diff mbox series

[v1,11/18] x86: initial conversion to domain builder

Message ID 20220706210454.30096-12-dpsmith@apertussolutions.com (mailing list archive)
State New, archived
Headers show
Series Hyperlaunch | expand

Commit Message

Daniel P. Smith July 6, 2022, 9:04 p.m. UTC
This commit is the first step in adopting domain builder. It goes through the
dom0 creation and construction functions, converting them over to consume
struct boot_domaain and changes the startup sequence to use the domain builder
to create and construct dom0.

Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Christopher Clark <christopher.clark@starlab.io>
---
 xen/arch/x86/dom0_build.c             |  30 +++----
 xen/arch/x86/hvm/dom0_build.c         |  10 +--
 xen/arch/x86/include/asm/dom0_build.h |   8 +-
 xen/arch/x86/include/asm/setup.h      |   5 +-
 xen/arch/x86/pv/dom0_build.c          |  39 ++++-----
 xen/arch/x86/setup.c                  | 114 +++++++++++++++-----------
 6 files changed, 109 insertions(+), 97 deletions(-)

Comments

Jan Beulich July 26, 2022, 3:01 p.m. UTC | #1
On 06.07.2022 23:04, Daniel P. Smith wrote:
> This commit is the first step in adopting domain builder. It goes through the
> dom0 creation and construction functions, converting them over to consume
> struct boot_domaain and changes the startup sequence to use the domain builder
> to create and construct dom0.
> 
> Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
> Reviewed-by: Christopher Clark <christopher.clark@starlab.io>
> ---
>  xen/arch/x86/dom0_build.c             |  30 +++----
>  xen/arch/x86/hvm/dom0_build.c         |  10 +--
>  xen/arch/x86/include/asm/dom0_build.h |   8 +-
>  xen/arch/x86/include/asm/setup.h      |   5 +-
>  xen/arch/x86/pv/dom0_build.c          |  39 ++++-----
>  xen/arch/x86/setup.c                  | 114 +++++++++++++++-----------
>  6 files changed, 109 insertions(+), 97 deletions(-)
> 
> diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
> index e44f7f3c43..216c9e3590 100644
> --- a/xen/arch/x86/dom0_build.c
> +++ b/xen/arch/x86/dom0_build.c
> @@ -6,6 +6,7 @@
>  
>  #include <xen/bootdomain.h>
>  #include <xen/bootinfo.h>
> +#include <xen/domain_builder.h>
>  #include <xen/init.h>
>  #include <xen/iocap.h>
>  #include <xen/libelf.h>
> @@ -556,31 +557,32 @@ int __init dom0_setup_permissions(struct domain *d)
>      return rc;
>  }
>  
> -int __init construct_dom0(
> -    struct domain *d, const struct boot_module *image,
> -    struct boot_module *initrd, char *cmdline)
> +int __init construct_domain(struct boot_domain *bd)
>  {
> -    int rc;
> +    int rc = 0;
>  
>      /* Sanity! */
> -    BUG_ON(!pv_shim && d->domain_id != 0);
> -    BUG_ON(d->vcpu[0] == NULL);
> -    BUG_ON(d->vcpu[0]->is_initialised);
> +    BUG_ON(!pv_shim && bd->domid != 0);
> +    BUG_ON(bd->domain->vcpu[0] == NULL);
> +    BUG_ON(bd->domain->vcpu[0]->is_initialised);
>  
>      process_pending_softirqs();
>  
> -    if ( is_hvm_domain(d) )
> -        rc = dom0_construct_pvh(d, image, initrd, cmdline);
> -    else if ( is_pv_domain(d) )
> -        rc = dom0_construct_pv(d, image, initrd, cmdline);
> -    else
> -        panic("Cannot construct Dom0. No guest interface available\n");
> +    if ( builder_is_initdom(bd) )
> +    {
> +        if ( is_hvm_domain(bd->domain) )
> +            rc = dom0_construct_pvh(bd);
> +        else if ( is_pv_domain(bd->domain) )
> +            rc = dom0_construct_pv(bd);
> +        else
> +            panic("Cannot construct Dom0. No guest interface available\n");
> +    }

Isn't there an "else" missing here, even if just to ASSERT_UNREACHABLE()
and set rc to, say, -EOPNOTSUPP?

