[Xen-devel] [PATCH v6 08/14] hvmloader: Locate the BIOS blob

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

The BIOS blob can be found an entry called "firmware" of the modlist of
the hvm_start_info struct.

The found BIOS blob is not loaded by this patch, but only passed as
argument to bios_load() function.

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

---
Changes in V6:
- cast addresses to uintptr_t instead of uint32_t.
- use UINTPTR_MAX for the upper boundary checks.
- Do a full check of every things that are used, check that modlist,
  cmdlines, modules lives below 4GB and does not cross the boundary.

Changes in V5:
- don't BUG() on module's paddr having value 0, and just skip.
- fix some coding style
- rename module name to "firmware" (was "bios")
- less use of BUG_ON in get_module_entry() and skip entries instead.
  Only BUG() if the module which match name is not accessible.

Changes in V4:
- add more BUG_ON into get_module_entry(). Check that modules paddr and
  size are 32bits.

Changes in V3:
- fix some codying style
- use module.cmdline to look for a module name instead of the main cmdline
  from hvm_start_info.
---
 tools/firmware/hvmloader/config.h    |  2 +-
 tools/firmware/hvmloader/hvmloader.c | 60 ++++++++++++++++++++++++++++++++++--
 tools/firmware/hvmloader/ovmf.c      |  3 +-
 tools/firmware/hvmloader/rombios.c   |  3 +-
 4 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/tools/firmware/hvmloader/config.h 
b/tools/firmware/hvmloader/config.h
index b838cf9..4c6d8ad 100644
--- a/tools/firmware/hvmloader/config.h
+++ b/tools/firmware/hvmloader/config.h
@@ -22,7 +22,7 @@ struct bios_config {
     /* ROMS */
     void (*load_roms)(void);
 
-    void (*bios_load)(const struct bios_config *config);
+    void (*bios_load)(const struct bios_config *config, void *addr, uint32_t 
size);
 
     void (*bios_info_setup)(void);
     void (*bios_info_finish)(void);
diff --git a/tools/firmware/hvmloader/hvmloader.c 
b/tools/firmware/hvmloader/hvmloader.c
index 77c70e0..5c57ab3 100644
--- a/tools/firmware/hvmloader/hvmloader.c
+++ b/tools/firmware/hvmloader/hvmloader.c
@@ -254,10 +254,57 @@ static void acpi_enable_sci(void)
     BUG_ON(!(pm1a_cnt_val & ACPI_PM1C_SCI_EN));
 }
 
+const struct hvm_modlist_entry *get_module_entry(
+    const struct hvm_start_info *info,
+    const char *name)
+{
+    const struct hvm_modlist_entry *modlist =
+        (struct hvm_modlist_entry *)(uintptr_t)info->modlist_paddr;
+    unsigned int i;
+
+    if ( !modlist ||
+         info->modlist_paddr > UINTPTR_MAX ||
+         (info->modlist_paddr + info->nr_modules * sizeof(*modlist) - 1)
+            > UINTPTR_MAX
+         )
+        return NULL;
+
+    for ( i = 0; i < info->nr_modules; i++ )
+    {
+        char *module_name = (char*)(uintptr_t)modlist[i].cmdline_paddr;
+
+        /* Skip if the module or its cmdline is missing. */
+        if ( !module_name || !modlist[i].paddr )
+            continue;
+
+        /* Skip if the cmdline can not be read. */
+        if ( modlist[i].cmdline_paddr > UINTPTR_MAX ||
+             (modlist[i].cmdline_paddr + strlen(name)) > UINTPTR_MAX )
+            continue;
+
+        if ( !strcmp(name, module_name) )
+        {
+            if ( modlist[i].paddr > UINTPTR_MAX ||
+                 modlist[i].size > UINTPTR_MAX ||
+                 (modlist[i].paddr + modlist[i].size - 1) > UINTPTR_MAX )
+            {
+                printf("Can not load \"%s\" from 0x"PRIllx" (0x"PRIllx")\n",
+                       name, PRIllx_arg(modlist[i].paddr),
+                       PRIllx_arg(modlist[i].size));
+                BUG();
+            }
+            return &modlist[i];
+        }
+    }
+
+    return NULL;
+}
+
 int main(void)
 {
     const struct bios_config *bios;
     int acpi_enabled;
+    const struct hvm_modlist_entry *bios_module;
 
     /* Initialise hypercall stubs with RET, rendering them no-ops. */
     memset((void *)HYPERCALL_PHYSICAL_ADDRESS, 0xc3 /* RET */, PAGE_SIZE);
@@ -293,8 +340,17 @@ int main(void)
     }
 
     printf("Loading %s ...\n", bios->name);
-    if ( bios->bios_load )
-        bios->bios_load(bios);
+    bios_module = get_module_entry(hvm_start_info, "firmware");
+    if ( bios_module && bios->bios_load )
+    {
+        uint32_t paddr = bios_module->paddr;
+
+        bios->bios_load(bios, (void*)paddr, bios_module->size);
+    }
+    else if ( bios->bios_load )
+    {
+        bios->bios_load(bios, NULL, 0);
+    }
     else
     {
         BUG_ON(bios->bios_address + bios->image_size >
diff --git a/tools/firmware/hvmloader/ovmf.c b/tools/firmware/hvmloader/ovmf.c
index db9fa7a..858a2d4 100644
--- a/tools/firmware/hvmloader/ovmf.c
+++ b/tools/firmware/hvmloader/ovmf.c
@@ -93,7 +93,8 @@ static void ovmf_finish_bios_info(void)
     info->checksum = -checksum;
 }
 
-static void ovmf_load(const struct bios_config *config)
+static void ovmf_load(const struct bios_config *config,
+                      void *bios_addr, uint32_t bios_length)
 {
     xen_pfn_t mfn;
     uint64_t addr = OVMF_BEGIN;
diff --git a/tools/firmware/hvmloader/rombios.c 
b/tools/firmware/hvmloader/rombios.c
index 1f15b94..2ded844 100644
--- a/tools/firmware/hvmloader/rombios.c
+++ b/tools/firmware/hvmloader/rombios.c
@@ -121,7 +121,8 @@ static void rombios_load_roms(void)
                option_rom_phys_addr + option_rom_sz - 1);
 }
 
-static void rombios_load(const struct bios_config *config)
+static void rombios_load(const struct bios_config *config,
+                         void *unused_addr, uint32_t unused_size)
 {
     uint32_t bioshigh;
     struct rombios_info *info;
-- 
Anthony PERARD


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