[PATCH 15/15] x86/PVH: simplify writing of Dom0's RSDP

[Jan Beulich <jbeulich@xxxxxxxx>]

Now that we establish where the RSDP is to live before actually loading
the kernel (and writing start-info there) we can simply hand the pointer
there, eliminating the need for the (fragile) separate write to the field
out of pvh_setup_acpi().

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Alternatively we could move start_info to the top-level function, have
pvh_load_kernel() and pvh_setup_acpi() fill what need filling, and do
the write from the top-level function. Yet it looks to me as if this was
more churn for little extra gain.

--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -976,7 +976,8 @@ static int __init pvh_load_kernel(
     const struct boot_domain *bd,
     struct elf_binary *elf,
     struct hvm_modlist_entry *mod,
-    paddr_t *start_info_addr)
+    paddr_t *start_info_addr,
+    paddr_t rsdp)
 {
     struct domain *d = bd->d;
     struct boot_module *initrd = bd->initrd;
@@ -1110,6 +1111,7 @@ static int __init pvh_load_kernel(
 
     start_info.magic = XEN_HVM_START_MAGIC_VALUE;
     start_info.flags = SIF_PRIVILEGED | SIF_INITDOMAIN;
+    start_info.rsdp_paddr = rsdp;
     rc = hvm_copy_to_guest_phys(last_addr, &start_info, sizeof(start_info), v);
     if ( rc )
     {
@@ -1587,10 +1589,7 @@ static int __init pvh_place_acpi(
     return 0;
 }
 
-static int __init pvh_setup_acpi(
-    struct domain *d,
-    struct acpi_info *info,
-    paddr_t start_info)
+static int __init pvh_setup_acpi(struct domain *d, struct acpi_info *info)
 {
     int rc;
     struct acpi_table_rsdp *native_rsdp, rsdp = {
@@ -1642,20 +1641,6 @@ static int __init pvh_setup_acpi(
         return rc;
     }
 
-    /* Copy RSDP address to start_info. */
-    BUILD_BUG_ON(sizeof(info->rsdp) !=
-                 sizeof_field(struct hvm_start_info, rsdp_paddr));
-    rc = hvm_copy_to_guest_phys(start_info +
-                                offsetof(struct hvm_start_info, rsdp_paddr),
-                                &info->rsdp,
-                                sizeof_field(struct hvm_start_info, 
rsdp_paddr),
-                                d->vcpu[0]);
-    if ( rc )
-    {
-        printk("Unable to copy RSDP address to start info\n");
-        return rc;
-    }
-
     return 0;
 }
 
@@ -1783,7 +1768,7 @@ int __init dom0_construct_pvh(const stru
 
     xvfree(orig_e820);
 
-    rc = pvh_load_kernel(bd, &elf, &initrd, &start_info);
+    rc = pvh_load_kernel(bd, &elf, &initrd, &start_info, acpi.rsdp);
     if ( rc )
     {
         printk("Failed to load Dom0 kernel\n");
@@ -1797,7 +1782,7 @@ int __init dom0_construct_pvh(const stru
         return rc;
     }
 
-    rc = pvh_setup_acpi(d, &acpi, start_info);
+    rc = pvh_setup_acpi(d, &acpi);
     if ( rc )
     {
         printk("Failed to setup Dom0 ACPI tables: %d\n", rc);