[PATCH v4 03/13] common/hyperlaunch: introduce the domain builder

[Alejandro Vallejo <agarciav@xxxxxxx>]

From: "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>
Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
Signed-off-by: Alejandro Vallejo <agarciav@xxxxxxx>
---
v4:
  * Moved from arch/x86/ to common/
  * gated all of domain-builder/ on CONFIG_BOOT_INFO
  * Hide the domain builder submenu for !X86
  * Factor out the "hyperlaunch_enabled = false" toggle core.c
  * Removed stub inline, as DCE makes it unnecessary
  * Adjusted printks.
---
 xen/arch/x86/include/asm/bootinfo.h |  3 ++
 xen/arch/x86/setup.c                | 17 +++++----
 xen/common/Makefile                 |  1 +
 xen/common/domain-builder/Makefile  |  2 ++
 xen/common/domain-builder/core.c    | 56 +++++++++++++++++++++++++++++
 xen/common/domain-builder/fdt.c     | 37 +++++++++++++++++++
 xen/common/domain-builder/fdt.h     | 12 +++++++
 xen/include/xen/domain-builder.h    |  9 +++++
 8 files changed, 131 insertions(+), 6 deletions(-)
 create mode 100644 xen/common/domain-builder/Makefile
 create mode 100644 xen/common/domain-builder/core.c
 create mode 100644 xen/common/domain-builder/fdt.c
 create mode 100644 xen/common/domain-builder/fdt.h
 create mode 100644 xen/include/xen/domain-builder.h

diff --git a/xen/arch/x86/include/asm/bootinfo.h 
b/xen/arch/x86/include/asm/bootinfo.h
index 3afc214c17..82c2650fcf 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/setup.c b/xen/arch/x86/setup.c
index 4df012460d..ccc57cc70a 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -5,6 +5,7 @@
 #include <xen/cpuidle.h>
 #include <xen/dmi.h>
 #include <xen/domain.h>
+#include <xen/domain-builder.h>
 #include <xen/domain_page.h>
 #include <xen/efi.h>
 #include <xen/err.h>
@@ -1282,9 +1283,12 @@ 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 )
     {
@@ -1467,8 +1471,9 @@ 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);
+    bi->domains[0].kernel->headroom =
+        bzimage_headroom(bootstrap_map_bm(bi->domains[0].kernel),
+                         bi->domains[0].kernel->size);
     bootstrap_unmap();
 
 #ifndef highmem_start
@@ -1592,7 +1597,7 @@ void asmlinkage __init noreturn __start_xen(void)
 #endif
     }
 
-    if ( bi->mods[0].headroom && !bi->mods[0].relocated )
+    if ( bi->domains[0].kernel->headroom && !bi->domains[0].kernel->relocated )
         panic("Not enough memory to relocate the dom0 kernel image\n");
     for ( i = 0; i < bi->nr_modules; ++i )
     {
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 98f0873056..565837bc71 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -11,6 +11,7 @@ obj-$(filter-out $(CONFIG_X86),$(CONFIG_ACPI)) += device.o
 obj-$(CONFIG_HAS_DEVICE_TREE) += device-tree/
 obj-$(CONFIG_IOREQ_SERVER) += dm.o
 obj-y += domain.o
+obj-$(CONFIG_HAS_BOOT_INFO) += domain-builder/
 obj-y += event_2l.o
 obj-y += event_channel.o
 obj-$(CONFIG_EVTCHN_FIFO) += event_fifo.o
diff --git a/xen/common/domain-builder/Makefile 
b/xen/common/domain-builder/Makefile
new file mode 100644
index 0000000000..b10cd56b28
--- /dev/null
+++ b/xen/common/domain-builder/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_DOMAIN_BUILDER) += fdt.init.o
+obj-y += core.init.o
diff --git a/xen/common/domain-builder/core.c b/xen/common/domain-builder/core.c
new file mode 100644
index 0000000000..a5b21fc179
--- /dev/null
+++ b/xen/common/domain-builder/core.c
@@ -0,0 +1,56 @@
+/* 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)
+{
+    bi->hyperlaunch_enabled = false;
+
+    if ( IS_ENABLED(CONFIG_DOMAIN_BUILDER) )
+    {
+        int ret;
+
+        switch ( ret = has_hyperlaunch_fdt(bi) )
+        {
+        case 0:
+            printk(XENLOG_DEBUG "DT found: hyperlaunch\n");
+            bi->hyperlaunch_enabled = true;
+            bi->mods[0].type = BOOTMOD_FDT;
+            break;
+
+        case -EINVAL:
+            /* No DT found */
+            break;
+
+        case -ENOENT:
+        case -ENODATA:
+            printk(XENLOG_DEBUG "DT found: non-hyperlaunch (%d)\n", ret);
+            bi->mods[0].type = BOOTMOD_FDT;
+            break;
+
+        default:
+            printk(XENLOG_ERR "unknown error (%d) checking hyperlaunch DT\n",
+                   ret);
+            break;
+        }
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/domain-builder/fdt.c b/xen/common/domain-builder/fdt.c
new file mode 100644
index 0000000000..aaf8c1cc16
--- /dev/null
+++ b/xen/common/domain-builder/fdt.c
@@ -0,0 +1,37 @@
+/* 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 <asm/bootinfo.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+
+#include "fdt.h"
+
+int __init has_hyperlaunch_fdt(const struct boot_info *bi)
+{
+    int ret = 0;
+    const void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
+
+    if ( !fdt || 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/common/domain-builder/fdt.h b/xen/common/domain-builder/fdt.h
new file mode 100644
index 0000000000..97a45a6ec4
--- /dev/null
+++ b/xen/common/domain-builder/fdt.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __XEN_DOMAIN_BUILDER_FDT_H__
+#define __XEN_DOMAIN_BUILDER_FDT_H__
+
+struct boot_info;
+
+/* hyperlaunch fdt is required to be module 0 */
+#define HYPERLAUNCH_MODULE_IDX 0
+
+int has_hyperlaunch_fdt(const struct boot_info *bi);
+
+#endif /* __XEN_DOMAIN_BUILDER_FDT_H__ */
diff --git a/xen/include/xen/domain-builder.h b/xen/include/xen/domain-builder.h
new file mode 100644
index 0000000000..ac2b84775d
--- /dev/null
+++ b/xen/include/xen/domain-builder.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __XEN_DOMAIN_BUILDER_H__
+#define __XEN_DOMAIN_BUILDER_H__
+
+struct boot_info;
+
+void builder_init(struct boot_info *bi);
+
+#endif /* __XEN_DOMAIN_BUILDER_H__ */
-- 
2.43.0