> @@ -311,11 +310,12 @@ int __init dom0_construct_pv(
>      unsigned long count;
>      struct page_info *page = NULL;
>      start_info_t *si;
> +    struct domain *d = bd->domain;
>      struct vcpu *v = d->vcpu[0];
> -    void *image_base = bootstrap_map(image);
> -    unsigned long image_len = image->size;
> -    void *image_start = image_base + image->arch->headroom;
> -    unsigned long initrd_len = initrd ? initrd->size : 0;
> +    void *image_base = bootstrap_map(bd->kernel);
> +    unsigned long image_len = bd->kernel->size;
> +    void *image_start = image_base + bd->kernel->arch->headroom;
> +    unsigned long initrd_len = bd->ramdisk ? bd->ramdisk->size : 0;
>      l4_pgentry_t *l4tab = NULL, *l4start = NULL;
>      l3_pgentry_t *l3tab = NULL, *l3start = NULL;
>      l2_pgentry_t *l2tab = NULL, *l2start = NULL;
> @@ -355,7 +355,7 @@ int __init dom0_construct_pv(
>      d->max_pages = ~0U;
>  
>      if ( (rc =
> -          bzimage_parse(image_base, &image_start, image->arch->headroom,
> +          bzimage_parse(image_base, &image_start, bd->kernel->arch->headroom,
>                           &image_len)) != 0 )
>          return rc;
>  
> @@ -545,7 +545,7 @@ int __init dom0_construct_pv(
>          initrd_pfn = vinitrd_start ?
>                       (vinitrd_start - v_start) >> PAGE_SHIFT :
>                       domain_tot_pages(d);
> -        initrd_mfn = mfn = mfn_x(initrd->mfn);
> +        initrd_mfn = mfn = mfn_x(bd->ramdisk->mfn);
>          count = PFN_UP(initrd_len);
>          if ( d->arch.physaddr_bitsize &&
>               ((mfn + count - 1) >> (d->arch.physaddr_bitsize - PAGE_SHIFT)) )
> @@ -560,13 +560,13 @@ int __init dom0_construct_pv(
>                      free_domheap_pages(page, order);
>                      page += 1UL << order;
>                  }
> -            memcpy(page_to_virt(page), maddr_to_virt(initrd->start),
> +            memcpy(page_to_virt(page), maddr_to_virt(bd->ramdisk->start),
>                     initrd_len);
> -            mpt_alloc = initrd->start;
> +            mpt_alloc = bd->ramdisk->start;
>              init_domheap_pages(mpt_alloc,
>                                 mpt_alloc + PAGE_ALIGN(initrd_len));
> -            bootmodule_update_mfn(initrd, page_to_mfn(page));
> -            initrd_mfn = mfn_x(initrd->mfn);
> +            bootmodule_update_mfn(bd->ramdisk, page_to_mfn(page));
> +            initrd_mfn = mfn_x(bd->ramdisk->mfn);
>          }
>          else
>          {
> @@ -574,7 +574,7 @@ int __init dom0_construct_pv(
>                  if ( assign_pages(mfn_to_page(_mfn(mfn++)), 1, d, 0) )
>                      BUG();
>          }
> -        initrd->size = 0;
> +        bd->ramdisk->size = 0;

From an abstract pov: Is it legitimate to alter values under bd-> ? I
would have assumed bd and everything under it is r/o at this point
(and could/should be const-qualified).

