diff --git a/sys/arch/riscv64/conf/GENERIC b/sys/arch/riscv64/conf/GENERIC
index 9ab52540d9e..7b37947013a 100644
--- a/sys/arch/riscv64/conf/GENERIC
+++ b/sys/arch/riscv64/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.53 2025/06/28 04:21:15 kevlo Exp $
+#	$OpenBSD: GENERIC,v 1.54 2025/12/02 19:57:29 kettenis Exp $
 #
 # For further information on compiling OpenBSD kernels, see the config(8)
 # man page.
@@ -62,6 +62,9 @@ gpio*		at mpfgpio?
 mpfiic*		at fdt?
 iic*		at mpfiic?
 
+# Sophgo SoCs
+sgmsi*		at fdt?
+
 # SiFive SoCs
 sfclock*	at fdt? early 1 # PRCI
 sfcc*		at fdt? early 1	# L2 Cache Controller
diff --git a/sys/arch/riscv64/conf/RAMDISK b/sys/arch/riscv64/conf/RAMDISK
index a8d17e05099..cd0d7be6f78 100644
--- a/sys/arch/riscv64/conf/RAMDISK
+++ b/sys/arch/riscv64/conf/RAMDISK
@@ -1,4 +1,4 @@
-#	$OpenBSD: RAMDISK,v 1.46 2025/06/28 12:43:17 kevlo Exp $
+#	$OpenBSD: RAMDISK,v 1.47 2025/12/02 19:57:29 kettenis Exp $
 
 machine		riscv64
 maxusers	4
@@ -55,6 +55,9 @@ gpio*		at mpfgpio?
 mpfiic*		at fdt?
 iic*		at mpfiic?
 
+# Sophgo SoCs
+sgmsi*		at fdt?
+
 # SiFive SoCs
 sfclock*	at fdt? early 1 # PRCI
 sfcc*		at fdt? early 1	# L2 Cache Controller
diff --git a/sys/arch/riscv64/conf/files.riscv64 b/sys/arch/riscv64/conf/files.riscv64
index 179fa5edd2b..251e5d8e544 100644
--- a/sys/arch/riscv64/conf/files.riscv64
+++ b/sys/arch/riscv64/conf/files.riscv64
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.riscv64,v 1.30 2025/04/26 11:01:55 visa Exp $
+#	$OpenBSD: files.riscv64,v 1.31 2025/12/02 19:57:29 kettenis Exp $
 
 # Standard stanzas config(8) can't run without
 maxpartitions 16
@@ -120,6 +120,11 @@ device	sfuart
 attach	sfuart at fdt
 file	arch/riscv64/dev/sfuart.c		sfuart
 
