KVM: PPC: Remove 440 support

The 440 target hasn't been properly functioning for a few releases and
before I was the only one who fixes a very serious bug that indicates to
me that nobody used it before either.

Furthermore KVM on 440 is slow to the extent of unusable.

We don't have to carry along completely unused code. Remove 440 and give
us one less thing to worry about.

Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 0 insertions, 43 deletions

diff --git a/Documentation/powerpc/00-INDEX b/Documentation/powerpc/00-INDEX
index 6db73df0427..a68784d0a1e 100644
--- a/Documentation/powerpc/00-INDEX
+++ b/Documentation/powerpc/00-INDEX
@@ -17,8 +17,6 @@ firmware-assisted-dump.txt
 	- Documentation on the firmware assisted dump mechanism "fadump".
 hvcs.txt
 	- IBM "Hypervisor Virtual Console Server" Installation Guide
-kvm_440.txt
-	- Various notes on the implementation of KVM for PowerPC 440.
 mpc52xx.txt
 	- Linux 2.6.x on MPC52xx family
 pmu-ebb.txt
diff --git a/Documentation/powerpc/kvm_440.txt b/Documentation/powerpc/kvm_440.txt
deleted file mode 100644
index c02a003fa03..00000000000
--- a/Documentation/powerpc/kvm_440.txt
+++ /dev/null
@@ -1,41 +0,0 @@
-Hollis Blanchard <hollisb@us.ibm.com>
-15 Apr 2008
-
-Various notes on the implementation of KVM for PowerPC 440:
-
-To enforce isolation, host userspace, guest kernel, and guest userspace all
-run at user privilege level. Only the host kernel runs in supervisor mode.
-Executing privileged instructions in the guest traps into KVM (in the host
-kernel), where we decode and emulate them. Through this technique, unmodified
-440 Linux kernels can be run (slowly) as guests. Future performance work will
-focus on reducing the overhead and frequency of these traps.
-
-The usual code flow is started from userspace invoking an "run" ioctl, which
-causes KVM to switch into guest context. We use IVPR to hijack the host
-interrupt vectors while running the guest, which allows us to direct all
-interrupts to kvmppc_handle_interrupt(). At this point, we could either
-- handle the interrupt completely (e.g. emulate "mtspr SPRG0"), or
-- let the host interrupt handler run (e.g. when the decrementer fires), or
-- return to host userspace (e.g. when the guest performs device MMIO)
-
-Address spaces: We take advantage of the fact that Linux doesn't use the AS=1
-address space (in host or guest), which gives us virtual address space to use
-for guest mappings. While the guest is running, the host kernel remains mapped
-in AS=0, but the guest can only use AS=1 mappings.
-
-TLB entries: The TLB entries covering the host linear mapping remain
-present while running the guest. This reduces the overhead of lightweight
-exits, which are handled by KVM running in the host kernel. We keep three
-copies of the TLB:
- - guest TLB: contents of the TLB as the guest sees it
- - shadow TLB: the TLB that is actually in hardware while guest is running
- - host TLB: to restore TLB state when context switching guest -> host
-When a TLB miss occurs because a mapping was not present in the shadow TLB,
-but was present in the guest TLB, KVM handles the fault without invoking the
-guest. Large guest pages are backed by multiple 4KB shadow pages through this
-mechanism.
-
-IO: MMIO and DCR accesses are emulated by userspace. We use virtio for network
-and block IO, so those drivers must be enabled in the guest. It's possible
-that some qemu device emulation (e.g. e1000 or rtl8139) may also work with
-little effort.