original_kernel/arch/ia64/kvm/Kconfig

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#
# KVM configuration
#
source "virt/kvm/Kconfig"
menuconfig VIRTUALIZATION
bool "Virtualization"
depends on HAVE_KVM || IA64
default y
---help---
Say Y here to get to see options for using your Linux host to run other
operating systems inside virtual machines (guests).
This option alone does not add any kernel code.
If you say N, all options in this submenu will be skipped and disabled.
if VIRTUALIZATION
config KVM
tristate "Kernel-based Virtual Machine (KVM) support"
depends on BROKEN
depends on HAVE_KVM && MODULES
depends on BROKEN
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
select KVM_APIC_ARCHITECTURE
select KVM_MMIO
---help---
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
processor equipped with virtualization extensions. You will also
need to select one or more of the processor modules below.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
To compile this as a module, choose M here: the module
will be called kvm.
If unsure, say N.
config KVM_INTEL
tristate "KVM for Intel Itanium 2 processors support"
depends on KVM && m
---help---
Provides support for KVM on Itanium 2 processors equipped with the VT
extensions.
config KVM_DEVICE_ASSIGNMENT
bool "KVM legacy PCI device assignment support"
depends on KVM && PCI && IOMMU_API
default y
---help---
Provide support for legacy PCI device assignment through KVM. The
kernel now also supports a full featured userspace device driver
framework through VFIO, which supersedes much of this support.
If unsure, say Y.
vhost_net: a kernel-level virtio server What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration, bug work-arounds in userspace) - write logging is supported (good for migration) - support memory table and not just an offset (needed for kvm) common virtio related code has been put in a separate file vhost.c and can be made into a separate module if/when more backends appear. I used Rusty's lguest.c as the source for developing this part : this supplied me with witty comments I wouldn't be able to write myself. What it is not: vhost net is not a bus, and not a generic new system call. No assumptions are made on how guest performs hypercalls. Userspace hypervisors are supported as well as kvm. How it works: Basically, we connect virtio frontend (configured by userspace) to a backend. The backend could be a network device, or a tap device. Backend is also configured by userspace, including vlan/mac etc. Status: This works for me, and I haven't see any crashes. Compared to userspace, people reported improved latency (as I save up to 4 system calls per packet), as well as better bandwidth and CPU utilization. Features that I plan to look at in the future: - mergeable buffers - zero copy - scalability tuning: figure out the best threading model to use Note on RCU usage (this is also documented in vhost.h, near private_pointer which is the value protected by this variant of RCU): what is happening is that the rcu_dereference() is being used in a workqueue item. The role of rcu_read_lock() is taken on by the start of execution of the workqueue item, of rcu_read_unlock() by the end of execution of the workqueue item, and of synchronize_rcu() by flush_workqueue()/flush_work(). In the future we might need to apply some gcc attribute or sparse annotation to the function passed to INIT_WORK(). Paul's ack below is for this RCU usage. (Includes fixes by Alan Cox <alan@linux.intel.com>, David L Stevens <dlstevens@us.ibm.com>, Chris Wright <chrisw@redhat.com>) Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-14 14:17:27 +08:00
source drivers/vhost/Kconfig
endif # VIRTUALIZATION