migration: Move migrate_caps_check() to options.c

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

1 files changed, 192 insertions, 0 deletions

diff --git a/migration/options.c b/migration/options.c
index 9c9b8e5863..367c930f46 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -12,7 +12,10 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "sysemu/runstate.h"
 #include "migration.h"
+#include "ram.h"
 #include "options.h"
 
 bool migrate_auto_converge(void)
@@ -198,3 +201,192 @@ bool migrate_zero_copy_send(void)
 
     return s->capabilities[MIGRATION_CAPABILITY_ZERO_COPY_SEND];
 }
+typedef enum WriteTrackingSupport {
+    WT_SUPPORT_UNKNOWN = 0,
+    WT_SUPPORT_ABSENT,
+    WT_SUPPORT_AVAILABLE,
+    WT_SUPPORT_COMPATIBLE
+} WriteTrackingSupport;
+
+static
+WriteTrackingSupport migrate_query_write_tracking(void)
+{
+    /* Check if kernel supports required UFFD features */
+    if (!ram_write_tracking_available()) {
+        return WT_SUPPORT_ABSENT;
+    }
+    /*
+     * Check if current memory configuration is
+     * compatible with required UFFD features.
+     */
+    if (!ram_write_tracking_compatible()) {
+        return WT_SUPPORT_AVAILABLE;
+    }
+
+    return WT_SUPPORT_COMPATIBLE;
+}
+
+/* Migration capabilities set */
+struct MigrateCapsSet {
+    int size;                       /* Capability set size */
+    MigrationCapability caps[];     /* Variadic array of capabilities */
+};
+typedef struct MigrateCapsSet MigrateCapsSet;
+
+/* Define and initialize MigrateCapsSet */
+#define INITIALIZE_MIGRATE_CAPS_SET(_name, ...)   \
+    MigrateCapsSet _name = {    \
+        .size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \
+        .caps = { __VA_ARGS__ } \
+    }
+
+/* Background-snapshot compatibility check list */
+static const
+INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
+    MIGRATION_CAPABILITY_POSTCOPY_RAM,
+    MIGRATION_CAPABILITY_DIRTY_BITMAPS,
+    MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME,
+    MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE,
+    MIGRATION_CAPABILITY_RETURN_PATH,
+    MIGRATION_CAPABILITY_MULTIFD,
+    MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER,
+    MIGRATION_CAPABILITY_AUTO_CONVERGE,
+    MIGRATION_CAPABILITY_RELEASE_RAM,
+    MIGRATION_CAPABILITY_RDMA_PIN_ALL,
+    MIGRATION_CAPABILITY_COMPRESS,
+    MIGRATION_CAPABILITY_XBZRLE,
+    MIGRATION_CAPABILITY_X_COLO,
+    MIGRATION_CAPABILITY_VALIDATE_UUID,
+    MIGRATION_CAPABILITY_ZERO_COPY_SEND);
+
+/**
+ * @migration_caps_check - check capability compatibility
+ *
+ * @old_caps: old capability list
+ * @new_caps: new capability list
+ * @errp: set *errp if the check failed, with reason
+ *
+ * Returns true if check passed, otherwise false.
+ */
+bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
+{
+    MigrationIncomingState *mis = migration_incoming_get_current();
+
+#ifndef CONFIG_LIVE_BLOCK_MIGRATION
+    if (new_caps[MIGRATION_CAPABILITY_BLOCK]) {
+        error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) "
+                   "block migration");
+        error_append_hint(errp, "Use drive_mirror+NBD instead.\n");
+        return false;
+    }
+#endif
+
+#ifndef CONFIG_REPLICATION
+    if (new_caps[MIGRATION_CAPABILITY_X_COLO]) {
+        error_setg(errp, "QEMU compiled without replication module"
+                   " can't enable COLO");
+        error_append_hint(errp, "Please enable replication before COLO.\n");
+        return false;
+    }
+#endif
+
+    if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
+        /* This check is reasonably expensive, so only when it's being
+         * set the first time, also it's only the destination that needs
+         * special support.
+         */
+        if (!old_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM] &&
+            runstate_check(RUN_STATE_INMIGRATE) &&
+            !postcopy_ram_supported_by_host(mis)) {
+            /* postcopy_ram_supported_by_host will have emitted a more
+             * detailed message
+             */
+            error_setg(errp, "Postcopy is not supported");
+            return false;
+        }
+
+        if (new_caps[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
+            error_setg(errp, "Postcopy is not compatible with ignore-shared");
+            return false;
+        }
+    }
+
+    if (new_caps[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) {
+        WriteTrackingSupport wt_support;
+        int idx;
+        /*
+         * Check if 'background-snapshot' capability is supported by
+         * host kernel and compatible with guest memory configuration.
+         */
+        wt_support = migrate_query_write_tracking();
+        if (wt_support < WT_SUPPORT_AVAILABLE) {
+            error_setg(errp, "Background-snapshot is not supported by host kernel");
+            return false;
+        }
+        if (wt_support < WT_SUPPORT_COMPATIBLE) {
+            error_setg(errp, "Background-snapshot is not compatible "
+                    "with guest memory configuration");
+            return false;
+        }
+
+        /*
+         * Check if there are any migration capabilities
+         * incompatible with 'background-snapshot'.
+         */
+        for (idx = 0; idx < check_caps_background_snapshot.size; idx++) {
+            int incomp_cap = check_caps_background_snapshot.caps[idx];
+            if (new_caps[incomp_cap]) {
+                error_setg(errp,
+                        "Background-snapshot is not compatible with %s",
+                        MigrationCapability_str(incomp_cap));
+                return false;
+            }
+        }
+    }
+
+#ifdef CONFIG_LINUX
+    if (new_caps[MIGRATION_CAPABILITY_ZERO_COPY_SEND] &&
+        (!new_caps[MIGRATION_CAPABILITY_MULTIFD] ||
+         new_caps[MIGRATION_CAPABILITY_COMPRESS] ||
+         new_caps[MIGRATION_CAPABILITY_XBZRLE] ||
+         migrate_multifd_compression() ||
+         migrate_use_tls())) {
+        error_setg(errp,
+                   "Zero copy only available for non-compressed non-TLS multifd migration");
+        return false;
+    }
+#else
+    if (new_caps[MIGRATION_CAPABILITY_ZERO_COPY_SEND]) {
+        error_setg(errp,
+                   "Zero copy currently only available on Linux");
+        return false;
+    }
+#endif
+
+    if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]) {
+        if (!new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
+            error_setg(errp, "Postcopy preempt requires postcopy-ram");
+            return false;
+        }
+
+        /*
+         * Preempt mode requires urgent pages to be sent in separate
+         * channel, OTOH compression logic will disorder all pages into
+         * different compression channels, which is not compatible with the
+         * preempt assumptions on channel assignments.
+         */
+        if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
+            error_setg(errp, "Postcopy preempt not compatible with compress");
+            return false;
+        }
+    }
+
+    if (new_caps[MIGRATION_CAPABILITY_MULTIFD]) {
+        if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
+            error_setg(errp, "Multifd is not compatible with compress");
+            return false;
+        }
+    }
+
+    return true;
+}