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KVM: s390: Add support for channel I/O instructions.

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Add a new capability, KVM_CAP_S390_CSS_SUPPORT, which will pass
intercepts for channel I/O instructions to userspace. Only I/O
instructions interacting with I/O interrupts need to be handled
in-kernel:

- TEST PENDING INTERRUPTION (tpi) dequeues and stores pending
  interrupts entirely in-kernel.
- TEST SUBCHANNEL (tsch) dequeues pending interrupts in-kernel
  and exits via KVM_EXIT_S390_TSCH to userspace for subchannel-
  related processing.

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Cornelia Huck
2012-12-20 15:32:12 +01:00
committed by Marcelo Tosatti
parent d6712df95b
commit fa6b7fe992
10 changed files with 202 additions and 5 deletions
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30
Documentation/virtual/kvm/api.txt
View File

@@ -2350,6 +2350,22 @@ The possible hypercalls are defined in the Power Architecture Platform
Requirements (PAPR) document available from www.power.org (free
developer registration required to access it).
/* KVM_EXIT_S390_TSCH */
struct {
__u16 subchannel_id;
__u16 subchannel_nr;
__u32 io_int_parm;
__u32 io_int_word;
__u32 ipb;
__u8 dequeued;
} s390_tsch;
s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled
and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O
interrupt for the target subchannel has been dequeued and subchannel_id,
subchannel_nr, io_int_parm and io_int_word contain the parameters for that
interrupt. ipb is needed for instruction parameter decoding.
/* Fix the size of the union. */
char padding[256];
};
@@ -2471,3 +2487,17 @@ For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV:
where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value.
- The tsize field of mas1 shall be set to 4K on TLB0, even though the
hardware ignores this value for TLB0.
6.4 KVM_CAP_S390_CSS_SUPPORT
Architectures: s390
Parameters: none
Returns: 0 on success; -1 on error
This capability enables support for handling of channel I/O instructions.
TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are
handled in-kernel, while the other I/O instructions are passed to userspace.
When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST
SUBCHANNEL intercepts.