> @@ -272,6 +271,24 @@ static int __init cf_check parse_acpi_param(const char *s)
>  }
>  custom_param("acpi", parse_acpi_param);
>  
> +void __init arch_builder_apply_cmdline(
> +    struct boot_info *info, struct boot_domain *bd)
> +{
> +    if ( skip_ioapic_setup && !strstr(bd->kernel->string.bytes, "noapic") )
> +        strlcat(bd->kernel->string.bytes, " noapic", MAX_GUEST_CMDLINE);
> +    if ( (strlen(acpi_param) == 0) && acpi_disabled )
> +    {
> +        printk("ACPI is disabled, notifying Domain 0 (acpi=off)\n");
> +        strlcpy(acpi_param, "off", sizeof(acpi_param));
> +    }
> +    if ( (strlen(acpi_param) != 0) &&
> +         !strstr(bd->kernel->string.bytes, "acpi=") )
> +    {
> +        strlcat(bd->kernel->string.bytes, " acpi=", MAX_GUEST_CMDLINE);
> +        strlcat(bd->kernel->string.bytes, acpi_param, MAX_GUEST_CMDLINE);
> +    }
> +}

This duplicates existing code rather than replacing it. How do
you envision the two to remain in sync? Such things should live in
exactly one place imo.

> @@ -816,7 +831,7 @@ static struct domain *__init create_dom0(const struct boot_info *bi)
>          write_cr4(read_cr4() & ~X86_CR4_SMAP);
>      }
>  
> -    if ( construct_dom0(d, image, initrd, cmdline) != 0 )
> +    if ( construct_domain(bd) != 0 )
>          panic("Could not construct domain 0\n");

You leave the log message text in place here, but ...

> @@ -1905,22 +1912,29 @@ void __init noreturn __start_xen(unsigned long bi_p)
>             cpu_has_nx ? XENLOG_INFO : XENLOG_WARNING "Warning: ",
>             cpu_has_nx ? "" : "not ");
>  
> -    initrdidx = bootmodule_next_idx_by_kind(boot_info, BOOTMOD_UNKNOWN, 0);
> -    if ( initrdidx < boot_info->nr_mods )
> -        boot_info->mods[initrdidx].kind = BOOTMOD_RAMDISK;
> -
> -    if ( bootmodule_count_by_kind(boot_info, BOOTMOD_UNKNOWN) > 1 )
> -        printk(XENLOG_WARNING
> -               "Multiple initrd candidates, picking module #%u\n",
> -               initrdidx);
> -
>      /*
> -     * We're going to setup domain0 using the module(s) that we stashed safely
> -     * above our heap. The second module, if present, is an initrd ramdisk.
> +     * Boot description not provided, check to see if there are any remaining
> +     * boot modules, the first one found will be provided as the ramdisk.
>       */
> -    dom0 = create_dom0(boot_info);
> +    if ( ! boot_info->builder->fdt_enabled )
> +    {
> +        initrdidx = bootmodule_next_idx_by_kind(boot_info, BOOTMOD_UNKNOWN, 0);
> +        if ( initrdidx < boot_info->nr_mods )
> +        {
> +            boot_info->builder->domains[0].ramdisk = &boot_info->mods[initrdidx];
> +            boot_info->mods[initrdidx].kind = BOOTMOD_RAMDISK;
> +        }
> +        if ( bootmodule_count_by_kind(boot_info, BOOTMOD_UNKNOWN) > 1 )
> +            printk(XENLOG_WARNING
> +                   "Multiple initrd candidates, picking module #%u\n",
> +                   initrdidx);
> +    }
> +
> +    builder_create_domains(boot_info);
> +
> +    dom0 = builder_get_hwdom(boot_info);
>      if ( !dom0 )
> -        panic("Could not set up DOM0 guest OS\n");
> +        panic("No hardware domain was built\n");

... you change it here, neglecting that in the late-hwdom case what is
being built here is only Dom0, not hwdom. This may also affect the name
of the function that you call.

