[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[PATCH v2 2/2] arm/efi: Use dom0less configuration when using EFI boot



This patch introduces the support for dom0less configuration
when using UEFI boot on ARM, it permits the EFI boot to
continue if no dom0 kernel is specified but at least one domU
is found.

Introduce the new property "uefi,binary" for device tree boot
module nodes that are subnode of "xen,domain" compatible nodes.
The property holds a string containing the file name of the
binary that shall be loaded by the uefi loader from the filesystem.

Update efi documentation about how to start a dom0less
setup using UEFI

Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
Changes in v2:
- remove array of struct file
- fixed some int types
- Made the code use filesystem even when configuration
file is skipped.
- add documentation of uefi,binary in booting.txt
- add documentation on how to boot all configuration
for Xen using UEFI in efi.pandoc
---
 docs/misc/arm/device-tree/booting.txt |  21 +++
 docs/misc/efi.pandoc                  | 203 ++++++++++++++++++++
 xen/arch/arm/efi/efi-boot.h           | 257 +++++++++++++++++++++++++-
 xen/arch/x86/efi/efi-boot.h           |   6 +
 xen/common/efi/boot.c                 |  36 ++--
 5 files changed, 508 insertions(+), 15 deletions(-)

diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
index 44cd9e1a9a..bc0f8913db 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -182,6 +182,13 @@ The kernel sub-node has the following properties:
 
     Command line parameters for the guest kernel.
 
+- efi,binary (UEFI boot only)
+
+    Specifies the file name to be loaded by the UEFI boot for this module. If
+    this is specified, there is no need to specify the reg property because it
+    will be created by the UEFI stub on boot.
+    This option is needed only when UEFI boot is used.
+
 The ramdisk sub-node has the following properties:
 
 - compatible
@@ -193,6 +200,13 @@ The ramdisk sub-node has the following properties:
     Specifies the physical address of the ramdisk in RAM and its
     length.
 
+- efi,binary (UEFI boot only)
+
+    Specifies the file name to be loaded by the UEFI boot for this module. If
+    this is specified, there is no need to specify the reg property because it
+    will be created by the UEFI stub on boot.
+    This option is needed only when UEFI boot is used.
+
 
 Example
 =======
@@ -257,6 +271,13 @@ The dtb sub-node should have the following properties:
     Specifies the physical address of the device tree binary fragment
     RAM and its length.
 
+- efi,binary (UEFI boot only)
+
+    Specifies the file name to be loaded by the UEFI boot for this module. If
+    this is specified, there is no need to specify the reg property because it
+    will be created by the UEFI stub on boot.
+    This option is needed only when UEFI boot is used.
+
 As an example:
 
