Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command line"

This reverts commit efc52d67e1.

Manually fixed conflicts in:
  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c

Note that besides re-exposing the kernel command line as a file in the
synthetic filesystem, we also revert back to AllocatePool instead of
AllocatePages.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3457
Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20210628105110.379951-4-dovmurik@linux.ibm.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c

@@ -33,6 +33,7 @@
 typedef enum {
   KernelBlobTypeKernel,
   KernelBlobTypeInitrd,
+  KernelBlobTypeCommandLine,
   KernelBlobTypeMax
 } KERNEL_BLOB_TYPE;
 
@@ -59,6 +60,11 @@ STATIC KERNEL_BLOB mKernelBlob[KernelBlobTypeMax] = {
     {
       { QemuFwCfgItemInitrdSize,      QemuFwCfgItemInitrdData,      },
     }
+  }, {
+    L"cmdline",
+    {
+      { QemuFwCfgItemCommandLineSize, QemuFwCfgItemCommandLineData, },
+    }
   }
 };
 
@@ -948,7 +954,7 @@ FetchBlob (
   //
   // Read blob.
   //
-  Blob->Data = AllocatePages (EFI_SIZE_TO_PAGES ((UINTN)Blob->Size));
+  Blob->Data = AllocatePool (Blob->Size);
   if (Blob->Data == NULL) {
     DEBUG ((DEBUG_ERROR, "%a: failed to allocate %Ld bytes for \"%s\"\n",
       __FUNCTION__, (INT64)Blob->Size, Blob->Name));
@@ -1083,8 +1089,7 @@ FreeBlobs:
   while (BlobType > 0) {
     CurrentBlob = &mKernelBlob[--BlobType];
     if (CurrentBlob->Data != NULL) {
-      FreePages (CurrentBlob->Data,
-        EFI_SIZE_TO_PAGES ((UINTN)CurrentBlob->Size));
+      FreePool (CurrentBlob->Data);
       CurrentBlob->Size = 0;
       CurrentBlob->Data = NULL;
     }