linux.git/Documentation/virtual/kvm/devices, branch v4.9

KVM: arm64: Require in-kernel irqchip for PMU support

2016-09-27T16:57:07+00:00

If userspace creates a PMU for the VCPU, but doesn't create an in-kernel
irqchip, then we end up in a nasty path where we try to take an
uninitialized spinlock, which can lead to all sorts of breakages.

Luckily, QEMU always creates the VGIC before the PMU, so we can
establish this as ABI and check for the VGIC in the PMU init stage.
This can be relaxed at a later time if we want to support PMU with a
userspace irqchip.

Cc: stable@vger.kernel.org
Cc: Shannon Zhao 
Acked-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm/arm64: Add VGICv3 save/restore API documentation

2016-09-08T10:53:00+00:00

Factor out the GICv3 and ITS-specific documentation into a separate
documentation file.  Add description for how to access distributor,
redistributor, and CPU interface registers for GICv3 in this new file,
and add a group for accessing level triggered IRQ information for GICv3
as well.

Reviewed-by: Marc Zyngier 
Reviewed-by: Peter Maydell 
Signed-off-by: Christoffer Dall

KVM: arm64: vgic-its: Introduce new KVM ITS device

2016-07-18T17:14:35+00:00

Introduce a new KVM device that represents an ARM Interrupt Translation
Service (ITS) controller. Since there can be multiple of this per guest,
we can't piggy back on the existing GICv3 distributor device, but create
a new type of KVM device.
On the KVM_CREATE_DEVICE ioctl we allocate and initialize the ITS data
structure and store the pointer in the kvm_device data.
Upon an explicit init ioctl from userland (after having setup the MMIO
address) we register the handlers with the kvm_io_bus framework.
Any reference to an ITS thus has to go via this interface.

Signed-off-by: Andre Przywara 
Reviewed-by: Marc Zyngier 
Tested-by: Eric Auger 
Signed-off-by: Marc Zyngier

KVM: s390: provide CMMA attributes only if available

2016-06-10T10:07:20+00:00

Let's not provide the device attribute for cmma enabling and clearing
if the hardware doesn't support it.

This also helps getting rid of the undocumented return value "-EINVAL"
in case CMMA is not available when trying to enable it.

Also properly document the meaning of -EINVAL for CMMA clearing.

Reviewed-by: Christian Borntraeger 
Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger

KVM: s390: interface to query and configure cpu subfunctions

2016-06-10T10:07:17+00:00

We have certain instructions that indicate available subfunctions via
a query subfunction (crypto functions and ptff), or via a test bit
function (plo).

By exposing these "subfunction blocks" to user space, we allow user space
to
1) query available subfunctions and make sure subfunctions won't get lost
   during migration - e.g. properly indicate them via a CPU model
2) change the subfunctions to be reported to the guest (even adding
   unavailable ones)

This mechanism works just like the way we indicate the stfl(e) list to
user space.

This way, user space could even emulate some subfunctions in QEMU in the
future. If this is ever applicable, we have to make sure later on, that
unsupported subfunctions result in an intercept to QEMU.

Please note that support to indicate them to the guest is still missing
and requires hardware support. Usually, the IBC takes already care of these
subfunctions for migration safety. QEMU should make sure to always set
these bits properly according to the machine generation to be emulated.

Available subfunctions are only valid in combination with STFLE bits
retrieved via KVM_S390_VM_CPU_MACHINE and enabled via
KVM_S390_VM_CPU_PROCESSOR. If the applicable bits are available, the
indicated subfunctions are guaranteed to be correct.

Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger

KVM: s390: interface to query and configure cpu features

2016-06-10T10:07:13+00:00

For now, we only have an interface to query and configure facilities
indicated via STFL(E). However, we also have features indicated via
SCLP, that have to be indicated to the guest by user space and usually
require KVM support.

This patch allows user space to query and configure available cpu features
for the guest.

Please note that disabling a feature doesn't necessarily mean that it is
completely disabled (e.g. ESOP is mostly handled by the SIE). We will try
our best to disable it.

Most features (e.g. SCLP) can't directly be forwarded, as most of them need
in addition to hardware support, support in KVM. As we later on want to
turn these features in KVM explicitly on/off (to simulate different
behavior), we have to filter all features provided by the hardware and
make them configurable.

Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger

Documentation: virtual: fix spelling mistake

2016-04-25T14:59:49+00:00

Signed-off-by: Eric Engestrom 
Acked-by: Cornelia Huck 
Signed-off-by: Radim Krčmář

KVM: s390: add clear I/O irq operation for FLIC

2016-04-20T12:27:32+00:00

Introduce a FLIC operation for clearing I/O interrupts for a subchannel.

Rationale: According to the platform specification, pending I/O
interruption requests have to be revoked in certain situations. For
instance, according to the Principles of Operation (page 17-27), a
subchannel put into the installed parameters initialized state is in the
same state as after an I/O system reset (just parameters possibly changed).
This implies that any I/O interrupts for that subchannel are no longer
pending (as I/O system resets clear I/O interrupts). Therefore, we need an
interface to clear pending I/O interrupts.

Signed-off-by: Halil Pasic 
Reviewed-by: Cornelia Huck 
Reviewed-by: Christian Borntraeger 
Signed-off-by: Christian Borntraeger 
Signed-off-by: Cornelia Huck

KVM: s390: document FLIC behavior on unsupported

2016-04-20T12:27:32+00:00

FLIC behavior deviates from the API documentation in reporting EINVAL
instead of ENXIO for KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR when the group
or attribute is unknown/unsupported. Unfortunately this can not be fixed
for historical reasons. Let us at least have it documented.

Signed-off-by: Halil Pasic 
Reviewed-by: Cornelia Huck 
Reviewed-by: Christian Borntraeger 
Signed-off-by: Christian Borntraeger 
Signed-off-by: Cornelia Huck

Merge tag 'kvm-arm-for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2016-03-09T10:50:42+00:00

KVM/ARM updates for 4.6

- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- Various optimizations to the vgic save/restore code

Conflicts:
	include/uapi/linux/kvm.h