hw/cxl/device: Implement basic mailbox (8.2.8.4)

This is the beginning of implementing mailbox support for CXL 2.0
devices. The implementation recognizes when the doorbell is rung,
handles the command/payload, clears the doorbell while returning error
codes and data.

Generally the mailbox mechanism is designed to permit communication
between the host OS and the firmware running on the device. For our
purposes, we emulate both the firmware, implemented primarily in
cxl-mailbox-utils.c, and the hardware.

No commands are implemented yet.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-7-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
new file mode 100644
index 0000000000..2557f41f61
--- /dev/null
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -0,0 +1,164 @@
+/*
+ * CXL Utility library for mailbox interface
+ *
+ * Copyright(C) 2020 Intel Corporation.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See the
+ * COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/cxl/cxl.h"
+#include "hw/pci/pci.h"
+#include "qemu/log.h"
+#include "qemu/uuid.h"
+
+/*
+ * How to add a new command, example. The command set FOO, with cmd BAR.
+ *  1. Add the command set and cmd to the enum.
+ *     FOO    = 0x7f,
+ *          #define BAR 0
+ *  2. Implement the handler
+ *    static ret_code cmd_foo_bar(struct cxl_cmd *cmd,
+ *                                  CXLDeviceState *cxl_dstate, uint16_t *len)
+ *  3. Add the command to the cxl_cmd_set[][]
+ *    [FOO][BAR] = { "FOO_BAR", cmd_foo_bar, x, y },
+ *  4. Implement your handler
+ *     define_mailbox_handler(FOO_BAR) { ... return CXL_MBOX_SUCCESS; }
+ *
+ *
+ *  Writing the handler:
+ *    The handler will provide the &struct cxl_cmd, the &CXLDeviceState, and the
+ *    in/out length of the payload. The handler is responsible for consuming the
+ *    payload from cmd->payload and operating upon it as necessary. It must then
+ *    fill the output data into cmd->payload (overwriting what was there),
+ *    setting the length, and returning a valid return code.
+ *
+ *  XXX: The handler need not worry about endianess. The payload is read out of
+ *  a register interface that already deals with it.
+ */
+
+/* 8.2.8.4.5.1 Command Return Codes */
+typedef enum {
+    CXL_MBOX_SUCCESS = 0x0,
+    CXL_MBOX_BG_STARTED = 0x1,
+    CXL_MBOX_INVALID_INPUT = 0x2,
+    CXL_MBOX_UNSUPPORTED = 0x3,
+    CXL_MBOX_INTERNAL_ERROR = 0x4,
+    CXL_MBOX_RETRY_REQUIRED = 0x5,
+    CXL_MBOX_BUSY = 0x6,
+    CXL_MBOX_MEDIA_DISABLED = 0x7,
+    CXL_MBOX_FW_XFER_IN_PROGRESS = 0x8,
+    CXL_MBOX_FW_XFER_OUT_OF_ORDER = 0x9,
+    CXL_MBOX_FW_AUTH_FAILED = 0xa,
+    CXL_MBOX_FW_INVALID_SLOT = 0xb,
+    CXL_MBOX_FW_ROLLEDBACK = 0xc,
+    CXL_MBOX_FW_REST_REQD = 0xd,
+    CXL_MBOX_INVALID_HANDLE = 0xe,
+    CXL_MBOX_INVALID_PA = 0xf,
+    CXL_MBOX_INJECT_POISON_LIMIT = 0x10,
+    CXL_MBOX_PERMANENT_MEDIA_FAILURE = 0x11,
+    CXL_MBOX_ABORTED = 0x12,
+    CXL_MBOX_INVALID_SECURITY_STATE = 0x13,
+    CXL_MBOX_INCORRECT_PASSPHRASE = 0x14,
+    CXL_MBOX_UNSUPPORTED_MAILBOX = 0x15,
+    CXL_MBOX_INVALID_PAYLOAD_LENGTH = 0x16,
+    CXL_MBOX_MAX = 0x17
+} ret_code;
+
+struct cxl_cmd;
+typedef ret_code (*opcode_handler)(struct cxl_cmd *cmd,
+                                   CXLDeviceState *cxl_dstate, uint16_t *len);
+struct cxl_cmd {
+    const char *name;
+    opcode_handler handler;
+    ssize_t in;
+    uint16_t effect; /* Reported in CEL */
+    uint8_t *payload;
+};
+
+#define DEFINE_MAILBOX_HANDLER_ZEROED(name, size)                         \