         module@0xc000000 {
diff --git a/docs/misc/efi.pandoc b/docs/misc/efi.pandoc
index e289c5e7ba..698196e129 100644
--- a/docs/misc/efi.pandoc
+++ b/docs/misc/efi.pandoc
@@ -167,3 +167,206 @@ sbsign \
        --output xen.signed.efi \
        xen.unified.efi
 ```
+
+## UEFI boot and dom0less on ARM
+
+Dom0less feature is supported by ARM and it is possible to use it when Xen is
+started as an EFI application.
+The way to specify the domU domains is by Device Tree as specified in the
+[dom0less](dom0less.html) documentation page under the "Device Tree
+configuration" section, but instead of declaring the reg property in the boot
+module, the user must specify the "uefi,binary" property containing the name
+of the binary file that has to be loaded in memory.
+The UEFI stub will load the binary in memory and it will add the reg property
+accordingly.
+
+An example here:
+
+domU1 {
+       #address-cells = <1>;
+       #size-cells = <1>;
+       compatible = "xen,domain";
+       memory = <0 0x20000>;
+       cpus = <1>;
+       vpl011;
+
+       module@1 {
+               compatible = "multiboot,kernel", "multiboot,module";
+               uefi,binary = "vmlinuz-3.0.31-0.4-xen";
+               bootargs = "console=ttyAMA0";
+       };
+       module@2 {
+               compatible = "multiboot,ramdisk", "multiboot,module";
+               uefi,binary = "initrd-3.0.31-0.4-xen";
+       };
+       module@3 {
+               compatible = "multiboot,ramdisk", "multiboot,module";
+               uefi,binary = "passthrough.dtb";
+       };
+};
+
+## How to boot different Xen setup using UEFI
+
+Here the supported user cases for Xen when UEFI boot is used:
+
+ - Boot Xen and Dom0 (minimum required)
+ - Boot Xen and DomU(s) (true dom0less, only on ARM)
+ - Boot Xen, Dom0 and DomU(s) (only on ARM)
+
+### Boot Xen and Dom0
+
+This configuration can be started using the Xen configuration file in the
+example above.
+
+### Boot Xen and DomU(s)
+
+This configuration needs the domU domain(s) specified in the /chosen node,
+examples of how to do that are provided by the documentation about dom0less
+and the example above shows how to use the "uefi,binary" property to use the
+UEFI stub for module loading.
+Providing the multiboot modules in the device tree, make Xen skip its UEFI
+configuration file, if it is needed for some reason, specify the 
"uefi,cfg-load"
+property in the /chosen node.
+
+Example 1 of how to boot a true dom0less configuration:
+
+Xen configuration file: skipped.
+
+Device tree:
+
+```
+chosen {
+       #size-cells = <0x1>;
+       #address-cells = <0x1>;
+       xen,xen-bootargs = "<Xen command line>"
+
+       domU1 {
+               #size-cells = <0x1>;
+               #address-cells = <0x1>;
+               compatible = "xen,domain";
+               cpus = <0x1>;
+               memory = <0x0 0xc0000>;
+               vpl011;
+
+               module@1 {
+                       compatible = "multiboot,kernel", "multiboot,module";
+                       uefi,binary = "Image-domu1.bin";
+                       bootargs = "console=ttyAMA0 root=/dev/ram0 rw";
+               };
+       };
+       domU2 {
+               #size-cells = <0x1>;
+               #address-cells = <0x1>;
+               compatible = "xen,domain";
+               cpus = <0x1>;
+               memory = <0x0 0x100000>;
+               vpl011;
+
+               module@2 {
+                       compatible = "multiboot,kernel", "multiboot,module";
+                       uefi,binary = "Image-domu2.bin";
+                       bootargs = "console=ttyAMA0 root=/dev/ram0 rw";
+               };
+       };
+};
+```
+
+Example 2 of how to boot a true dom0less configuration:
+
+Xen configuration file:
+
+```
+[global]
+default=xen
+
+[xen]
+options=<Xen command line>
+dtb=<optional DTB>
+```
+
+Device tree:
+
+```
+chosen {
+       #size-cells = <0x1>;
+       #address-cells = <0x1>;
+       uefi,cfg-load;
+
+       domU1 {
+               #size-cells = <0x1>;
+               #address-cells = <0x1>;