Jan
diff mbox series

Patch

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index e44f7f3c43..216c9e3590 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -6,6 +6,7 @@ 
 
 #include <xen/bootdomain.h>
 #include <xen/bootinfo.h>
+#include <xen/domain_builder.h>
 #include <xen/init.h>
 #include <xen/iocap.h>
 #include <xen/libelf.h>
@@ -556,31 +557,32 @@  int __init dom0_setup_permissions(struct domain *d)
     return rc;
 }
 
-int __init construct_dom0(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline)
+int __init construct_domain(struct boot_domain *bd)
 {
-    int rc;
+    int rc = 0;
 
     /* Sanity! */
-    BUG_ON(!pv_shim && d->domain_id != 0);
-    BUG_ON(d->vcpu[0] == NULL);
-    BUG_ON(d->vcpu[0]->is_initialised);
+    BUG_ON(!pv_shim && bd->domid != 0);
+    BUG_ON(bd->domain->vcpu[0] == NULL);
+    BUG_ON(bd->domain->vcpu[0]->is_initialised);
 
     process_pending_softirqs();
 
-    if ( is_hvm_domain(d) )
-        rc = dom0_construct_pvh(d, image, initrd, cmdline);
-    else if ( is_pv_domain(d) )
-        rc = dom0_construct_pv(d, image, initrd, cmdline);
-    else
-        panic("Cannot construct Dom0. No guest interface available\n");
+    if ( builder_is_initdom(bd) )
+    {
+        if ( is_hvm_domain(bd->domain) )
+            rc = dom0_construct_pvh(bd);
+        else if ( is_pv_domain(bd->domain) )
+            rc = dom0_construct_pv(bd);
+        else
+            panic("Cannot construct Dom0. No guest interface available\n");
+    }
 
     if ( rc )
         return rc;
 
     /* Sanity! */
-    BUG_ON(!d->vcpu[0]->is_initialised);
+    BUG_ON(!bd->domain->vcpu[0]->is_initialised);
 
     return 0;
 }
diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index 4e903a848d..2fee2ed926 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -19,6 +19,7 @@ 
  */
 
 #include <xen/acpi.h>
+#include <xen/bootdomain.h>
 #include <xen/bootinfo.h>
 #include <xen/init.h>
 #include <xen/libelf.h>
@@ -1217,10 +1218,9 @@  static void __hwdom_init pvh_setup_mmcfg(struct domain *d)
     }
 }
 
-int __init dom0_construct_pvh(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline)
+int __init dom0_construct_pvh(struct boot_domain *bd)
 {
+    struct domain *d = bd->domain;
     paddr_t entry, start_info;
     int rc;
 
@@ -1249,8 +1249,8 @@  int __init dom0_construct_pvh(
         return rc;
     }
 
-    rc = pvh_load_kernel(d, image, initrd, bootstrap_map(image),
-                         cmdline, &entry, &start_info);
+    rc = pvh_load_kernel(d, bd->kernel, bd->ramdisk, bootstrap_map(bd->kernel),
+                         bd->kernel->string.bytes, &entry, &start_info);
     if ( rc )
     {
         printk("Failed to load Dom0 kernel\n");
diff --git a/xen/arch/x86/include/asm/dom0_build.h b/xen/arch/x86/include/asm/dom0_build.h
index ad33413710..571b25ea71 100644
--- a/xen/arch/x86/include/asm/dom0_build.h
+++ b/xen/arch/x86/include/asm/dom0_build.h
@@ -14,13 +14,9 @@  unsigned long dom0_compute_nr_pages(struct domain *d,
                                     unsigned long initrd_len);
 int dom0_setup_permissions(struct domain *d);
 
-int __init dom0_construct_pv(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline);
+int dom0_construct_pv(struct boot_domain *bd);
 
-int __init dom0_construct_pvh(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline);
+int dom0_construct_pvh(struct boot_domain *bd);
 
 unsigned long dom0_paging_pages(const struct domain *d,
                                 unsigned long nr_pages);
diff --git a/xen/arch/x86/include/asm/setup.h b/xen/arch/x86/include/asm/setup.h
index 27c0d61819..f9c1468fcc 100644
--- a/xen/arch/x86/include/asm/setup.h
+++ b/xen/arch/x86/include/asm/setup.h
@@ -33,9 +33,8 @@  void vesa_init(void);
 static inline void vesa_init(void) {};
 #endif
 