+    uint16_t __zero##name = size;                                         \
+    static ret_code cmd_##name(struct cxl_cmd *cmd,                       \
+                               CXLDeviceState *cxl_dstate, uint16_t *len) \
+    {                                                                     \
+        *len = __zero##name;                                              \
+        memset(cmd->payload, 0, *len);                                    \
+        return CXL_MBOX_SUCCESS;                                          \
+    }
+#define DEFINE_MAILBOX_HANDLER_NOP(name)                                  \
+    static ret_code cmd_##name(struct cxl_cmd *cmd,                       \
+                               CXLDeviceState *cxl_dstate, uint16_t *len) \
+    {                                                                     \
+        return CXL_MBOX_SUCCESS;                                          \
+    }
+
+static QemuUUID cel_uuid;
+
+static struct cxl_cmd cxl_cmd_set[256][256] = {};
+
+void cxl_process_mailbox(CXLDeviceState *cxl_dstate)
+{
+    uint16_t ret = CXL_MBOX_SUCCESS;
+    struct cxl_cmd *cxl_cmd;
+    uint64_t status_reg;
+    opcode_handler h;
+    uint64_t command_reg = cxl_dstate->mbox_reg_state64[R_CXL_DEV_MAILBOX_CMD];
+
+    uint8_t set = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND_SET);
+    uint8_t cmd = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND);
+    uint16_t len = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD, LENGTH);
+    cxl_cmd = &cxl_cmd_set[set][cmd];
+    h = cxl_cmd->handler;
+    if (h) {
+        if (len == cxl_cmd->in) {
+            cxl_cmd->payload = cxl_dstate->mbox_reg_state +
+                A_CXL_DEV_CMD_PAYLOAD;
+            ret = (*h)(cxl_cmd, cxl_dstate, &len);
+            assert(len <= cxl_dstate->payload_size);
+        } else {
+            ret = CXL_MBOX_INVALID_PAYLOAD_LENGTH;
+        }
+    } else {
+        qemu_log_mask(LOG_UNIMP, "Command %04xh not implemented\n",
+                      set << 8 | cmd);
+        ret = CXL_MBOX_UNSUPPORTED;
+    }
+
+    /* Set the return code */
+    status_reg = FIELD_DP64(0, CXL_DEV_MAILBOX_STS, ERRNO, ret);
+
+    /* Set the return length */
+    command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND_SET, 0);
+    command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND, 0);
+    command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD, LENGTH, len);
+
+    cxl_dstate->mbox_reg_state64[R_CXL_DEV_MAILBOX_CMD] = command_reg;
+    cxl_dstate->mbox_reg_state64[R_CXL_DEV_MAILBOX_STS] = status_reg;
+
+    /* Tell the host we're done */
+    ARRAY_FIELD_DP32(cxl_dstate->mbox_reg_state32, CXL_DEV_MAILBOX_CTRL,
+                     DOORBELL, 0);
+}
+
+int cxl_initialize_mailbox(CXLDeviceState *cxl_dstate)
+{
+    /* CXL 2.0: Table 169 Get Supported Logs Log Entry */
+    const char *cel_uuidstr = "0da9c0b5-bf41-4b78-8f79-96b1623b3f17";
+
+    for (int set = 0; set < 256; set++) {
+        for (int cmd = 0; cmd < 256; cmd++) {
+            if (cxl_cmd_set[set][cmd].handler) {
+                struct cxl_cmd *c = &cxl_cmd_set[set][cmd];
+                struct cel_log *log =
+                    &cxl_dstate->cel_log[cxl_dstate->cel_size];
+
+                log->opcode = (set << 8) | cmd;
+                log->effect = c->effect;
+                cxl_dstate->cel_size++;
+            }
+        }
+    }
+
+    return qemu_uuid_parse(cel_uuidstr, &cel_uuid);
+}