+               compatible = "xen,domain";
+               cpus = <0x1>;
+               memory = <0x0 0xc0000>;
+               vpl011;
+
+               module@1 {
+                       compatible = "multiboot,kernel", "multiboot,module";
+                       uefi,binary = "Image-domu1.bin";
+                       bootargs = "console=ttyAMA0 root=/dev/ram0 rw";
+               };
+       };
+       domU2 {
+               #size-cells = <0x1>;
+               #address-cells = <0x1>;
+               compatible = "xen,domain";
+               cpus = <0x1>;
+               memory = <0x0 0x100000>;
+               vpl011;
+
+               module@2 {
+                       compatible = "multiboot,kernel", "multiboot,module";
+                       uefi,binary = "Image-domu2.bin";
+                       bootargs = "console=ttyAMA0 root=/dev/ram0 rw";
+               };
+       };
+};
+```
+
+### Boot Xen, Dom0 and DomU(s)
+
+This configuration is a mix of the two configuration above, to boot this one
+the configuration file must be processed so the /chosen node must have the
+"uefi,cfg-load" property.
+
+Here an example:
+
+Xen configuration file:
+
+```
+[global]
+default=xen
+
+[xen]
+options=<Xen command line>
+kernel=vmlinuz-3.0.31-0.4-xen [domain 0 command line options]
+ramdisk=initrd-3.0.31-0.4-xen
+dtb=<optional DTB>
+```
+
+Device tree:
+
+```
+chosen {
+       #size-cells = <0x1>;
+       #address-cells = <0x1>;
+       uefi,cfg-load;
+
+       domU1 {
+               #size-cells = <0x1>;
+               #address-cells = <0x1>;
+               compatible = "xen,domain";
+               cpus = <0x1>;
+               memory = <0x0 0xc0000>;
+               vpl011;
+
+               module@1 {
+                       compatible = "multiboot,kernel", "multiboot,module";
+                       uefi,binary = "Image-domu1.bin";
+                       bootargs = "console=ttyAMA0 root=/dev/ram0 rw";
+               };
+       };
+};
+```
+
+
diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 8ceeba4ad1..e2b007ece0 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -8,9 +8,43 @@
 #include <asm/setup.h>
 #include <asm/smp.h>
 
+typedef struct {
+    char *name;
+    unsigned int name_len;
+    EFI_PHYSICAL_ADDRESS addr;
+    UINTN size;
+} dom0less_module_name;
+
+/*
+ * Binaries will be translated into bootmodules, the maximum number for them is
+ * MAX_MODULES where we should remove a unit for Xen and one for Xen DTB
+ */
+#define MAX_DOM0LESS_MODULES (MAX_MODULES - 2)
+static struct file __initdata dom0less_file;
+static dom0less_module_name __initdata dom0less_modules[MAX_DOM0LESS_MODULES];
+static unsigned int __initdata dom0less_modules_available =
+                               MAX_DOM0LESS_MODULES;
+static unsigned int __initdata dom0less_modules_idx;
+
+#define ERROR_DOM0LESS_FILE_NOT_FOUND (-1)
+
 void noreturn efi_xen_start(void *fdt_ptr, uint32_t fdt_size);
 void __flush_dcache_area(const void *vaddr, unsigned long size);
 
+static int get_dom0less_file_index(const char *name, unsigned int name_len);
+static unsigned int allocate_dom0less_file(EFI_FILE_HANDLE dir_handle,
+                                           const char *name,
+                                           unsigned int name_len);
+static void handle_dom0less_module_node(EFI_FILE_HANDLE dir_handle,
+                                        int module_node_offset,
+                                        int reg_addr_cells,
+                                        int reg_size_cells);
+static void handle_dom0less_domain_node(EFI_FILE_HANDLE dir_handle,
+                                        int domain_node,
+                                        int addr_cells,
+                                        int size_cells);
+static bool efi_arch_check_dom0less_boot(EFI_FILE_HANDLE dir_handle);
+
 #define DEVICE_TREE_GUID \
 {0xb1b621d5, 0xf19c, 0x41a5, {0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0}}
 
@@ -552,8 +586,218 @@ static void __init efi_arch_handle_module(const struct 