-int construct_dom0(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline);
+int construct_domain(struct boot_domain *bd);
+
 void setup_io_bitmap(struct domain *d);
 
 unsigned long initial_images_nrpages(nodeid_t node);
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index f6131147ef..78ebb03b1b 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -4,6 +4,7 @@ 
  * Copyright (c) 2002-2005, K A Fraser
  */
 
+#include <xen/bootdomain.h>
 #include <xen/bootinfo.h>
 #include <xen/console.h>
 #include <xen/domain.h>
@@ -295,9 +296,7 @@  static struct page_info * __init alloc_chunk(struct domain *d,
     return page;
 }
 
-int __init dom0_construct_pv(
-    struct domain *d, const struct boot_module *image,
-    struct boot_module *initrd, char *cmdline)
+int __init dom0_construct_pv(struct boot_domain *bd)
 {
     int i, rc, order, machine;
     bool compatible, compat;
@@ -311,11 +310,12 @@  int __init dom0_construct_pv(
     unsigned long count;
     struct page_info *page = NULL;
     start_info_t *si;
+    struct domain *d = bd->domain;
     struct vcpu *v = d->vcpu[0];
-    void *image_base = bootstrap_map(image);
-    unsigned long image_len = image->size;
-    void *image_start = image_base + image->arch->headroom;
-    unsigned long initrd_len = initrd ? initrd->size : 0;
+    void *image_base = bootstrap_map(bd->kernel);
+    unsigned long image_len = bd->kernel->size;
+    void *image_start = image_base + bd->kernel->arch->headroom;
+    unsigned long initrd_len = bd->ramdisk ? bd->ramdisk->size : 0;
     l4_pgentry_t *l4tab = NULL, *l4start = NULL;
     l3_pgentry_t *l3tab = NULL, *l3start = NULL;
     l2_pgentry_t *l2tab = NULL, *l2start = NULL;
@@ -355,7 +355,7 @@  int __init dom0_construct_pv(
     d->max_pages = ~0U;
 
     if ( (rc =
-          bzimage_parse(image_base, &image_start, image->arch->headroom,
+          bzimage_parse(image_base, &image_start, bd->kernel->arch->headroom,
                          &image_len)) != 0 )
         return rc;
 
@@ -545,7 +545,7 @@  int __init dom0_construct_pv(
         initrd_pfn = vinitrd_start ?
                      (vinitrd_start - v_start) >> PAGE_SHIFT :
                      domain_tot_pages(d);
-        initrd_mfn = mfn = mfn_x(initrd->mfn);
+        initrd_mfn = mfn = mfn_x(bd->ramdisk->mfn);
         count = PFN_UP(initrd_len);
         if ( d->arch.physaddr_bitsize &&
              ((mfn + count - 1) >> (d->arch.physaddr_bitsize - PAGE_SHIFT)) )
@@ -560,13 +560,13 @@  int __init dom0_construct_pv(
                     free_domheap_pages(page, order);
                     page += 1UL << order;
                 }
-            memcpy(page_to_virt(page), maddr_to_virt(initrd->start),
+            memcpy(page_to_virt(page), maddr_to_virt(bd->ramdisk->start),
                    initrd_len);
-            mpt_alloc = initrd->start;
+            mpt_alloc = bd->ramdisk->start;
             init_domheap_pages(mpt_alloc,
                                mpt_alloc + PAGE_ALIGN(initrd_len));
-            bootmodule_update_mfn(initrd, page_to_mfn(page));
-            initrd_mfn = mfn_x(initrd->mfn);
+            bootmodule_update_mfn(bd->ramdisk, page_to_mfn(page));
+            initrd_mfn = mfn_x(bd->ramdisk->mfn);
         }
         else
         {
@@ -574,7 +574,7 @@  int __init dom0_construct_pv(
                 if ( assign_pages(mfn_to_page(_mfn(mfn++)), 1, d, 0) )
                     BUG();
         }
-        initrd->size = 0;
+        bd->ramdisk->size = 0;
     }
 
