qemu linux2.img -hdb nbd:unix:/tmp/my_socket
@end example
+If the nbd-server uses named exports (since NBD 2.9.18), you must use the
+"exportname" option:
+@example
+qemu -cdrom nbd:localhost:exportname=debian-500-ppc-netinst
+qemu -cdrom nbd:localhost:exportname=openSUSE-11.1-ppc-netinst
+@end example
+
@node pcsys_network
@section Network emulation
that span several QEMU instances. See @ref{sec_invocation} to have a
basic example.
+@section Other Devices
+
+@subsection Inter-VM Shared Memory device
+
+With KVM enabled on a Linux host, a shared memory device is available. Guests
+map a POSIX shared memory region into the guest as a PCI device that enables
+zero-copy communication to the application level of the guests. The basic
+syntax is:
+
+@example
+qemu -device ivshmem,size=<size in format accepted by -m>[,shm=<shm name>]
+@end example
+
+If desired, interrupts can be sent between guest VMs accessing the same shared
+memory region. Interrupt support requires using a shared memory server and
+using a chardev socket to connect to it. The code for the shared memory server
+is qemu.git/contrib/ivshmem-server. An example syntax when using the shared
+memory server is:
+
+@example
+qemu -device ivshmem,size=<size in format accepted by -m>[,chardev=<id>]
+ [,msi=on][,ioeventfd=on][,vectors=n][,role=peer|master]
+qemu -chardev socket,path=<path>,id=<id>
+@end example
+
+When using the server, the guest will be assigned a VM ID (>=0) that allows guests
+using the same server to communicate via interrupts. Guests can read their
+VM ID from a device register (see example code). Since receiving the shared
+memory region from the server is asynchronous, there is a (small) chance the
+guest may boot before the shared memory is attached. To allow an application
+to ensure shared memory is attached, the VM ID register will return -1 (an
+invalid VM ID) until the memory is attached. Once the shared memory is
+attached, the VM ID will return the guest's valid VM ID. With these semantics,
+the guest application can check to ensure the shared memory is attached to the
+guest before proceeding.
+
+The @option{role} argument can be set to either master or peer and will affect
+how the shared memory is migrated. With @option{role=master}, the guest will
+copy the shared memory on migration to the destination host. With
+@option{role=peer}, the guest will not be able to migrate with the device attached.
+With the @option{peer} case, the device should be detached and then reattached
+after migration using the PCI hotplug support.
+
@node direct_linux_boot
@section Direct Linux Boot
-prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single'
@end example
-@item -M [SS-4|SS-5|SS-10|SS-20|SS-600MP|LX|Voyager|SPARCClassic|SPARCbook|SS-2|SS-1000|SS-2000]
+@item -M [SS-4|SS-5|SS-10|SS-20|SS-600MP|LX|Voyager|SPARCClassic] [|SPARCbook|SS-2|SS-1000|SS-2000]
Set the emulated machine type. Default is SS-5.
@subsection Command line options
@example
-usage: qemu-i386 [-h] [-d] [-L path] [-s size] [-cpu model] [-g port] [-B offset] program [arguments...]
+usage: qemu-i386 [-h] [-d] [-L path] [-s size] [-cpu model] [-g port] [-B offset] [-R size] program [arguments...]
@end example
@table @option
Select CPU model (-cpu ? for list and additional feature selection)
@item -B offset
Offset guest address by the specified number of bytes. This is useful when
-the address region rewuired by guest applications is reserved on the host.
-Ths option is currently only supported on some hosts.
+the address region required by guest applications is reserved on the host.
+This option is currently only supported on some hosts.
+@item -R size
+Pre-allocate a guest virtual address space of the given size (in bytes).
+"G", "M", and "k" suffixes may be used when specifying the size.
@end table
Debug options:
projects / qemu.git / blobdiff