file *file,
                          kernel.size) < 0 )
             blexit(L"Unable to set reg property.");
     }
-    else
+    else if ( file != &dom0less_file )
+        /*
+         * If file is not a dom0 module file and it's not a domU module,
+         * stop here.
+         */
         blexit(L"Unknown module type");
+
+    /*
+     * dom0less_modules_available is decremented here because for each dom0
+     * file added, there will be an additional bootmodule, so the number
+     * of dom0less module files will be decremented because there is
+     * a maximum amount of bootmodules that can be loaded.
+     */
+    dom0less_modules_available--;
+}
+
+/*
+ * This function checks for a binary previously loaded with a give name, it
+ * returns the index of the file in the dom0less_files array or a negative
+ * number if no file with that name is found.
+ */
+static int __init get_dom0less_file_index(const char *name,
+                                          unsigned int name_len)
+{
+    unsigned int i;
+    int ret = ERROR_DOM0LESS_FILE_NOT_FOUND;
+
+    for (i = 0; i < dom0less_modules_idx; i++)
+    {
+        dom0less_module_name *mod = &dom0less_modules[i];
+        if ( (mod->name_len == name_len) &&
+             (strncmp(mod->name, name, name_len) == 0) )
+        {
+            ret = i;
+            break;
+        }
+    }
+    return ret;
+}
+
+/*
+ * This function allocates a binary and keeps track of its name, it
+ * returns the index of the file in the dom0less_files array.
+ */
+static unsigned int __init allocate_dom0less_file(EFI_FILE_HANDLE dir_handle,
+                                                  const char *name,
+                                                  unsigned int name_len)
+{
+    dom0less_module_name* file_name;
+    union string module_name;
+    unsigned int ret_idx;
+
+    /*
+     * Check if there is any space left for a domU module, the variable
+     * dom0less_modules_available is updated each time we use read_file(...)
+     * successfully.
+     */
+    if ( !dom0less_modules_available )
+        blexit(L"No space left for domU modules");
+
+    module_name.s = (char*) name;
+    ret_idx = dom0less_modules_idx;
+
+    /* Save at this index the name of this binary */
+    file_name = &dom0less_modules[ret_idx];
+
+    if ( efi_bs->AllocatePool(EfiLoaderData, (name_len + 1) * sizeof(char),
+                              (void**)&file_name->name) != EFI_SUCCESS )
+        blexit(L"Error allocating memory for dom0less binary name");
+
+    /* Save name and length of the binary in the data structure */
+    strlcpy(file_name->name, name, name_len);
+    file_name->name_len = name_len;
+
+    /* Load the binary in memory */
+    read_file(dir_handle, s2w(&module_name), &dom0less_file, NULL);
+
+    /* Save address and size */
+    file_name->addr = dom0less_file.addr;
+    file_name->size = dom0less_file.size;
+
+    /* s2w(...) allocates some memory, free it */
+    efi_bs->FreePool(module_name.w);
+
+    dom0less_modules_idx++;
+
+    return ret_idx;
+}
+
+/*
+ * This function checks for the presence of the uefi,binary property in the
+ * module, if found it loads the binary as dom0less module and sets the right
+ * address for the reg property into the module DT node.
+ */
+static void __init handle_dom0less_module_node(EFI_FILE_HANDLE dir_handle,
+                                          int module_node_offset,
+                                          int reg_addr_cells,
+                                          int reg_size_cells)
+{
+    const void *uefi_name_prop;
+    char mod_string[24]; /* Placeholder for module@ + a 64-bit number + \0 */
+    int uefi_name_len, file_idx;
+    dom0less_module_name *file;
+
+    /* Read uefi,binary property to get the file name. */
+    uefi_name_prop = fdt_getprop(fdt, module_node_offset, "uefi,binary",
+                                 &uefi_name_len);
+
+    if ( !uefi_name_prop )
+        /* Property not found */
+        return;
+
