[Qemu-devel] [PATCH 4/7] vnvram: VNVRAM internal APIs

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

Provides VNVRAM APIs that can be used by other areas of QEMU to
provide persistent storage.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
 vnvram.c |  266 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 vnvram.h |   14 +++
 2 files changed, 280 insertions(+), 0 deletions(-)

diff --git a/vnvram.c b/vnvram.c
index 4157482..357923d 100644
--- a/vnvram.c
+++ b/vnvram.c
@@ -15,6 +15,7 @@
 #include "block/block.h"
 #include "monitor/monitor.h"
 #include "qemu/thread.h"
+#include "sysemu/sysemu.h"
 
 /*
 #define VNVRAM_DEBUG
@@ -821,3 +822,268 @@ static int vnvram_rwrequest_schedule(VNVRAMRWRequest *rwr)
 
     return rc;
 }
+
+/************************* VNVRAM APIs *******************************/
+/* VNVRAM APIs that can be used by QEMU to provide persistent storage*/
+/*********************************************************************/
+
+/*
+ * Initialize VNVRAM
+ *
+ * This must be called before any other APIs.
+ */
+int vnvram_init(void)
+{
+    qemu_mutex_init(&vnvram_rwrequests_mutex);
+    vnvram_bh = qemu_bh_new(vnvram_rwrequest_callback, NULL);
+    DPRINTF("%s: VNVRAM initialized\n", __func__);
+
+    return 0;
+}
+
+/*
+ * Create a VNVRAM instance
+ *
+ * The VNVRAM instance will use the drive with the corresponding ID as
+ * its persistent storage device.
+ */
+VNVRAM *vnvram_create(const char *drv_id, bool fail_on_invalid, int *errcode)
+{
+    int rc;
+    VNVRAM *vnvram = NULL;
+    VNVRAMDrvHdr hdr;
+    BlockDriverState *bds;
+
+    *errcode = 0;
+
+    if (runstate_check(RUN_STATE_INMIGRATE)) {
+        qerror_report(QERR_MIGRATION_ACTIVE);
+        rc = -EAGAIN;
+        goto err_exit;
+    }
+
+    bds = bdrv_find(drv_id);
+    if (!bds) {
+        qerror_report(QERR_DEVICE_NOT_FOUND, drv_id);
+        rc = -ENOENT;
+        goto err_exit;
+    }
+
+    if (bdrv_is_read_only(bds)) {
+        qerror_report(QERR_DEVICE_IS_READ_ONLY, drv_id);
+        rc = -EPERM;
+        goto err_exit;
+    }
+
+    bdrv_lock_medium(bds, true);
+
+    vnvram = vnvram_drv_find_by_id(drv_id);
+    if (vnvram) {
+        /* This VNVRAM was already created - sucess */
+        return vnvram;
+    }
+
+    vnvram = g_new0(VNVRAM, 1);
+    vnvram->drv_id = g_strdup(drv_id);
+    vnvram->bds = bds;
+
+    QLIST_INIT(&vnvram->entries_head);
+
+    rc = vnvram_drv_adjust_size(vnvram);
+    if (rc != 0) {
+        qerror_report(QERR_IO_ERROR);
+        goto err_exit;
+    }
+
+    rc = vnvram_drv_hdr_read(vnvram, (&hdr));
+    if (rc != 0) {
+        qerror_report(QERR_IO_ERROR);
+        goto err_exit;
+    }
+
+    if (vnvram_drv_hdr_is_valid(vnvram, (&hdr))) {
+        rc = vnvram_sync_from_drv(vnvram, (&hdr));
+        if (rc != 0) {
+            qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM drive sync error");
+            goto err_exit;
+        }
+
+        if (vnvram_entries_are_valid(vnvram, bdrv_getlength(vnvram->bds))) {
+            /* Sync'd VNVRAM drive looks good - success */
+            goto exit;
+        }
+    }
+
+    /* Drive data looks invalid.  Could be encrypted and we didn't get key? */
+    if (bdrv_is_encrypted(vnvram->bds)) {
+        DPRINTF("%s: VNVRAM drive is encrypted\n", __func__);
+    }
+
+    /* Either fail or reformat the drive. */
+    if (fail_on_invalid) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM drive not valid");
+        rc = -EIO;
+        goto err_exit;
+    }
+
+    rc = vnvram_drv_hdr_create_empty(vnvram);
+    if (rc != 0) {
+        qerror_report(QERR_IO_ERROR);
+        goto err_exit;
+    }
+
+exit:
+    QLIST_INSERT_HEAD(&vnvrams, vnvram, list);
+    DPRINTF("%s: VNVRAM with drive '%s' created\n", __func__, vnvram->drv_id);
+
+    return vnvram;
+
+err_exit:
+    if (vnvram) {
+        g_free(vnvram->drv_id);
+    }
+    g_free(vnvram);
+    *errcode = rc;
+
+    return NULL;
+}
+
+/*
+ * Register a VNVRAM entry
+ *
+ * The entry information will not be flushed to the drive until the next
+ * write.
+ */
+int vnvram_register_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                          uint32_t max_size)
+{