     printk("PHYSICAL MEMORY ARRANGEMENT:\n"
@@ -583,9 +583,9 @@  int __init dom0_construct_pv(
     if ( domain_tot_pages(d) < nr_pages )
         printk(" (%lu pages to be allocated)",
                nr_pages - domain_tot_pages(d));
-    if ( initrd )
+    if ( bd->ramdisk )
     {
-        mpt_alloc = initrd->start;
+        mpt_alloc = bd->ramdisk->start;
         printk("\n Init. ramdisk: %"PRIpaddr"->%"PRIpaddr,
                mpt_alloc, mpt_alloc + initrd_len);
     }
@@ -806,7 +806,7 @@  int __init dom0_construct_pv(
         if ( pfn >= initrd_pfn )
         {
             if ( pfn < initrd_pfn + PFN_UP(initrd_len) )
-                mfn = mfn_x(initrd->mfn) + (pfn - initrd_pfn);
+                mfn = mfn_x(bd->ramdisk->mfn) + (pfn - initrd_pfn);
             else
                 mfn -= PFN_UP(initrd_len);
         }
@@ -866,8 +866,9 @@  int __init dom0_construct_pv(
     }
 
     memset(si->cmd_line, 0, sizeof(si->cmd_line));
-    if ( cmdline != NULL )
-        strlcpy((char *)si->cmd_line, cmdline, sizeof(si->cmd_line));
+    if ( strlen(bd->kernel->string.bytes) > 0 )
+        strlcpy((char *)si->cmd_line, bd->kernel->string.bytes,
+                sizeof(si->cmd_line));
 
 #ifdef CONFIG_VIDEO
     if ( !pv_shim && fill_console_start_info((void *)(si + 1)) )
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 28dbfcd209..860b9e3d64 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -45,7 +45,6 @@ 
 #include <asm/edd.h>
 #include <xsm/xsm.h>
 #include <asm/tboot.h>
-#include <asm/bzimage.h> /* for bzimage_headroom */
 #include <asm/mach-generic/mach_apic.h> /* for generic_apic_probe */
 #include <asm/setup.h>
 #include <xen/cpu.h>
@@ -272,6 +271,24 @@  static int __init cf_check parse_acpi_param(const char *s)
 }
 custom_param("acpi", parse_acpi_param);
 
+void __init arch_builder_apply_cmdline(
+    struct boot_info *info, struct boot_domain *bd)
+{
+    if ( skip_ioapic_setup && !strstr(bd->kernel->string.bytes, "noapic") )
+        strlcat(bd->kernel->string.bytes, " noapic", MAX_GUEST_CMDLINE);
+    if ( (strlen(acpi_param) == 0) && acpi_disabled )
+    {
+        printk("ACPI is disabled, notifying Domain 0 (acpi=off)\n");
+        strlcpy(acpi_param, "off", sizeof(acpi_param));
+    }
+    if ( (strlen(acpi_param) != 0) &&
+         !strstr(bd->kernel->string.bytes, "acpi=") )
+    {
+        strlcat(bd->kernel->string.bytes, " acpi=", MAX_GUEST_CMDLINE);
+        strlcat(bd->kernel->string.bytes, acpi_param, MAX_GUEST_CMDLINE);
+    }
+}
+
 struct boot_info __initdata *boot_info;
 
 unsigned long __init initial_images_nrpages(nodeid_t node)
@@ -728,7 +745,8 @@  static unsigned int __init copy_bios_e820(struct e820entry *map, unsigned int li
     return n;
 }
 
-static struct domain *__init create_dom0(const struct boot_info *bi)
+static struct domain *__init create_dom0(
+    const struct boot_info *bi, struct boot_domain *bd)
 {
     struct xen_domctl_createdomain dom0_cfg = {
         .flags = IS_ENABLED(CONFIG_TBOOT) ? XEN_DOMCTL_CDF_s3_integrity : 0,
@@ -741,14 +759,10 @@  static struct domain *__init create_dom0(const struct boot_info *bi)
             .misc_flags = opt_dom0_msr_relaxed ? XEN_X86_MSR_RELAXED : 0,
         },
     };
-    struct boot_module *image = bootmodule_next_by_kind(bi, BOOTMOD_KERNEL, 0);
-    struct boot_module *initrd = bootmodule_next_by_kind(bi, BOOTMOD_RAMDISK, 0);
-    struct domain *d;
     char *cmdline;
-    domid_t domid = 0;
 
