[PATCH 06/15] x86/hyperlaunch: introduce the domain builder

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

Introduce the domain builder which is capable of consuming a device tree as the
first boot module. If it finds a device tree as the first boot module, it will
set its type to BOOTMOD_FDT. This change only detects the boot module and
continues to boot with slight change to the boot convention that the dom0
kernel is no longer first boot module but is the second.

No functional change intended.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 xen/arch/x86/Makefile                    |  2 +
 xen/arch/x86/domain_builder/Makefile     |  3 ++
 xen/arch/x86/domain_builder/core.c       | 55 ++++++++++++++++++++++++
 xen/arch/x86/domain_builder/fdt.c        | 38 ++++++++++++++++
 xen/arch/x86/domain_builder/fdt.h        | 21 +++++++++
 xen/arch/x86/include/asm/bootinfo.h      |  3 ++
 xen/arch/x86/include/asm/domainbuilder.h |  8 ++++
 xen/arch/x86/setup.c                     | 18 +++++---
 8 files changed, 142 insertions(+), 6 deletions(-)
 create mode 100644 xen/arch/x86/domain_builder/Makefile
 create mode 100644 xen/arch/x86/domain_builder/core.c
 create mode 100644 xen/arch/x86/domain_builder/fdt.c
 create mode 100644 xen/arch/x86/domain_builder/fdt.h
 create mode 100644 xen/arch/x86/include/asm/domainbuilder.h

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index b35fd5196ce2..45e4c963edcd 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -81,6 +81,8 @@ obj-$(CONFIG_COMPAT) += x86_64/platform_hypercall.o
 obj-y += sysctl.o
 endif
 
+obj-y += domain_builder/
+
 extra-y += asm-macros.i
 extra-y += xen.lds
 
diff --git a/xen/arch/x86/domain_builder/Makefile 
b/xen/arch/x86/domain_builder/Makefile
new file mode 100644
index 000000000000..309a0c4bdd9e
--- /dev/null
+++ b/xen/arch/x86/domain_builder/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_DOMAIN_BUILDER) += fdt.init.o
+obj-y += core.init.o
+
diff --git a/xen/arch/x86/domain_builder/core.c 
b/xen/arch/x86/domain_builder/core.c
new file mode 100644
index 000000000000..211359895d84
--- /dev/null
+++ b/xen/arch/x86/domain_builder/core.c
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024, Apertus Solutions, LLC
+ */
+#include <xen/err.h>
+#include <xen/init.h>
+#include <xen/kconfig.h>
+#include <xen/lib.h>
+
+#include <asm/bootinfo.h>
+
+#include "fdt.h"
+
+void __init builder_init(struct boot_info *bi)
+{
+    if ( IS_ENABLED(CONFIG_DOMAIN_BUILDER) )
+    {
+        int ret;
+
+        switch ( ret = has_hyperlaunch_fdt(bi) )
+        {
+        case 0:
+            printk("Hyperlaunch device tree detected\n");
+            bi->hyperlaunch_enabled = true;
+            bi->mods[0].type = BOOTMOD_FDT;
+            break;
+        case -EINVAL:
+            printk("Hyperlaunch device tree was not detected\n");
+            bi->hyperlaunch_enabled = false;
+            break;
+        case -ENOENT:
+            fallthrough;
+        case -ENODATA:
+            printk("Device tree found, but not hyperlaunch (%d)\n", ret);
+            bi->hyperlaunch_enabled = false;
+            bi->mods[0].type = BOOTMOD_FDT;
+            break;
+        default:
+            printk("Unknown error (%d) occured checking for hyperlaunch device 
tree\n",
+                   ret);
+            bi->hyperlaunch_enabled = false;
+        }
+
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/domain_builder/fdt.c 
b/xen/arch/x86/domain_builder/fdt.c
new file mode 100644
index 000000000000..3f9dda8c34c3
--- /dev/null
+++ b/xen/arch/x86/domain_builder/fdt.c
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024, Apertus Solutions, LLC
+ */
+#include <xen/err.h>
+#include <xen/init.h>
+#include <xen/lib.h>
+#include <xen/libfdt/libfdt.h>
+#include <xen/rangeset.h> /* required for asm/setup.h */
+
+#include <asm/bootinfo.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+
+#include "fdt.h"
+
+int __init has_hyperlaunch_fdt(struct boot_info *bi)
+{
+    int ret = 0;
+    void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
+
+    if ( fdt_check_header(fdt) < 0 )
+        ret = -EINVAL;
+
+    bootstrap_unmap();
+
+    return ret;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/domain_builder/fdt.h 
b/xen/arch/x86/domain_builder/fdt.h
new file mode 100644
index 000000000000..1c1569a9c633
--- /dev/null
+++ b/xen/arch/x86/domain_builder/fdt.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
+#ifndef __XEN_X86_FDT_H__
+#define __XEN_X86_FDT_H__
+
+#include <xen/init.h>
+
+#include <asm/bootinfo.h>
+
+/* hyperlaunch fdt is required to be module 0 */
+#define HYPERLAUNCH_MODULE_IDX 0
+
+#ifdef CONFIG_DOMAIN_BUILDER
+int has_hyperlaunch_fdt(struct boot_info *bi);
+#else
+static inline int __init has_hyperlaunch_fdt(struct boot_info *bi)
+{
+    return -EINVAL;
+}
+#endif
+
+#endif /* __XEN_X86_FDT_H__ */
diff --git a/xen/arch/x86/include/asm/bootinfo.h 
b/xen/arch/x86/include/asm/bootinfo.h
index 9f65e2c8f62d..208bec90913d 100644
--- a/xen/arch/x86/include/asm/bootinfo.h
+++ b/xen/arch/x86/include/asm/bootinfo.h
@@ -27,6 +27,7 @@ enum bootmod_type {
     BOOTMOD_RAMDISK,
     BOOTMOD_MICROCODE,
     BOOTMOD_XSM_POLICY,
+    BOOTMOD_FDT,
 };
 