+    if (!vnvram_exists(vnvram)) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM has not been created");
+        return -EPERM;
+    }
+
+    return vnvram_register_entry_internal(vnvram, entry_name, 0, 0, max_size);
+}
+
+/*
+ * Deregister a VNVRAM entry
+ */
+int vnvram_deregister_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name)
+{
+    VNVRAMEntry *entry;
+
+    if (!vnvram_exists(vnvram)) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM has not been created");
+        return -EPERM;
+    }
+
+    QLIST_FOREACH(entry, &vnvram->entries_head, next) {
+        if (!strncmp(entry->name, (char *)entry_name, sizeof(*entry_name))) {
+            if (entry->cur_size != 0) {
+                qerror_report(ERROR_CLASS_GENERIC_ERROR,
+                              "VNVRAM entry already written to disk");
+                return -EPERM;
+            }
+            QLIST_REMOVE(entry, next);
+            g_free(entry);
+            DPRINTF("%s: Deregistered VNVRAM entry '%s'\n", __func__,
+                    (char *)entry_name);
+            return 0;
+        }
+    }
+
+    qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM entry not found");
+
+    return -ENOENT;
+}
+
+/*
+ * Read a VNVRAM blob from the specified drive entry
+ */
+int vnvram_read_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                      char **blob, uint32_t *blob_size)
+{
+    int rc;
+    VNVRAMEntry *entry;
+    VNVRAMRWRequest *rwr;
+
+    *blob = NULL;
+    *blob_size = 0;
+
+    if (!vnvram_exists(vnvram)) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM has not been created");
+        return -EPERM;
+    }
+
+    entry = vnvram_find_entry(vnvram, entry_name);
+    if (!entry) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM entry not found");
+        return -ENOENT;
+    }
+
+    rwr = vnvram_rwrequest_init_read(vnvram, entry, blob, blob_size);
+
+    rc = vnvram_rwrequest_schedule(rwr);
+
+    g_free(rwr);
+
+    return rc;
+}
+
+/*
+ * Write a VNVRAM blob to the specified drive entry
+ */
+int vnvram_write_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                       char *blob, uint32_t blob_size)
+{
+    int rc;
+    VNVRAMEntry *entry;
+    VNVRAMRWRequest *rwr;
+
+    if (!vnvram_exists(vnvram)) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM has not been created");
+        return -EPERM;
+    }
+
+    entry = vnvram_find_entry(vnvram, entry_name);
+    if (!entry) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM entry not found");
+        return -ENOENT;
+    }
+
+    rwr = vnvram_rwrequest_init_write(vnvram, entry, blob, blob_size);
+
+    rc = vnvram_rwrequest_schedule(rwr);
+
+    g_free(rwr);
+
+    return rc;
+}
+
+/*
+ * Delete a VNVRAM from memory
+ */
+int vnvram_delete(VNVRAM *vnvram)
+{
+    VNVRAMEntry *entry;
+
+    if (!vnvram_exists(vnvram)) {
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "VNVRAM has not been created");
+        return -EPERM;
+    }
+
+    QLIST_FOREACH(entry, &vnvram->entries_head, next) {
+        QLIST_REMOVE(entry, next);
+        g_free(entry);
+    }
+
+    QLIST_REMOVE(vnvram, list);
+
+    DPRINTF("%s: VNVRAM with drive '%s' deleted from memory\n",
+            __func__, vnvram->drv_id);
+
+    g_free(vnvram->drv_id);
+    g_free(vnvram);
+
+    return 0;
+}
diff --git a/vnvram.h b/vnvram.h
index b6d7cd7..c1055b4 100644
--- a/vnvram.h
+++ b/vnvram.h
@@ -14,9 +14,23 @@
 #ifndef _QEMU_VNVRAM_H_
 #define _QEMU_VNVRAM_H_
 
+#include <stdint.h>
+#include <stdbool.h>
+
 typedef struct VNVRAM VNVRAM;
 
 #define VNVRAM_ENTRY_NAME_LENGTH 16
 typedef char VNVRAMEntryName[VNVRAM_ENTRY_NAME_LENGTH];
 
+int vnvram_init(void);
+VNVRAM *vnvram_create(const char *drv_id, bool fail_on_invalid, int *errcode);
+int vnvram_register_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                          uint32_t max_size);
+int vnvram_deregister_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name);
+int vnvram_read_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                      char **blob, uint32_t *blob_size);
+int vnvram_write_entry(VNVRAM *vnvram, const VNVRAMEntryName *entry_name,
+                       char *blob, uint32_t blob_size);
+int vnvram_delete(VNVRAM *vnvram);
+
 #endif
-- 
1.7.1