+# Sophgo MSI controller
+device	sgmsi
+attach	sgmsi at fdt
+file	arch/riscv64/dev/sgmsi.c		sgmsi
+
 # StarFive clock controller
 device	stfclock
 attach	stfclock at fdt
diff --git a/sys/arch/riscv64/dev/sgmsi.c b/sys/arch/riscv64/dev/sgmsi.c
new file mode 100644
index 00000000000..1e44a867f4a
--- /dev/null
+++ b/sys/arch/riscv64/dev/sgmsi.c
@@ -0,0 +1,192 @@
+/*	$OpenBSD: sgmsi.c,v 1.1 2025/12/02 19:57:29 kettenis Exp $	*/
+/*
+ * Copyright (c) 2025 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/malloc.h>
+
+#include <machine/intr.h>
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+
+struct sgmsi_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_clr_ioh;
+
+	uint32_t		sc_msi_mask;
+	bus_addr_t		sc_msi_addr;
+	uint32_t		sc_msi_range[4];
+	struct interrupt_controller sc_msi_ic;
+};
+
+struct sgmsi_intrhand {
+	struct sgmsi_softc	*ih_sc;
+	int			(*ih_func)(void *);
+	void			*ih_arg;
+	int			ih_msi;
+	struct interrupt_controller *ih_ic;
+	void			*ih_cookie;
+};
+
+int	sgmsi_match(struct device *, void *, void *);
+void	sgmsi_attach(struct device *, struct device *, void *);
+
+const struct cfattach sgmsi_ca = {
+	sizeof (struct sgmsi_softc), sgmsi_match, sgmsi_attach
+};
+
+struct cfdriver sgmsi_cd = {
+	NULL, "sgmsi", DV_DULL
+};
+
+void	*sgmsi_intr_establish_msi(void *, uint64_t *, uint64_t *,
+	    int, struct cpu_info *, int (*)(void *), void *, char *);
+void	sgmsi_intr_disestablish_msi(void *);
+void	sgmsi_barrier(void *);
+
+int
+sgmsi_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "sophgo,sg2042-msi");
+}
+
+void
+sgmsi_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct sgmsi_softc *sc = (struct sgmsi_softc *)self;
+	struct fdt_attach_args *faa = aux;
+	int idx;
+
+	if (OF_getpropintarray(faa->fa_node, "msi-ranges", sc->sc_msi_range,
+	    sizeof(sc->sc_msi_range)) != sizeof(sc->sc_msi_range)) {
+		printf(": invalid msi-ranges property\n");
+		return;
+	}
+	sc->sc_msi_mask = (1UL << sc->sc_msi_range[3]) - 1;
+
+	idx = OF_getindex(faa->fa_node, "doorbell", "reg-names");
+	if (idx < 0 || idx >= faa->fa_nreg) {
+		printf(": no doorbell registers\n");
+		return;
+	}
+	sc->sc_msi_addr = faa->fa_reg[idx].addr;
+
+	sc->sc_iot = faa->fa_iot;
+	idx = OF_getindex(faa->fa_node, "clr", "reg-names");
+	if (idx < 0 || idx >= faa->fa_nreg) {
+		printf(": no clr registers\n");
+		return;
+	}
+	if (bus_space_map(sc->sc_iot, faa->fa_reg[idx].addr,
+	    faa->fa_reg[idx].size, 0, &sc->sc_clr_ioh)) {
+		printf(": can't map registers\n");
+		return;
+	}
+	printf("\n");
+
+	sc->sc_msi_ic.ic_node = faa->fa_node;
+	sc->sc_msi_ic.ic_cookie = sc;
+	sc->sc_msi_ic.ic_establish_msi = sgmsi_intr_establish_msi;
+	sc->sc_msi_ic.ic_disestablish = sgmsi_intr_disestablish_msi;
+	sc->sc_msi_ic.ic_barrier = sgmsi_barrier;
+	fdt_intr_register(&sc->sc_msi_ic);
+}
+
+int
+sgmsi_intr(void *arg)
+{
+	struct sgmsi_intrhand *ih = arg;
+	struct sgmsi_softc *sc = ih->ih_sc;
+
+	/* ACK the interrupt. */
+	bus_space_write_4(sc->sc_iot, sc->sc_clr_ioh, 0, (1U << ih->ih_msi));
+
+	return ih->ih_func(ih->ih_arg);
+}
+
+extern LIST_HEAD(, interrupt_controller) interrupt_controllers;
+
+void *
+sgmsi_intr_establish_msi(void *cookie, uint64_t *addr, uint64_t *data,
+    int level, struct cpu_info *ci, int (*func)(void *), void *arg, char *name)
+{
+	struct sgmsi_softc *sc = cookie;
+	struct sgmsi_intrhand *ih;
+	struct interrupt_controller *ic;
+	uint32_t cells[2];
+	int msi;
+
+	msi = ffs(sc->sc_msi_mask) - 1;
+	if (msi == -1)
+		return NULL;
+	cells[0] = sc->sc_msi_range[1] + msi;
+	cells[1] = sc->sc_msi_range[2];
+
+	/* Lookup the parent interrupt controller. */
+	LIST_FOREACH(ic, &interrupt_controllers, ic_list) {
+		if (ic->ic_phandle == sc->sc_msi_range[0])
+			break;
+	}
+	if (ic == NULL)
+		return NULL;
+
+	ih = malloc(sizeof(struct sgmsi_intrhand), M_DEVBUF, M_WAITOK);
+	ih->ih_sc = sc;
+	ih->ih_func = func;
+	ih->ih_arg = arg;
+	ih->ih_msi = msi;
+	ih->ih_ic = ic;
+	ih->ih_cookie = ic->ic_establish(ic->ic_cookie, cells, level,
+	    ci, sgmsi_intr, ih, name);
+	if (ih->ih_cookie == NULL) {
+		free(ih, M_DEVBUF, sizeof(*ih));
+		return NULL;
+	}
+	sc->sc_msi_mask &= ~(1U << ih->ih_msi);
+
+	/* ACK the interrupt. */
+	bus_space_write_4(sc->sc_iot, sc->sc_clr_ioh, 0, (1U << ih->ih_msi));
+
+	*addr = sc->sc_msi_addr;
+	*data = (1U << ih->ih_msi);
+	return ih;
+}
+
+void
+sgmsi_intr_disestablish_msi(void *cookie)
+{
+	struct sgmsi_intrhand *ih = cookie;
+
+	ih->ih_ic->ic_disestablish(ih->ih_cookie);
+	ih->ih_sc->sc_msi_mask |= (1U << ih->ih_msi);
+	free(ih, M_DEVBUF, sizeof(*ih));
+}
+
+void
+sgmsi_barrier(void *cookie)
+{
+	struct sgmsi_intrhand *ih = cookie;
+
+	ih->ih_ic->ic_barrier(ih->ih_cookie);
+}