+    file_idx = get_dom0less_file_index(uefi_name_prop, uefi_name_len);
+    if (file_idx < 0)
+        file_idx = allocate_dom0less_file(dir_handle, uefi_name_prop,
+                                          uefi_name_len);
+
+    file = &dom0less_modules[file_idx];
+
+    snprintf(mod_string, sizeof(mod_string), "module@%"PRIx64, file->addr);
+
+    /* Rename the module to be module@{address} */
+    if ( fdt_set_name(fdt, module_node_offset, mod_string) < 0 )
+        blexit(L"Unable to add domU ramdisk FDT node.");
+
+    if ( fdt_set_reg(fdt, module_node_offset, reg_addr_cells, reg_size_cells,
+                     file->addr, file->size) < 0 )
+        blexit(L"Unable to set reg property.");
+}
+
+/*
+ * This function checks for boot modules under the domU guest domain node
+ * in the DT.
+ */
+static void __init handle_dom0less_domain_node(EFI_FILE_HANDLE dir_handle,
+                                               int domain_node,
+                                               int addr_cells,
+                                               int size_cells)
+{
+    int module_node;
+    /*
+     * Check for nodes compatible with multiboot,{kernel,ramdisk,device-tree}
+     * inside this node
+     */
+    for ( module_node = fdt_first_subnode(fdt, domain_node);
+          module_node > 0;
+          module_node = fdt_next_subnode(fdt, module_node) )
+        if ( (fdt_node_check_compatible(fdt, module_node,
+                                        "multiboot,kernel") == 0) ||
+             (fdt_node_check_compatible(fdt, module_node,
+                                        "multiboot,ramdisk") == 0) ||
+             (fdt_node_check_compatible(fdt, module_node,
+                                        "multiboot,device-tree") == 0) )
+            /* The compatible is one of the strings above, check the module */
+            handle_dom0less_module_node(dir_handle, module_node, addr_cells,
+                                        size_cells);
+}
+
+/*
+ * This function checks for xen domain nodes under the /chosen node for 
possible
+ * domU guests to be loaded.
+ */
+static bool __init efi_arch_check_dom0less_boot(EFI_FILE_HANDLE dir_handle)
+{
+    int chosen;
+    int addr_len, size_len;
+    unsigned int i = 0;
+
+    /* Check for the chosen node in the current DTB */
+    chosen = setup_chosen_node(fdt, &addr_len, &size_len);
+    if ( chosen < 0 )
+        blexit(L"Unable to setup chosen node");
+
+    /* Check for nodes compatible with xen,domain under the chosen node */
+    for ( int node = fdt_first_subnode(fdt, chosen);
+          node > 0;
+          node = fdt_next_subnode(fdt, node) )
+    {
+        int addr_cells, size_cells, len;
+        const struct fdt_property *prop;
+
+        if ( fdt_node_check_compatible(fdt, node, "xen,domain") != 0 )
+            continue;
+
+        /* Get or set #address-cells and #size-cells */
+        prop = fdt_get_property(fdt, node, "#address-cells", &len);
+        if ( !prop )
+            blexit(L"#address-cells not found in domain node.");
+
+        addr_cells = fdt32_to_cpu(*((uint32_t *)prop->data));
+
+        prop = fdt_get_property(fdt, node, "#size-cells", &len);
+        if ( !prop )
+            blexit(L"#size-cells not found in domain node.");
+
+        size_cells = fdt32_to_cpu(*((uint32_t *)prop->data));
+
+        /* Found a node with compatible xen,domain; handle this node. */
+        handle_dom0less_domain_node(dir_handle, node, addr_cells, size_cells);
+    }
+
+    /* Free dom0less file names if any */
+    for ( ; i < dom0less_modules_idx; i++ )
+    {
+        /* Free dom0less binary names */
+        efi_bs->FreePool(dom0less_modules[i].name);
+    }
+
+    if ( dom0less_modules_idx > 0 )
+        return true;
+
+    return false;
 }
 
 static void __init efi_arch_cpu(void)
@@ -562,8 +806,19 @@ static void __init efi_arch_cpu(void)
 
 static void __init efi_arch_blexit(void)
 {
+    unsigned int i = 0;
+
     if ( dtbfile.need_to_free )
         efi_bs->FreePages(dtbfile.addr, PFN_UP(dtbfile.size));
+    /* Free dom0less files if any */
