diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 85c7abc51af5..4a900cdbc62e 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5986,16 +5986,16 @@ should put the acknowledged interrupt vector into the 'epr' field.
   #define KVM_SYSTEM_EVENT_RESET          2
   #define KVM_SYSTEM_EVENT_CRASH          3
 			__u32 type;
-			__u64 flags;
+                        __u32 ndata;
+                        __u64 data[16];
 		} system_event;
 
 If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
 a system-level event using some architecture specific mechanism (hypercall
 or some special instruction). In case of ARM64, this is triggered using
-HVC instruction based PSCI call from the vcpu. The 'type' field describes
-the system-level event type. The 'flags' field describes architecture
-specific flags for the system-level event.
+HVC instruction based PSCI call from the vcpu.
 
+The 'type' field describes the system-level event type.
 Valid values for 'type' are:
 
  - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the
@@ -6010,10 +6010,20 @@ Valid values for 'type' are:
    to ignore the request, or to gather VM memory core dump and/or
    reset/shutdown of the VM.
 
-Valid flags are:
+If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain
+architecture specific information for the system-level event.  Only
+the first `ndata` items (possibly zero) of the data array are valid.
 
- - KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (arm64 only) -- the guest issued
-   a SYSTEM_RESET2 call according to v1.1 of the PSCI specification.
+ - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if
+   the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI
+   specification.
+
+ - for RISC-V, data[0] is set to the value of the second argument of the
+   ``sbi_system_reset`` call.
+
+Previous versions of Linux defined a `flags` member in this struct.  The
+field is now aliased to `data[0]`.  Userspace can assume that it is only
+written if ndata is greater than 0.
 
 ::
 
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index baac2b405f23..708d80e8e60d 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -181,7 +181,8 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
 
 	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
 	vcpu->run->system_event.type = type;
-	vcpu->run->system_event.flags = flags;
+	vcpu->run->system_event.ndata = 1;
+	vcpu->run->system_event.data[0] = flags;
 	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 }
 
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index a09ecb97b890..d45e7da3f0d3 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -83,7 +83,7 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
 				     struct kvm_run *run,
-				     u32 type, u64 flags)
+				     u32 type, u64 reason)
 {
 	unsigned long i;
 	struct kvm_vcpu *tmp;
@@ -94,7 +94,8 @@ void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
 
 	memset(&run->system_event, 0, sizeof(run->system_event));
 	run->system_event.type = type;
-	run->system_event.flags = flags;
+	run->system_event.ndata = 1;
+	run->system_event.data[0] = reason;
 	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 43174a8d9497..07d789b1d366 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10015,12 +10015,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) {
 			vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 			vcpu->run->system_event.type = KVM_SYSTEM_EVENT_CRASH;
+			vcpu->run->system_event.ndata = 0;
 			r = 0;
 			goto out;
 		}
 		if (kvm_check_request(KVM_REQ_HV_RESET, vcpu)) {
 			vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 			vcpu->run->system_event.type = KVM_SYSTEM_EVENT_RESET;
+			vcpu->run->system_event.ndata = 0;
 			r = 0;
 			goto out;
 		}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 91a6fe4e02c0..6a184d260c7f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -445,7 +445,13 @@ struct kvm_run {
 #define KVM_SYSTEM_EVENT_RESET          2
 #define KVM_SYSTEM_EVENT_CRASH          3
 			__u32 type;
-			__u64 flags;
+			__u32 ndata;
+			union {
+#ifndef __KERNEL__
+				__u64 flags;
+#endif
+				__u64 data[16];
+			};
 		} system_event;
 		/* KVM_EXIT_S390_STSI */
 		struct {
@@ -1144,6 +1150,8 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_S390_MEM_OP_EXTENSION 211
 #define KVM_CAP_PMU_CAPABILITY 212
 #define KVM_CAP_DISABLE_QUIRKS2 213
+/* #define KVM_CAP_VM_TSC_CONTROL 214 */
+#define KVM_CAP_SYSTEM_EVENT_DATA 215
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index dfb7dabdbc63..ac57fc2c935f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4333,6 +4333,7 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 		return 0;
 #endif
 	case KVM_CAP_BINARY_STATS_FD:
+	case KVM_CAP_SYSTEM_EVENT_DATA:
 		return 1;
 	default:
 		break;