ -25,6 +25,7 @@ typedef struct TdxGuestClass {
 
 #define TDVMCALL_GET_TD_VM_CALL_INFO    0x10000
 #define TDVMCALL_GET_QUOTE		 0x10002
+#define TDVMCALL_SETUP_EVENT_NOTIFY_INTERRUPT   0x10004
 
 #define TDG_VP_VMCALL_SUCCESS           0x0000000000000000ULL
 #define TDG_VP_VMCALL_RETRY             0x0000000000000001ULL
@@ -32,6 +33,8 @@ typedef struct TdxGuestClass {
 #define TDG_VP_VMCALL_GPA_INUSE         0x8000000000000001ULL
 #define TDG_VP_VMCALL_ALIGN_ERROR       0x8000000000000002ULL
 
+#define TDG_VP_VMCALL_SUBFUNC_SET_EVENT_NOTIFY_INTERRUPT BIT_ULL(1)
+
 enum TdxRamType {
     TDX_RAM_UNACCEPTED,
     TDX_RAM_ADDED,
@@ -64,6 +67,9 @@ typedef struct TdxGuest {
     /* GetQuote */
     SocketAddress *qg_sock_addr;
     int num;
+
+    uint32_t event_notify_vector;
+    uint32_t event_notify_apicid;
 } TdxGuest;
 
 #ifdef CONFIG_TDX
@@ -78,5 +84,6 @@ int tdx_parse_tdvf(void *flash_ptr, int size);
 int tdx_handle_report_fatal_error(X86CPU *cpu, struct kvm_run *run);
 void tdx_handle_get_quote(X86CPU *cpu, struct kvm_run *run);
 void tdx_handle_get_tdvmcall_info(X86CPU *cpu, struct kvm_run *run);
+void tdx_handle_setup_event_notify_interrupt(X86CPU *cpu, struct kvm_run *run);
 
 #endif /* QEMU_I386_TDX_H */