On 16.05.20 00:19, Collin Walling wrote: > DIAGNOSE 0x318 (diag 318) sets information regarding the environment > the VM is running in (Linux, z/VM, etc) and is observed via > firmware/service events. > > This is a privileged s390x instruction that must be intercepted by > SIE. Userspace handling is required, so let's introduce some functions > to communicate between userspace and KVM via ioctls. These will be used > to get/set the diag 318 related information. > > The Control Program Name Code (CPNC) is stored in the SIE block. The > CPNC along with the Control Program Version Code (CPVC) are stored in > the kvm_arch struct. > > Signed-off-by: Collin Walling <walling@xxxxxxxxxxxxx> > --- > Documentation/virt/kvm/devices/vm.rst | 21 +++++++ > arch/s390/include/asm/kvm_host.h | 5 +- > arch/s390/include/uapi/asm/kvm.h | 4 ++ > arch/s390/kvm/kvm-s390.c | 82 +++++++++++++++++++++++++++ > arch/s390/kvm/vsie.c | 2 + > 5 files changed, 113 insertions(+), 1 deletion(-) > > diff --git a/Documentation/virt/kvm/devices/vm.rst b/Documentation/virt/kvm/devices/vm.rst > index 0aa5b1cfd700..52cc906dd7bd 100644 > --- a/Documentation/virt/kvm/devices/vm.rst > +++ b/Documentation/virt/kvm/devices/vm.rst > @@ -314,3 +314,24 @@ Allows userspace to query the status of migration mode. > if it is enabled > :Returns: -EFAULT if the given address is not accessible from kernel space; > 0 in case of success. > + > +6. GROUP: KVM_S390_VM_MISC > +========================== > + > +:Architectures: s390 > + > +6.1. KVM_S390_VM_MISC_DIAG_318 (r/w) > +----------------------------------- > + > +Allows userspace to retrieve and set the DIAGNOSE 0x318 information, > +which consists of a 1-byte "Control Program Name Code" and a 7-byte > +"Control Program Version Code" (a 64 bit value all in all). This > +information is set by the guest (usually during IPL). This interface is > +intended to allow retrieving and setting it during migration; while no > +real harm is done if the information is changed outside of migration, > +it is strongly discouraged. > + > +:Parameters: address of a buffer in user space (u64), where the > + information is read from or stored into > +:Returns: -EFAULT if the given address is not accessible from kernel space; > + 0 in case of success An alternative would be a new sync_reg value + KVM capability.
