[v2 1/1] doc: Show how to boot result of 'vm-image'.

[Leo Famulari <leo@famulari.name>]

* doc/guix.texi (Running GuixSD in a VM): New node.
(Invoking guix system): Add reference to 'Running GuixSD in a VM'.
---
 doc/guix.texi | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 55 insertions(+), 3 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 4ce6ef5..cd5ced4 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -15,8 +15,8 @@ Copyright @copyright{} 2013, 2014 Andreas Enge@*
 Copyright @copyright{} 2013 Nikita Karetnikov@*
 Copyright @copyright{} 2015 Mathieu Lirzin@*
 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
-Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer
-Copyright @copyright{} 2015 Leo Famulari
+Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
+Copyright @copyright{} 2015, 2016 Leo Famulari
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -174,6 +174,7 @@ System Configuration
 * Initial RAM Disk::            Linux-Libre bootstrapping.
 * GRUB Configuration::          Configuring the boot loader.
 * Invoking guix system::        Instantiating a system configuration.
+* Running GuixSD in a VM::      How to run GuixSD in a virtual machine.
 * Defining Services::           Adding new service definitions.
 
 Services
@@ -5693,6 +5694,7 @@ instance to support new system services.
 * Initial RAM Disk::            Linux-Libre bootstrapping.
 * GRUB Configuration::          Configuring the boot loader.
 * Invoking guix system::        Instantiating a system configuration.
+* Running GuixSD in a VM::      How to run GuixSD in a virtual machine.
 * Defining Services::           Adding new service definitions.
 @end menu
 
@@ -9193,7 +9195,8 @@ in @var{file} that stands alone.  Use the @option{--image-size} option
 to specify the size of the image.
 
 When using @code{vm-image}, the returned image is in qcow2 format, which
-the QEMU emulator can efficiently use.
+the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
+for more information on how to run the image in a virtual machine.
 
 When using @code{disk-image}, a raw disk image is produced; it can be
 copied as is to a USB stick, for instance.  Assuming @code{/dev/sdc} is
@@ -9332,6 +9335,55 @@ graph} of dmd services of the operating system defined in @var{file}.
 
 @end table
 
+@node Running GuixSD in a VM
+@subsection Running GuixSD in a VM
+
+One way to run GuixSD in a virtual machine is to build a GuixSD virtual
+machine image using @command{guix system vm-image} (@pxref{Invoking guix
+system}). The returned image is in qcow2 format, which the
+@uref{http://qemu.org/, QEMU emulator} can efficiently use.
+
+To run the image in QEMU, copy it out of the store (@pxref{The Store})
+and give yourself permission to write to the copy. When invoking QEMU,
+you must choose a system emulator that is suitable for your hardware
+platform. Here is a minimal QEMU invocation that will boot the result of
+@command{guix system vm-image} on x86_64 hardware:
+
+@example
+$ qemu-system-x86_64 \
+-net user -net nic,model=virtio \
+-enable-kvm -m 256 /tmp/qemu-image
+@end example
+
+And the annotated version:
+
+@table @code
+@item qemu-system-x86_64
+This specifies the hardware platform to emulate. This should match the
+host.
+
+@item -net user
+Enable the unprivileged user-mode network stack. The guest OS can access
+the host but not vice versa. This is the simplest way to get the guest
+OS online. If you don't choose a network stack, the boot will fail.
+
+@item -net nic,model=virtio
+You must create a network interface of a given model. If you don't
+create a NIC, the boot will fail. Assuming your hardware platform is
+x86_64, you can get a list of available NIC models by running
+`qemu-system-x86_64 -net nic,model=help`.
+
+@item -enable-kvm
+If your system has hardware virtualization extensions, enabling the
+kernel virtual machine will make things run faster.
+
+@item -m 256
+RAM available to the guest OS, in megabytes. Defaults to 128 megabytes,
+which is not enough for the Guix daemon.
+
+@item /tmp/qemu-image
+The filesystem path of the qcow2 image.
+@end table
 
 @node Defining Services
 @subsection Defining Services
-- 
2.7.0.rc3