From f19c6e5fe79c8bbd3c9ea25cd0380681bd99ce13 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Thu, 22 May 2014 22:32:53 +0200
Subject: [PATCH] vm: Use a para-virtualized disk when creating an image.

* guix/build/vm.scm (load-in-linux-vm): When MAKE-DISK-IMAGE?, use
  '-drive ...,if=virtio' for better performance.
* gnu/system/vm.scm (qemu-image): Use /dev/vda instead of /dev/sda.
---
 gnu/system/vm.scm | 2 +-
 guix/build/vm.scm | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm
index 39ce5bb6ef..7d0ffd971e 100644
--- a/gnu/system/vm.scm
+++ b/gnu/system/vm.scm
@@ -236,7 +236,7 @@ the image."
           (let ((graphs '#$(match inputs
                              (((names . _) ...)
                               names))))
-            (initialize-hard-disk "/dev/sda"
+            (initialize-hard-disk "/dev/vda"
                                   #:grub.cfg #$grub-configuration
                                   #:closures graphs
                                   #:copy-closures? #$copy-inputs?
diff --git a/guix/build/vm.scm b/guix/build/vm.scm
index 4de536abb4..e559542f0a 100644
--- a/guix/build/vm.scm
+++ b/guix/build/vm.scm
@@ -96,7 +96,8 @@ the #:references-graphs parameter of 'derivation'."
                   "-append" (string-append "console=ttyS0 --load="
                                            builder)
                   (if make-disk-image?
-                      `("-hda" ,image-file)
+                      `("-drive" ,(string-append "file=" image-file
+                                                 ",if=virtio"))
                       '())))
     (error "qemu failed" qemu))