Cornelia Huck noticed that a modular virtio without kvm guest support
leads to a build error in the s390 virtio transport:
CONFIG_VIRTIO=m leads to
ERROR: "vmem_add_mapping" [drivers/s390/kvm/kvm_virtio.ko] undefined!
ERROR: "max_pfn" [drivers/s390/kvm/kvm_virtio.ko] undefined!
ERROR: "vmem_remove_mapping" [drivers/s390/kvm/kvm_virtio.ko] undefined!
The virtio transport only works with kvm guest support and only as a
builtin. Lets change the build process of drivers/s390/kvm/kvm_virtio.c
to depend on kvm guest support, which is also a bool.
CONFIG_S390_GUEST already selects CONFIG_VIRTIO, that should prevent
CONFIG_S390_GUEST=y CONFIG_VIRTIO=n situations.
CC: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.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: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
