[PATCH 1/2] xen/x86/pvh: use preset XSDT header for XSDT generation

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

From: Stefano Stabellini <stefano.stabellini@xxxxxxx>

Xen always generates a XSDT table even if the firmware provided a RSDT
table. Instead of copying the XSDT header from the firmware table (that
might be missing), generate the XSDT header from a preset.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
---
 xen/arch/x86/hvm/dom0_build.c | 32 +++++++++-----------------------
 1 file changed, 9 insertions(+), 23 deletions(-)

diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index 307edc6a8c..5fde769863 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -963,13 +963,18 @@ static int __init pvh_setup_acpi_xsdt(struct domain *d, 
paddr_t madt_addr,
                                       paddr_t *addr)
 {
     struct acpi_table_xsdt *xsdt;
-    struct acpi_table_header *table;
-    struct acpi_table_rsdp *rsdp;
     const struct acpi_table_desc *tables = acpi_gbl_root_table_list.tables;
     unsigned long size = sizeof(*xsdt);
     unsigned int i, j, num_tables = 0;
-    paddr_t xsdt_paddr;
     int rc;
+    struct acpi_table_header header = {
+        .signature    = "XSDT",
+        .length       = sizeof(struct acpi_table_header),
+        .revision     = 0x1,
+        .oem_id       = "Xen",
+        .oem_table_id = "HVM",
+        .oem_revision = 0,
+    };
 
     /*
      * Restore original DMAR table signature, we are going to filter it from
@@ -1001,26 +1006,7 @@ static int __init pvh_setup_acpi_xsdt(struct domain *d, 
paddr_t madt_addr,
         goto out;
     }
 
-    /* Copy the native XSDT table header. */
-    rsdp = acpi_os_map_memory(acpi_os_get_root_pointer(), sizeof(*rsdp));
-    if ( !rsdp )
-    {
-        printk("Unable to map RSDP\n");
-        rc = -EINVAL;
-        goto out;
-    }
-    xsdt_paddr = rsdp->xsdt_physical_address;
-    acpi_os_unmap_memory(rsdp, sizeof(*rsdp));
-    table = acpi_os_map_memory(xsdt_paddr, sizeof(*table));
-    if ( !table )
-    {
-        printk("Unable to map XSDT\n");
-        rc = -EINVAL;
-        goto out;
-    }
-    xsdt->header = *table;
-    acpi_os_unmap_memory(table, sizeof(*table));
-
+    xsdt->header = header;
     /* Add the custom MADT. */
     xsdt->table_offset_entry[0] = madt_addr;
 
-- 
2.25.1