This patch implements config_changed for the s390 virtio transport.

We use the least significant bit of the interrupt parameter field
to decide, if this interrupt should call the virtio virtqueue callback
or the config_changed callback.

This method is compatible with old host and guest code. Old 64 bit guests
will not check the bit and trigger a harmless additional vring_interrupt
call. Old host code will never set this bit, this is also safe.

This patch also takes care of a potential future 31 bit virtio transport
for s390. On 31 bit _LC_PFAULT_INTPARM and __LC_EXT_PARAMS are identical.
We exploit the alignment of the token and fold the change bit into the
lsb of the token itself.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This allows each virtio user to hand in the alignment appropriate to
their virtio_ring structures.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This doesn't really matter, since s390 pagesize is 4k anyway.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The current virtio model on s390 has the descriptor page above the main
memory. The guest virtio detection will oops if the mem= parameter is
used to reduce/change the memory size.
We have to use real_memory_size instead of max_pfn to detect the virtio
descriptor pages.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

No need to define a static device for the kvm_s390 root device,
just use s390_root_dev_register().

This is needed for the bus_id rework
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix these two false positive warnings:

WARNING: vmlinux.o(.text+0x2e1cc4): Section mismatch in reference from the function s390_virtio_console_init() to the function .init.text:early_put_chars()
The function s390_virtio_console_init() references
the function __init early_put_chars().
This is often because s390_virtio_console_init lacks a __init
annotation or the annotation of early_put_chars is wrong.

WARNING: vmlinux.o(.text+0x2e1cd0): Section mismatch in reference from the function s390_virtio_console_init() to the function .init.text:virtio_cons_early_init()
The function s390_virtio_console_init() references
the function __init virtio_cons_early_init().
This is often because s390_virtio_console_init lacks a __init
annotation or the annotation of virtio_cons_early_init is wrong.

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

To prepare for virtio_ring transport feature bits, hook in a call in
all the users to manipulate them.  This currently just clears all the
bits, since it doesn't understand any features.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Rather than explicitly handing the features to the lower-level, we just
hand the virtio_device and have it set the features.  This make it clear
that it has the chance to manipulate the features of the device at this
point (and that all feature negotiation is already done).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch enables virtio_console as the default console on kvm for
s390. We currently use the same notify hack as lguest for early
console output. I will try to address this for lguest and s390 later.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Anthony Liguori points out that three different transports use the virtio code,
but each one keeps its own counter to set the virtio_device's index field.  In
theory (though not in current practice) this means that names could be
duplicated, and that risk grows as more transports are created.

So we move the selection of the unique virtio_device.index into the common code
in virtio.c, which has the side-benefit of removing duplicate code.

The only complexity is that lguest and S/390 use the index to uniquely identify
the device in case of catastrophic failure before register_virtio_device() is
called: now we use the offset within the descriptor page as a unique identifier
for the printks.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chris Lalancette <clalance@redhat.com>
Cc: Anthony Liguori <anthony@codemonkey.ws>

Fix kvm compile error:

Commit c45a6816
(virtio: explicit advertisement of driver features)
and commit e976a2b9
(s390: KVM guest: virtio device support, and kvm hypercalls)
don't like each other:

  CC      drivers/s390/kvm/kvm_virtio.o
drivers/s390/kvm/kvm_virtio.c:224: error: unknown field 'feature' specified in initializer
drivers/s390/kvm/kvm_virtio.c:224: warning: initialization from incompatible pointer type
make[3]: *** [drivers/s390/kvm/kvm_virtio.o] Error 1

Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Convert s390 to SPARSEMEM and SPARSEMEM_VMEMMAP. We do a select
of SPARSEMEM_VMEMMAP since it is configurable. This is because
SPARSEMEM without SPARSEMEM_VMEMMAP gives us a hell of broken
include dependencies that I don't want to fix.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This patch implements kvm guest kernel support for paravirtualized devices
and contains two parts:
o a basic virtio stub using virtio_ring and external interrupts and hypercalls
o full hypercall implementation in kvm_para.h

Currently we dont have PCI on s390. Making virtio_pci usable for s390 seems
more complicated that providing an own stub. This virtio stub is similar to
the lguest one, the memory for the descriptors and the device detection is made
via additional mapped memory on top of the guest storage. We use an external
interrupt with extint code 0x2603 for host->guest notification.

The hypercall definition uses the diag instruction for issuing a hypercall. The
parameters are written in R2-R7, the hypercall number is written in R1. This is
similar to the system call ABI (svc) which can use R1 for the number and R2-R6
for the parameters.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>