-    if ( image == NULL )
-        panic("Error creating d%uv0\n", domid);
+    if ( bd->kernel == NULL )
+        panic("Error creating d%uv0\n", bd->domid);
 
     if ( opt_dom0_pvh )
     {
@@ -764,45 +778,46 @@  static struct domain *__init create_dom0(const struct boot_info *bi)
         dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
 
     /* Create initial domain.  Not d0 for pvshim. */
-    domid = get_initial_domain_id();
-    d = domain_create(domid, &dom0_cfg, pv_shim ? 0 : CDF_privileged);
-    if ( IS_ERR(d) )
-        panic("Error creating d%u: %ld\n", domid, PTR_ERR(d));
+    bd->domid = get_initial_domain_id();
+    bd->domain = domain_create(bd->domid, &dom0_cfg, pv_shim ?
+                               0 : CDF_privileged);
+    if ( IS_ERR(bd->domain) )
+        panic("Error creating d%u: %ld\n", bd->domid, PTR_ERR(bd->domain));
 
-    init_dom0_cpuid_policy(d);
+    init_dom0_cpuid_policy(bd->domain);
 
-    if ( alloc_dom0_vcpu0(d) == NULL )
-        panic("Error creating d%uv0\n", domid);
+    if ( alloc_dom0_vcpu0(bd->domain) == NULL )
+        panic("Error creating d%uv0\n", bd->domid);
 
     /* Grab the DOM0 command line. */
-    cmdline = (image->string.kind == BOOTSTR_CMDLINE) ?
-              image->string.bytes : NULL;
+    cmdline = (bd->kernel->string.kind == BOOTSTR_CMDLINE) ?
+              bd->kernel->string.bytes : NULL;
     if ( cmdline || bi->arch->kextra )
     {
-        static char __initdata dom0_cmdline[MAX_GUEST_CMDLINE];
+        char dom0_cmdline[MAX_GUEST_CMDLINE];
 
         cmdline = arch_prepare_cmdline(cmdline, bi->arch);
-        safe_strcpy(dom0_cmdline, cmdline);
+        strlcpy(dom0_cmdline, cmdline, MAX_GUEST_CMDLINE);
 
         if ( bi->arch->kextra )
             /* kextra always includes exactly one leading space. */
-            safe_strcat(dom0_cmdline, bi->arch->kextra);
+            strlcat(dom0_cmdline, bi->arch->kextra, MAX_GUEST_CMDLINE);
 
         /* Append any extra parameters. */
         if ( skip_ioapic_setup && !strstr(dom0_cmdline, "noapic") )
-            safe_strcat(dom0_cmdline, " noapic");
+            strlcat(dom0_cmdline, " noapic", MAX_GUEST_CMDLINE);
         if ( (strlen(acpi_param) == 0) && acpi_disabled )
         {
             printk("ACPI is disabled, notifying Domain 0 (acpi=off)\n");
-            safe_strcpy(acpi_param, "off");
+            strlcpy(acpi_param, "off", sizeof(acpi_param));
         }
         if ( (strlen(acpi_param) != 0) && !strstr(dom0_cmdline, "acpi=") )
         {
-            safe_strcat(dom0_cmdline, " acpi=");
-            safe_strcat(dom0_cmdline, acpi_param);
+            strlcat(dom0_cmdline, " acpi=", MAX_GUEST_CMDLINE);
+            strlcat(dom0_cmdline, acpi_param, MAX_GUEST_CMDLINE);
         }
 
-        cmdline = dom0_cmdline;
+        strlcpy(bd->kernel->string.bytes, dom0_cmdline, MAX_GUEST_CMDLINE);
     }
 
