io_uring: add support for IORING_{,UN}REGISTER_PBUF_RING opcodes

Introduced by Linux commit v5.19-rc1~251^2~10.

* src/xlat/uring_register_opcodes.in (IORING_REGISTER_PBUF_RING,
IORING_UNREGISTER_PBUF_RING): New constants.
* src/io_uring.c (print_io_uring_buf_reg): New function.
(SYS_FUNC(io_uring_register)) <case IORING_REGISTER_PBUF_RING,
case IORING_UNREGISTER_PBUF_RING>: Call print_io_uring_buf_reg
for decoding.
* tests/io_uring_register.c: Update expected output, add checks.

2 files changed, 98 insertions, 0 deletions

diff --git a/src/io_uring.c b/src/io_uring.c
index e59ccbe3c..1f3c6bb5d 100644
--- a/src/io_uring.c
+++ b/src/io_uring.c
@@ -560,6 +560,39 @@ print_io_uring_ringfds_unregister(struct tcb *tcp, const kernel_ulong_t arg,
 		    tfetch_mem, print_ringfd_unregister_array_member, NULL);
 }
 
+static void
+print_io_uring_buf_reg(struct tcb *tcp, const kernel_ulong_t addr)
+{
+	struct io_uring_buf_reg arg;
+	CHECK_TYPE_SIZE(arg, 40);
+	CHECK_TYPE_SIZE(arg.pad, sizeof(uint16_t));
+	CHECK_TYPE_SIZE(arg.resv, sizeof(uint64_t) * 3);
+
+	if (umove_or_printaddr(tcp, addr, &arg))
+		return;
+
+	tprint_struct_begin();
+	PRINT_FIELD_ADDR64(arg, ring_addr);
+
+	tprint_struct_next();
+	PRINT_FIELD_U(arg, ring_entries);
+
+	tprint_struct_next();
+	PRINT_FIELD_U(arg, bgid);
+
+	if (arg.pad) {
+		tprint_struct_next();
+		PRINT_FIELD_X(arg, pad);
+	}
+
+	if (!IS_ARRAY_ZERO(arg.resv)) {
+		tprint_struct_next();
+		PRINT_FIELD_ARRAY(arg, resv, tcp, print_xint_array_member);
+	}
+
+	tprint_struct_end();
+}
+
 SYS_FUNC(io_uring_register)
 {
 	const int fd = tcp->u_arg[0];
@@ -622,6 +655,10 @@ SYS_FUNC(io_uring_register)
 	case IORING_UNREGISTER_RING_FDS:
 		print_io_uring_ringfds_unregister(tcp, arg, nargs);
 		break;
+	case IORING_REGISTER_PBUF_RING:
+	case IORING_UNREGISTER_PBUF_RING:
+		print_io_uring_buf_reg(tcp, arg);
+		break;
 	case IORING_UNREGISTER_BUFFERS:
 	case IORING_UNREGISTER_FILES:
 	case IORING_UNREGISTER_EVENTFD:
diff --git a/tests/io_uring_register.c b/tests/io_uring_register.c
index b87b3c9bd..3b0d4c16a 100644
--- a/tests/io_uring_register.c
+++ b/tests/io_uring_register.c
@@ -1067,6 +1067,67 @@ main(void)
 		}
 	}
 
+
+	/* IORING_REGISTER_PBUF_RING, IORING_UNREGISTER_PBUF_RING */
+	static const struct {
+		unsigned int op;
+		const char *str;
+	} buf_reg_ops[] = {
+		{ 22, "IORING_REGISTER_PBUF_RING" },
+		{ 23, "IORING_UNREGISTER_PBUF_RING" },
+	};
+	TAIL_ALLOC_OBJECT_VAR_PTR(struct io_uring_buf_reg, buf_reg);
+
+	for (size_t i = 0; i < ARRAY_SIZE(buf_reg_ops); i++) {
+		sys_io_uring_register(fd_null, buf_reg_ops[i].op, 0,
+				      0xdeadbeef);
+		printf("io_uring_register(%u<%s>, " XLAT_FMT ", NULL, %u)"
+		       " = %s\n",
+		       fd_null, path_null,
+		       XLAT_SEL(buf_reg_ops[i].op, buf_reg_ops[i].str),
+		       0xdeadbeef, errstr);
+
+		sys_io_uring_register(fd_null, buf_reg_ops[i].op,
+				      buf_reg + 1, 0);
+		printf("io_uring_register(%u<%s>, " XLAT_FMT ", %p, 0) = %s\n",
+		       fd_null, path_null,
+		       XLAT_SEL(buf_reg_ops[i].op, buf_reg_ops[i].str),
+		       buf_reg + 1, errstr);
+
+		for (size_t j = 0; j < 256; j++) {
+			memset(buf_reg, 0, sizeof(*buf_reg));
+			buf_reg->ring_addr = j & 2 ? (uintptr_t) buf_reg : 0;
+			buf_reg->ring_entries = j & 4 ? 3141592653 : 0;
+			buf_reg->bgid = j & 8 ? 42069 : 0;
+			buf_reg->pad = j & 16 ? 31337 : 0;
+			buf_reg->resv[0] = j &  32 ? 0xbadc0deddeadfaceULL : 0;
+			buf_reg->resv[1] = j &  64 ? 0xdecaffedbeefdeadULL : 0;
+			buf_reg->resv[2] = j & 128 ? 0xbadc0dedfacefeedULL : 0;
+
+			sys_io_uring_register(fd_null, buf_reg_ops[i].op,
+					      buf_reg, 0x42);
+			printf("io_uring_register(%u<%s>, " XLAT_FMT
+			       ", {ring_addr=",
+			       fd_null, path_null,
+			       XLAT_SEL(buf_reg_ops[i].op, buf_reg_ops[i].str));
+			if (j & 2)
+				printf("%p", buf_reg);
+			else
+				printf("NULL");
+			printf(", ring_entries=%s, bgid=%s%s",
+			       j & 4 ? "3141592653" : "0",
+			       j & 8 ? "42069" : "0",
+			       j & 16 ? ", pad=0x7a69" : "");
+			if (j & 0xe0) {
+				printf(", resv=[%s, %s, %s]",
+				       j &  32 ? "0xbadc0deddeadface" : "0",
+				       j &  64 ? "0xdecaffedbeefdead" : "0",
+				       j & 128 ? "0xbadc0dedfacefeed" : "0");
+			}
+			printf("}, 66) = %s\n", errstr);
+		}
+	}
+
 	puts("+++ exited with 0 +++");
 	return 0;
 }