From 04c94fa6cb783ecbc8ce620222c91599b8d95777 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Date: Tue, 17 Nov 2015 10:14:57 -0500
Subject: [PATCH] EFI/early: Implement GetNextVariableName and /query and
 /noexitboot parameters

In the early EFI boot we will enumerate up to five EFI variables
to make sure it works.

The /query will just enumerate them and then quit. Helps in
troubleshooting and redirecting the output to a file (xen.efi /query > q).

The /noexitboot will inhibit Xen from calling ExitBootServices.
This allows on Lenovo ThinkPad x230, T420 to use GetNextVariableName
in 1-1 mapping mode.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 xen/common/efi/boot.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 89 insertions(+), 5 deletions(-)

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 53c7452..2e0d4c2 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -836,6 +836,75 @@ static void __init setup_efi_pci(void)
     efi_bs->FreePool(handles);
 }
 
+static int __init efi_getnextvariable(bool_t query_only)
+{
+    EFI_GUID guid;
+    UINTN i, size, idx;
+    CHAR16 *name;
+    EFI_STATUS status;
+
+
+    status = efi_bs->AllocatePool(EfiLoaderData, 1024, (void *)&name);
+    if ( EFI_ERROR(status) )
+        return status;
+
+    guid.Data1 = 0;
+    guid.Data2 = 0;
+    guid.Data3 = 0;
+    for ( i = 0; i < 8; i++ )
+        guid.Data4[i] = 0;
+
+    for ( i = 0 ; i < 1024 / sizeof (CHAR16); i++ )
+        name[i] = 0;
+
+    PrintStr(L"GetNextVariableName: ");
+    PrintStr(name);
+    PrintStr(newline);
+    idx = 0;
+    do {
+        size = 1024;
+        efi_rs->GetNextVariableName(&size, name, &guid);
+        if ( EFI_ERROR(status) )
+        {
+            if ( query_only )
+            {
+                efi_bs->FreePool(name);
+                PrintErrMesg(L"Failed to GetNextVariableName", status);
+            }
+            else
+            {
+                PrintStr(L"Warning: GetNextVariableName: ");
+                DisplayUint(status, 0);
+                PrintStr(newline);
+            }
+        }
+        else
+        {
+            DisplayUint(guid.Data1, 4);
+            DisplayUint(guid.Data2, 2);
+            DisplayUint(guid.Data3, 2);
+            for ( i = 0; i < 8; i++ )
+                DisplayUint(guid.Data4[i], 1);
+
+            PrintStr(L":");
+            PrintStr(name);
+            PrintStr(L" ");
+            DisplayUint(status, 0);
+            PrintStr(newline);
+        }
+    } while ( !EFI_ERROR(status) && idx++ < 5 );
+
+    efi_bs->FreePool(name);
+
+    if ( query_only )
+        return -EINVAL;
+
+    if ( EFI_ERROR(EFI_NOT_FOUND) )
+        return 0;
+
+    return status;
+}
+
 static void __init efi_variables(void)
 {
     EFI_STATUS status;
@@ -875,7 +944,7 @@ static void __init efi_set_gop_mode(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop, UINTN gop
         efi_arch_video_init(gop, info_size, mode_info);
 }
 
-static void __init efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
+static void __init efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable, bool_t exitbootservices)
 {
     EFI_STATUS status;
     UINTN info_size = 0, map_key;
@@ -903,9 +972,13 @@ static void __init efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *Syste
 
         efi_arch_pre_exit_boot();
 
-        status = SystemTable->BootServices->ExitBootServices(ImageHandle,
-                                                             map_key);
-        efi_bs = NULL;
+        status = 0;
+        if ( exitbootservices )
+        {
+            status = SystemTable->BootServices->ExitBootServices(ImageHandle,
+                                                                 map_key);
+            efi_bs = NULL;
+        }
         if ( status != EFI_INVALID_PARAMETER || retry )
             break;
     }
@@ -951,8 +1024,10 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     EFI_GRAPHICS_OUTPUT_PROTOCOL *gop = NULL;
     union string section = { NULL }, name;
     bool_t base_video = 0;
+    bool_t query_only = 0;
     char *option_str;
     bool_t use_cfg_file;
+    bool_t exit_boot_services = 1;
 
     efi_init(ImageHandle, SystemTable);
 
@@ -990,6 +1065,10 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
                     base_video = 1;
                 else if ( wstrcmp(ptr + 1, L"mapbs") == 0 )
                     map_bs = 1;
+                else if ( wstrcmp(ptr + 1, L"query") == 0 )
+                    query_only = 1;
+                else if ( wstrcmp(ptr + 1, L"noexitboot") == 0 )
+                    exit_boot_services = 0;
                 else if ( wstrncmp(ptr + 1, L"cfg=", 4) == 0 )
                     cfg_file_name = ptr + 5;
                 else if ( i + 1 < argc && wstrcmp(ptr + 1, L"cfg") == 0 )
@@ -1000,6 +1079,8 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
                     PrintStr(L"Xen EFI Loader options:\r\n");
                     PrintStr(L"-basevideo   retain current video mode\r\n");
                     PrintStr(L"-mapbs       map EfiBootServices{Code,Data}\r\n");
+                    PrintStr(L"-noexitboot  do not call ExitBootServices\r\n");
+                    PrintStr(L"-query       call GetNextVariableName for up to five times\r\n");
                     PrintStr(L"-cfg=<file>  specify configuration file\r\n");
                     PrintStr(L"-help, -?    display this help\r\n");
                     blexit(NULL);
@@ -1160,12 +1241,15 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     /* Get snapshot of variable store parameters. */
     efi_variables();
 
+    if ( efi_getnextvariable(query_only) )
+       blexit(L"Could not get next variable");
+
     efi_arch_memory_setup();
 
     if ( gop )
         efi_set_gop_mode(gop, gop_mode);
 
-    efi_exit_boot(ImageHandle, SystemTable);
+    efi_exit_boot(ImageHandle, SystemTable, exit_boot_services);
 
     efi_arch_post_exit_boot();
     for( ; ; ); /* not reached */
-- 
2.1.0