backends/igvm: Add IGVM loader and configuration

Adds an IGVM loader to QEMU which processes a given IGVM file and
applies the directives within the file to the current guest
configuration.

The IGVM loader can be used to configure both confidential and
non-confidential guests. For confidential guests, the
ConfidentialGuestSupport object for the system is used to encrypt
memory, apply the initial CPU state and perform other confidential guest
operations.

The loader is configured via a new IgvmCfg QOM object which allows the
user to provide a path to the IGVM file to process.

Signed-off-by: Roy Hopkins <roy.hopkins@randomman.co.uk>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gerd Hoffman <kraxel@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/ae3a07d8f514d93845a9c16bb155c847cb567b0d.1751554099.git.roy.hopkins@randomman.co.uk
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/include/system/igvm-cfg.h b/include/system/igvm-cfg.h
new file mode 100644
index 0000000000..321b3196f0
--- /dev/null
+++ b/include/system/igvm-cfg.h
@@ -0,0 +1,46 @@
+/*
+ * QEMU IGVM interface
+ *
+ * Copyright (C) 2024 SUSE
+ *
+ * Authors:
+ *  Roy Hopkins <roy.hopkins@randomman.co.uk>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_IGVM_CFG_H
+#define QEMU_IGVM_CFG_H
+
+#include "qom/object.h"
+
+typedef struct IgvmCfg {
+    ObjectClass parent_class;
+
+    /*
+     * filename: Filename that specifies a file that contains the configuration
+     *           of the guest in Independent Guest Virtual Machine (IGVM)
+     *           format.
+     */
+    char *filename;
+} IgvmCfg;
+
+typedef struct IgvmCfgClass {
+    ObjectClass parent_class;
+
+    /*
+     * If an IGVM filename has been specified then process the IGVM file.
+     * Performs a no-op if no filename has been specified.
+     *
+     * Returns 0 for ok and -1 on error.
+     */
+    int (*process)(IgvmCfg *cfg, ConfidentialGuestSupport *cgs,
+                   Error **errp);
+
+} IgvmCfgClass;
+
+#define TYPE_IGVM_CFG "igvm-cfg"
+
+OBJECT_DECLARE_TYPE(IgvmCfg, IgvmCfgClass, IGVM_CFG)
+
+#endif