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[Xen-devel] [PATCH v6 14/22] arm/acpi: Create min DT stub for Dom0



From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>

Create a DT for Dom0 for ACPI-case only. DT contains minimal required
informations such as Dom0 bootargs, initrd, efi description table and
address of uefi memory table.

Also port the document of this device tree bindings from Linux.

Signed-off-by: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 docs/misc/arm/device-tree/uefi.txt |  58 +++++++++++++++
 xen/arch/arm/domain_build.c        | 143 +++++++++++++++++++++++++++++++++++++
 xen/arch/arm/efi/efi-dom0.c        |  48 +++++++++++++
 xen/include/asm-arm/setup.h        |   2 +
 4 files changed, 251 insertions(+)
 create mode 100644 docs/misc/arm/device-tree/uefi.txt

diff --git a/docs/misc/arm/device-tree/uefi.txt 
b/docs/misc/arm/device-tree/uefi.txt
new file mode 100644
index 0000000..41a8be0
--- /dev/null
+++ b/docs/misc/arm/device-tree/uefi.txt
@@ -0,0 +1,58 @@
+* Xen hypervisor device tree bindings
+
+Xen ARM virtual platforms shall have a top-level "hypervisor" node with
+the following properties:
+
+- compatible:
+       compatible = "xen,xen-<version>", "xen,xen";
+  where <version> is the version of the Xen ABI of the platform.
+
+- reg: specifies the base physical address and size of a region in
+  memory where the grant table should be mapped to, using an
+  HYPERVISOR_memory_op hypercall. The memory region is large enough to map
+  the whole grant table (it is larger or equal to gnttab_max_grant_frames()).
+
+- interrupts: the interrupt used by Xen to inject event notifications.
+  A GIC node is also required.
+
+To support UEFI on Xen ARM virtual platforms, Xen populates the FDT "uefi" node
+under /hypervisor with following parameters:
+
+________________________________________________________________________________
+Name                      | Size   | Description
+================================================================================
+xen,uefi-system-table     | 64-bit | Guest physical address of the UEFI System
+                          |        | Table.
+--------------------------------------------------------------------------------
+xen,uefi-mmap-start       | 64-bit | Guest physical address of the UEFI memory
+                          |        | map.
+--------------------------------------------------------------------------------
+xen,uefi-mmap-size        | 32-bit | Size in bytes of the UEFI memory map
+                          |        | pointed to in previous entry.
+--------------------------------------------------------------------------------
+xen,uefi-mmap-desc-size   | 32-bit | Size in bytes of each entry in the UEFI
+                          |        | memory map.
+--------------------------------------------------------------------------------
+xen,uefi-mmap-desc-ver    | 32-bit | Version of the mmap descriptor format.
+--------------------------------------------------------------------------------
+
+Example (assuming #address-cells = <2> and #size-cells = <2>):
+
+hypervisor {
+       compatible = "xen,xen-4.3", "xen,xen";
+       reg = <0 0xb0000000 0 0x20000>;
+       interrupts = <1 15 0xf08>;
+       uefi {
+               xen,uefi-system-table = <0xXXXXXXXX>;
+               xen,uefi-mmap-start = <0xXXXXXXXX>;
+               xen,uefi-mmap-size = <0xXXXXXXXX>;
+               xen,uefi-mmap-desc-size = <0xXXXXXXXX>;
+               xen,uefi-mmap-desc-ver = <0xXXXXXXXX>;
+        };
+};
+
+The format and meaning of the "xen,uefi-*" parameters are similar to those in
+Documentation/arm/uefi.txt in Linux, which are provided by the regular Linux
+UEFI stub. However they differ because they are provided by the Xen hypervisor,
+together with a set of UEFI runtime services implemented via hypercalls, see
+xen/include/public/platform.h.
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index e036887..6726e45 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1357,6 +1357,145 @@ static int prepare_dtb(struct domain *d, struct 
kernel_info *kinfo)
 }
 