+    for ( ; i < dom0less_modules_idx; i++ )
+    {
+        /* Free dom0less binary names */
+        efi_bs->FreePool(dom0less_modules[i].name);
+        /* Free dom0less binaries */
+        efi_bs->FreePages(dom0less_modules[i].addr,
+                          PFN_UP(dom0less_modules[i].size));
+    }
     if ( memmap )
         efi_bs->FreePool(memmap);
 }
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 9b0cc29aae..950fdf16b7 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -678,6 +678,12 @@ static void __init efi_arch_handle_module(const struct 
file *file,
     efi_bs->FreePool(ptr);
 }
 
+static bool __init efi_arch_check_dom0less_boot(EFI_FILE_HANDLE dir_handle)
+{
+    /* x86 doesn't support dom0less */
+    return false;
+}
+
 static void __init efi_arch_cpu(void)
 {
     uint32_t eax = cpuid_eax(0x80000000);
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 758f9d74d2..7d8734199e 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -1127,15 +1127,16 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
     static EFI_GUID __initdata shim_lock_guid = SHIM_LOCK_PROTOCOL_GUID;
     EFI_LOADED_IMAGE *loaded_image;
     EFI_STATUS status;
-    unsigned int i, argc;
-    CHAR16 **argv, *file_name, *cfg_file_name = NULL, *options = NULL;
+    unsigned int i, argc = 0;
+    CHAR16 **argv, *file_name = NULL, *cfg_file_name = NULL, *options = NULL;
     UINTN gop_mode = ~0;
     EFI_SHIM_LOCK_PROTOCOL *shim_lock;
     EFI_GRAPHICS_OUTPUT_PROTOCOL *gop = NULL;
     union string section = { NULL }, name;
     bool base_video = false;
-    const char *option_str;
+    const char *option_str = NULL;
     bool use_cfg_file;
+    EFI_FILE_HANDLE dir_handle;
 
     __set_bit(EFI_BOOT, &efi_flags);
     __set_bit(EFI_LOADER, &efi_flags);
@@ -1216,9 +1217,11 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
 
     efi_arch_relocate_image(0);
 
+    /* Get the file system interface. */
+    dir_handle = get_parent_handle(loaded_image, &file_name);
+
     if ( use_cfg_file )
     {
-        EFI_FILE_HANDLE dir_handle;
         UINTN depth, cols, rows, size;
 
         size = cols = rows = depth = 0;
@@ -1229,9 +1232,6 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
 
         gop = efi_get_gop();
 
-        /* Get the file system interface. */
-        dir_handle = get_parent_handle(loaded_image, &file_name);
-
         /* Read and parse the config file. */
         if ( read_section(loaded_image, L"config", &cfg, NULL) )
             PrintStr(L"Using builtin config file\r\n");
@@ -1285,14 +1285,13 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
             efi_bs->FreePool(name.w);
         }
 
-        if ( !name.s )
-            blexit(L"No Dom0 kernel image specified.");
-
         efi_arch_cfg_file_early(loaded_image, dir_handle, section.s);
 
-        option_str = split_string(name.s);
+        if ( name.s )
+            option_str = split_string(name.s);
 
-        if ( !read_section(loaded_image, L"kernel", &kernel, option_str) )
+        if ( !read_section(loaded_image, L"kernel", &kernel, option_str) &&
+             name.s )
         {
             read_file(dir_handle, s2w(&name), &kernel, option_str);
             efi_bs->FreePool(name.w);
@@ -1361,12 +1360,21 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
         efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
         cfg.addr = 0;
 
-        dir_handle->Close(dir_handle);
-
         if ( gop && !base_video )
             gop_mode = efi_find_gop_mode(gop, cols, rows, depth);
     }
 
+    /*
+     * Check if a proper configuration is provided to start Xen:
+     *  - Dom0 specified (minimum required)
+     *  - Dom0 and DomU(s) specified
+     *  - DomU(s) specified
+     */
+    if ( !efi_arch_check_dom0less_boot(dir_handle) && !kernel.addr )
+        blexit(L"No Dom0 kernel image specified.");
+
+    dir_handle->Close(dir_handle);
+
     efi_arch_edd();
 
     /* XXX Collect EDID info. */
-- 
2.17.1




 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.