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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-16 13:01:42 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-16 13:01:42 -0800 |
commit | 44024adb4aabefd275c6f9c00cac323473447dd5 (patch) | |
tree | 386e7975f0702729eaf0cd596c9b385825d7d257 /Documentation/virt/kvm/devices/xics.rst | |
parent | b982df72ef8404de99597f1d956b6137533b429a (diff) | |
parent | 120881b9e888689cbdb90a1dd1689684d8bc95f3 (diff) |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"Bugfixes and improvements to selftests.
On top of this, Mauro converted the KVM documentation to rst format,
which was very welcome"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits)
docs: virt: guest-halt-polling.txt convert to ReST
docs: kvm: review-checklist.txt: rename to ReST
docs: kvm: Convert timekeeping.txt to ReST format
docs: kvm: Convert s390-diag.txt to ReST format
docs: kvm: Convert ppc-pv.txt to ReST format
docs: kvm: Convert nested-vmx.txt to ReST format
docs: kvm: Convert mmu.txt to ReST format
docs: kvm: Convert locking.txt to ReST format
docs: kvm: Convert hypercalls.txt to ReST format
docs: kvm: arm/psci.txt: convert to ReST
docs: kvm: convert arm/hyp-abi.txt to ReST
docs: kvm: Convert api.txt to ReST format
docs: kvm: convert devices/xive.txt to ReST
docs: kvm: convert devices/xics.txt to ReST
docs: kvm: convert devices/vm.txt to ReST
docs: kvm: convert devices/vfio.txt to ReST
docs: kvm: convert devices/vcpu.txt to ReST
docs: kvm: convert devices/s390_flic.txt to ReST
docs: kvm: convert devices/mpic.txt to ReST
docs: kvm: convert devices/arm-vgit.txt to ReST
...
Diffstat (limited to 'Documentation/virt/kvm/devices/xics.rst')
-rw-r--r-- | Documentation/virt/kvm/devices/xics.rst | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/devices/xics.rst b/Documentation/virt/kvm/devices/xics.rst new file mode 100644 index 000000000000..2d6927e0b776 --- /dev/null +++ b/Documentation/virt/kvm/devices/xics.rst @@ -0,0 +1,92 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +XICS interrupt controller +========================= + +Device type supported: KVM_DEV_TYPE_XICS + +Groups: + 1. KVM_DEV_XICS_GRP_SOURCES + Attributes: + + One per interrupt source, indexed by the source number. + 2. KVM_DEV_XICS_GRP_CTRL + Attributes: + + 2.1 KVM_DEV_XICS_NR_SERVERS (write only) + + The kvm_device_attr.addr points to a __u32 value which is the number of + interrupt server numbers (ie, highest possible vcpu id plus one). + + Errors: + + ======= ========================================== + -EINVAL Value greater than KVM_MAX_VCPU_ID. + -EFAULT Invalid user pointer for attr->addr. + -EBUSY A vcpu is already connected to the device. + ======= ========================================== + +This device emulates the XICS (eXternal Interrupt Controller +Specification) defined in PAPR. The XICS has a set of interrupt +sources, each identified by a 20-bit source number, and a set of +Interrupt Control Presentation (ICP) entities, also called "servers", +each associated with a virtual CPU. + +The ICP entities are created by enabling the KVM_CAP_IRQ_ARCH +capability for each vcpu, specifying KVM_CAP_IRQ_XICS in args[0] and +the interrupt server number (i.e. the vcpu number from the XICS's +point of view) in args[1] of the kvm_enable_cap struct. Each ICP has +64 bits of state which can be read and written using the +KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctls on the vcpu. The 64 bit +state word has the following bitfields, starting at the +least-significant end of the word: + +* Unused, 16 bits + +* Pending interrupt priority, 8 bits + Zero is the highest priority, 255 means no interrupt is pending. + +* Pending IPI (inter-processor interrupt) priority, 8 bits + Zero is the highest priority, 255 means no IPI is pending. + +* Pending interrupt source number, 24 bits + Zero means no interrupt pending, 2 means an IPI is pending + +* Current processor priority, 8 bits + Zero is the highest priority, meaning no interrupts can be + delivered, and 255 is the lowest priority. + +Each source has 64 bits of state that can be read and written using +the KVM_GET_DEVICE_ATTR and KVM_SET_DEVICE_ATTR ioctls, specifying the +KVM_DEV_XICS_GRP_SOURCES attribute group, with the attribute number being +the interrupt source number. The 64 bit state word has the following +bitfields, starting from the least-significant end of the word: + +* Destination (server number), 32 bits + + This specifies where the interrupt should be sent, and is the + interrupt server number specified for the destination vcpu. + +* Priority, 8 bits + + This is the priority specified for this interrupt source, where 0 is + the highest priority and 255 is the lowest. An interrupt with a + priority of 255 will never be delivered. + +* Level sensitive flag, 1 bit + + This bit is 1 for a level-sensitive interrupt source, or 0 for + edge-sensitive (or MSI). + +* Masked flag, 1 bit + + This bit is set to 1 if the interrupt is masked (cannot be delivered + regardless of its priority), for example by the ibm,int-off RTAS + call, or 0 if it is not masked. + +* Pending flag, 1 bit + + This bit is 1 if the source has a pending interrupt, otherwise 0. + +Only one XICS instance may be created per VM. |