 #ifdef CONFIG_ACPI
+#define ACPI_DOM0_FDT_MIN_SIZE 4096
+
+static int make_chosen_node(const struct kernel_info *kinfo,
+                            struct membank tbl_add[])
+{
+    int res;
+    const char *bootargs = NULL;
+    const struct bootmodule *mod = kinfo->kernel_bootmodule;
+    void *fdt = kinfo->fdt;
+
+    DPRINT("Create chosen node\n");
+    res = fdt_begin_node(fdt, "chosen");
+    if ( res )
+        return res;
+
+    if ( mod && mod->cmdline[0] )
+    {
+        bootargs = &mod->cmdline[0];
+        res = fdt_property(fdt, "bootargs", bootargs, strlen(bootargs) + 1);
+        if ( res )
+           return res;
+    }
+
+    /*
+     * If the bootloader provides an initrd, we must create a placeholder
+     * for the initrd properties. The values will be replaced later.
+     */
+    if ( mod && mod->size )
+    {
+        u64 a = 0;
+        res = fdt_property(kinfo->fdt, "linux,initrd-start", &a, sizeof(a));
+        if ( res )
+            return res;
+
+        res = fdt_property(kinfo->fdt, "linux,initrd-end", &a, sizeof(a));
+        if ( res )
+            return res;
+    }
+
+    res = fdt_end_node(fdt);
+
+    return res;
+}
+
+static int acpi_make_hypervisor_node(const struct kernel_info *kinfo,
+                                     struct membank tbl_add[])
+{
+    const char compat[] =
+        "xen,xen-"__stringify(XEN_VERSION)"."__stringify(XEN_SUBVERSION)"\0"
+        "xen,xen";
+    int res;
+    /* Convenience alias */
+    void *fdt = kinfo->fdt;
+
+    DPRINT("Create hypervisor node\n");
+
+    /* See linux Documentation/devicetree/bindings/arm/xen.txt */
+    res = fdt_begin_node(fdt, "hypervisor");
+    if ( res )
+        return res;
+
+    /* Cannot use fdt_property_string due to embedded nulls */
+    res = fdt_property(fdt, "compatible", compat, sizeof(compat));
+    if ( res )
+        return res;
+
+    res = arm_acpi_make_efi_nodes(fdt, tbl_add);
+    if ( res )
+        return res;
+
+    res = fdt_end_node(fdt);
+
+    return res;
+}
+
+/*
+ * Prepare a minimal DTB for Dom0 which contains bootargs, initrd, memory
+ * information, EFI table.
+ */
+static int create_acpi_dtb(struct kernel_info *kinfo, struct membank tbl_add[])
+{
+    int new_size;
+    int ret;
+
+    DPRINT("Prepare a min DTB for DOM0\n");
+
+    /* Allocate min size for DT */
+    new_size = ACPI_DOM0_FDT_MIN_SIZE;
+    kinfo->fdt = xmalloc_bytes(new_size);
+
+    if ( kinfo->fdt == NULL )
+        return -ENOMEM;
+
+    /* Create a new empty DT for DOM0 */
+    ret = fdt_create(kinfo->fdt, new_size);
+    if ( ret < 0 )
+        goto err;
+
+    ret = fdt_finish_reservemap(kinfo->fdt);
+    if ( ret < 0 )
+        goto err;
+
+    ret = fdt_begin_node(kinfo->fdt, "/");
+    if ( ret < 0 )
+        goto err;
+
+    ret = fdt_property_cell(kinfo->fdt, "#address-cells", 2);
+    if ( ret )
+        return ret;
+
+    ret = fdt_property_cell(kinfo->fdt, "#size-cells", 1);
+    if ( ret )
+        return ret;
+
+    /* Create a chosen node for DOM0 */
+    ret = make_chosen_node(kinfo, tbl_add);
+    if ( ret )
+        goto err;
+
+    ret = acpi_make_hypervisor_node(kinfo, tbl_add);
+    if ( ret )
+        goto err;
+
+    ret = fdt_end_node(kinfo->fdt);
+    if ( ret < 0 )
+        goto err;
+
+    ret = fdt_finish(kinfo->fdt);
+    if ( ret < 0 )
+        goto err;
+
+    return 0;
+
+  err:
+    printk("Device tree generation failed (%d).\n", ret);
+    xfree(kinfo->fdt);
+    return -EINVAL;
+}
+
 static void acpi_map_other_tables(struct domain *d)
 {
     int i;
@@ -1706,6 +1845,10 @@ static int prepare_acpi(struct domain *d, struct 
kernel_info *kinfo)
         return rc;
     }
 