 struct boot_module {
@@ -80,6 +81,8 @@ struct boot_info {
     paddr_t memmap_addr;
     size_t memmap_length;
 
+    bool hyperlaunch_enabled;
+
     unsigned int nr_modules;
     struct boot_module mods[MAX_NR_BOOTMODS + 1];
     struct boot_domain domains[MAX_NR_BOOTDOMS];
diff --git a/xen/arch/x86/include/asm/domainbuilder.h 
b/xen/arch/x86/include/asm/domainbuilder.h
new file mode 100644
index 000000000000..aedc2b49f7c9
--- /dev/null
+++ b/xen/arch/x86/include/asm/domainbuilder.h
@@ -0,0 +1,8 @@
+#ifndef __XEN_X86_DOMBUILDER_H__
+#define __XEN_X86_DOMBUILDER_H__
+
+#include <asm/bootinfo.h>
+
+void builder_init(struct boot_info *bi);
+
+#endif
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index e6580382d247..8041aeb3dcfd 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -33,6 +33,7 @@
 #endif
 #include <xen/bitops.h>
 #include <asm/bootinfo.h>
+#include <asm/domainbuilder.h>
 #include <asm/smp.h>
 #include <asm/processor.h>
 #include <asm/mpspec.h>
@@ -1277,9 +1278,12 @@ void asmlinkage __init noreturn __start_xen(void)
                bi->nr_modules);
     }
 
-    /* Dom0 kernel is always first */
-    bi->mods[0].type = BOOTMOD_KERNEL;
-    bi->domains[0].kernel = &bi->mods[0];
+    builder_init(bi);
+
+    /* Find first unknown boot module to use as Dom0 kernel */
+    i = first_boot_module_index(bi, BOOTMOD_UNKNOWN);
+    bi->mods[i].type = BOOTMOD_KERNEL;
+    bi->domains[0].kernel = &bi->mods[i];
 
     if ( pvh_boot )
     {
@@ -1466,8 +1470,9 @@ void asmlinkage __init noreturn __start_xen(void)
         xen->size  = __2M_rwdata_end - _stext;
     }
 
-    bi->mods[0].headroom =
-        bzimage_headroom(bootstrap_map_bm(&bi->mods[0]), bi->mods[0].size);
+    i = first_boot_module_index(bi, BOOTMOD_KERNEL);
+    bi->mods[i].headroom =
+        bzimage_headroom(bootstrap_map_bm(&bi->mods[i]), bi->mods[i].size);
     bootstrap_unmap();
 
 #ifndef highmem_start
@@ -1591,7 +1596,8 @@ void asmlinkage __init noreturn __start_xen(void)
 #endif
     }
 
-    if ( bi->mods[0].headroom && !bi->mods[0].relocated )
+    i = first_boot_module_index(bi, BOOTMOD_KERNEL);
+    if ( bi->mods[i].headroom && !bi->mods[0].relocated )
         panic("Not enough memory to relocate the dom0 kernel image\n");
     for ( i = 0; i < bi->nr_modules; ++i )
     {
-- 
2.30.2