     /*
@@ -816,7 +831,7 @@  static struct domain *__init create_dom0(const struct boot_info *bi)
         write_cr4(read_cr4() & ~X86_CR4_SMAP);
     }
 
-    if ( construct_dom0(d, image, initrd, cmdline) != 0 )
+    if ( construct_domain(bd) != 0 )
         panic("Could not construct domain 0\n");
 
     if ( cpu_has_smap )
@@ -825,14 +840,14 @@  static struct domain *__init create_dom0(const struct boot_info *bi)
         cr4_pv32_mask |= X86_CR4_SMAP;
     }
 
-    return d;
+    return bd->domain;
 }
 
 void __init arch_create_dom(
     const struct boot_info *bi, struct boot_domain *bd)
 {
     if ( builder_is_initdom(bd) )
-        create_dom0(bi);
+        create_dom0(bi, bd);
 }
 
 /* How much of the directmap is prebuilt at compile time. */
@@ -1010,10 +1025,7 @@  void __init noreturn __start_xen(unsigned long bi_p)
                boot_info->nr_mods);
     }
 
-    /* Dom0 kernel is the first boot module */
-    boot_info->mods[0].kind = BOOTMOD_KERNEL;
-    if ( boot_info->mods[0].string.len )
-        boot_info->mods[0].string.kind = BOOTSTR_CMDLINE;
+    builder_init(boot_info);
 
     if ( pvh_boot )
     {
@@ -1168,11 +1180,6 @@  void __init noreturn __start_xen(unsigned long bi_p)
         boot_info->mods[boot_info->nr_mods].size = __2M_rwdata_end - _stext;
     }
 
-    boot_info->mods[0].arch->headroom = bzimage_headroom(
-                                        bootstrap_map(&boot_info->mods[0]),
-                                        boot_info->mods[0].size);
-    bootstrap_map(NULL);
-
 #ifndef highmem_start
     /* Don't allow split below 4Gb. */
     if ( highmem_start < GB(4) )
@@ -1905,22 +1912,29 @@  void __init noreturn __start_xen(unsigned long bi_p)
            cpu_has_nx ? XENLOG_INFO : XENLOG_WARNING "Warning: ",
            cpu_has_nx ? "" : "not ");
 
-    initrdidx = bootmodule_next_idx_by_kind(boot_info, BOOTMOD_UNKNOWN, 0);
-    if ( initrdidx < boot_info->nr_mods )
-        boot_info->mods[initrdidx].kind = BOOTMOD_RAMDISK;
-
-    if ( bootmodule_count_by_kind(boot_info, BOOTMOD_UNKNOWN) > 1 )
-        printk(XENLOG_WARNING
-               "Multiple initrd candidates, picking module #%u\n",
-               initrdidx);
-
     /*
-     * We're going to setup domain0 using the module(s) that we stashed safely
-     * above our heap. The second module, if present, is an initrd ramdisk.
+     * Boot description not provided, check to see if there are any remaining
+     * boot modules, the first one found will be provided as the ramdisk.
      */
-    dom0 = create_dom0(boot_info);
+    if ( ! boot_info->builder->fdt_enabled )
+    {
+        initrdidx = bootmodule_next_idx_by_kind(boot_info, BOOTMOD_UNKNOWN, 0);
+        if ( initrdidx < boot_info->nr_mods )
+        {
+            boot_info->builder->domains[0].ramdisk = &boot_info->mods[initrdidx];
+            boot_info->mods[initrdidx].kind = BOOTMOD_RAMDISK;
+        }
+        if ( bootmodule_count_by_kind(boot_info, BOOTMOD_UNKNOWN) > 1 )
+            printk(XENLOG_WARNING
+                   "Multiple initrd candidates, picking module #%u\n",
+                   initrdidx);
+    }
+
+    builder_create_domains(boot_info);
+
+    dom0 = builder_get_hwdom(boot_info);
     if ( !dom0 )
-        panic("Could not set up DOM0 guest OS\n");
+        panic("No hardware domain was built\n");
 
     heap_init_late();