+    rc = create_acpi_dtb(kinfo, tbl_add);
+    if ( rc != 0 )
+        return rc;
+
     return 0;
 }
 #else
diff --git a/xen/arch/arm/efi/efi-dom0.c b/xen/arch/arm/efi/efi-dom0.c
index 3ffde94..688fa8b 100644
--- a/xen/arch/arm/efi/efi-dom0.c
+++ b/xen/arch/arm/efi/efi-dom0.c
@@ -24,6 +24,7 @@
 #include "efi.h"
 #include "efi-dom0.h"
 #include <xen/pfn.h>
+#include <xen/libfdt/libfdt.h>
 #include <asm/setup.h>
 #include <asm/acpi.h>
 
@@ -132,3 +133,50 @@ void __init acpi_create_efi_mmap_table(paddr_t paddr, 
paddr_t size,
     tbl_add[TBL_MMAP].size = sizeof(EFI_MEMORY_DESCRIPTOR)
                              * (mem->nr_banks + acpi_mem.nr_banks + 1);
 }
+
+/* Create place holder for efi values. */
+int __init arm_acpi_make_efi_nodes(void *fdt, struct membank tbl_add[])
+{
+    u64 fdt_val64;
+    u32 fdt_val32;
+    int desc_ver = 1;
+    int res;
+
+    res = fdt_begin_node(fdt, "uefi");
+    if ( res )
+        return res;
+
+    fdt_val64 = cpu_to_fdt64(tbl_add[TBL_EFIT].start);
+    res = fdt_property(fdt, "xen,uefi-system-table",
+                       &fdt_val64, sizeof(fdt_val64));
+    if ( res )
+        return res;
+
+    fdt_val64 = cpu_to_fdt64(tbl_add[TBL_MMAP].start);
+    res = fdt_property(fdt, "xen,uefi-mmap-start",
+                       &fdt_val64,  sizeof(fdt_val64));
+    if ( res )
+        return res;
+
+    fdt_val32 = cpu_to_fdt32(tbl_add[TBL_MMAP].size);
+    res = fdt_property(fdt, "xen,uefi-mmap-size",
+                       &fdt_val32,  sizeof(fdt_val32));
+    if ( res )
+        return res;
+
+    fdt_val32 = cpu_to_fdt32(sizeof(EFI_MEMORY_DESCRIPTOR));
+    res = fdt_property(fdt, "xen,uefi-mmap-desc-size",
+                         &fdt_val32, sizeof(fdt_val32));
+    if ( res )
+        return res;
+
+    fdt_val32 = cpu_to_fdt32(desc_ver);
+    res = fdt_property(fdt, "xen,uefi-mmap-desc-ver",
+                         &fdt_val32, sizeof(fdt_val32));
+    if ( res )
+        return res;
+
+    res = fdt_end_node(fdt);
+
+    return res;
+}
diff --git a/xen/include/asm-arm/setup.h b/xen/include/asm-arm/setup.h
index b2899f2..05f0210 100644
--- a/xen/include/asm-arm/setup.h
+++ b/xen/include/asm-arm/setup.h
@@ -61,6 +61,8 @@ void acpi_create_efi_mmap_table(paddr_t paddr, paddr_t size,
                                 const struct meminfo *mem,
                                 struct membank tbl_add[]);
 
+int arm_acpi_make_efi_nodes(void *fdt, struct membank tbl_add[]);
+
 int construct_dom0(struct domain *d);
 
 void discard_initial_modules(void);
-- 
2.0.4



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