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| author | David Hildenbrand <david@redhat.com> | 2024-10-25 16:14:46 +0200 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2024-11-07 10:26:24 +0100 |
| commit | b7cfc045488e89157a0908783171abf8e6808084 (patch) | |
| tree | c52d32c26a744d67cb3dd452ea859e7a76620fac /Documentation/virt | |
| parent | s390/kvm: Mask extra bits from program interrupt code (diff) | |
| download | linux-b7cfc045488e89157a0908783171abf8e6808084.tar.xz linux-b7cfc045488e89157a0908783171abf8e6808084.zip | |
Documentation: s390-diag.rst: Make diag500 a generic KVM hypercall
Let's make it a generic KVM hypercall, allowing other subfunctions to
be more independent of virtio.
While at it, document that unsupported/unimplemented subfunctions result
in a SPECIFICATION exception.
This is a preparation for documenting a new subfunction.
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241025141453.1210600-2-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/s390/s390-diag.rst | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/Documentation/virt/kvm/s390/s390-diag.rst b/Documentation/virt/kvm/s390/s390-diag.rst index ca85f030eb0b..48a326d41cc0 100644 --- a/Documentation/virt/kvm/s390/s390-diag.rst +++ b/Documentation/virt/kvm/s390/s390-diag.rst @@ -35,20 +35,24 @@ DIAGNOSE function codes not specific to KVM, please refer to the documentation for the s390 hypervisors defining them. -DIAGNOSE function code 'X'500' - KVM virtio functions ------------------------------------------------------ +DIAGNOSE function code 'X'500' - KVM functions +---------------------------------------------- -If the function code specifies 0x500, various virtio-related functions -are performed. +If the function code specifies 0x500, various KVM-specific functions +are performed, including virtio functions. -General register 1 contains the virtio subfunction code. Supported -virtio subfunctions depend on KVM's userspace. Generally, userspace -provides either s390-virtio (subcodes 0-2) or virtio-ccw (subcode 3). +General register 1 contains the subfunction code. Supported subfunctions +depend on KVM's userspace. Regarding virtio subfunctions, generally +userspace provides either s390-virtio (subcodes 0-2) or virtio-ccw +(subcode 3). Upon completion of the DIAGNOSE instruction, general register 2 contains the function's return code, which is either a return code or a subcode specific value. +If the specified subfunction is not supported, a SPECIFICATION exception +will be triggered. + Subcode 0 - s390-virtio notification and early console printk Handled by userspace. |