path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-02 14:50:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-02 14:50:10 -0700
commit7cbb39d4d4d530dff12f2ff06ed6c85c504ba91a (patch)
tree82f721591d739eca99817def86ca5b6ebd682fe6 /Documentation
parent64056a94256e7a476de67fbe581dfe5515c56288 (diff)
parent7227fc0666606b0df2c0d2966a7f4859b01bdf74 (diff)
Merge tag 'kvm-3.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini: "PPC and ARM do not have much going on this time. Most of the cool stuff, instead, is in s390 and (after a few releases) x86. ARM has some caching fixes and PPC has transactional memory support in guests. MIPS has some fixes, with more probably coming in 3.16 as QEMU will soon get support for MIPS KVM. For x86 there are optimizations for debug registers, which trigger on some Windows games, and other important fixes for Windows guests. We now expose to the guest Broadwell instruction set extensions and also Intel MPX. There's also a fix/workaround for OS X guests, nested virtualization features (preemption timer), and a couple kvmclock refinements. For s390, the main news is asynchronous page faults, together with improvements to IRQs (floating irqs and adapter irqs) that speed up virtio devices" * tag 'kvm-3.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (96 commits) KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8 KVM: PPC: Book3S HV: Fix decrementer timeouts with non-zero TB offset KVM: PPC: Book3S HV: Don't use kvm_memslots() in real mode KVM: PPC: Book3S HV: Return ENODEV error rather than EIO KVM: PPC: Book3S: Trim top 4 bits of physical address in RTAS code KVM: PPC: Book3S HV: Add get/set_one_reg for new TM state KVM: PPC: Book3S HV: Add transactional memory support KVM: Specify byte order for KVM_EXIT_MMIO KVM: vmx: fix MPX detection KVM: PPC: Book3S HV: Fix KVM hang with CONFIG_KVM_XICS=n KVM: PPC: Book3S: Introduce hypervisor call H_GET_TCE KVM: PPC: Book3S HV: Fix incorrect userspace exit on ioeventfd write KVM: s390: clear local interrupts at cpu initial reset KVM: s390: Fix possible memory leak in SIGP functions KVM: s390: fix calculation of idle_mask array size KVM: s390: randomize sca address KVM: ioapic: reinject pending interrupts on KVM_SET_IRQCHIP KVM: Bump KVM_MAX_IRQ_ROUTES for s390 KVM: s390: irq routing for adapter interrupts. KVM: s390: adapter interrupt sources ...
Diffstat (limited to 'Documentation')
2 files changed, 131 insertions, 7 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 6cd63a9010f..c24211da412 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -586,8 +586,8 @@ struct kvm_fpu {
-Capability: KVM_CAP_IRQCHIP
-Architectures: x86, ia64, ARM, arm64
+Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390)
+Architectures: x86, ia64, ARM, arm64, s390
Type: vm ioctl
Parameters: none
Returns: 0 on success, -1 on error
@@ -596,7 +596,10 @@ Creates an interrupt controller model in the kernel. On x86, creates a virtual
ioapic, a virtual PIC (two PICs, nested), and sets up future vcpus to have a
local APIC. IRQ routing for GSIs 0-15 is set to both PIC and IOAPIC; GSI 16-23
only go to the IOAPIC. On ia64, a IOSAPIC is created. On ARM/arm64, a GIC is
+created. On s390, a dummy irq routing table is created.
+Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled
+before KVM_CREATE_IRQCHIP can be used.
@@ -612,6 +615,20 @@ On some architectures it is required that an interrupt controller model has
been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered
interrupts require the level to be set to 1 and then back to 0.
+On real hardware, interrupt pins can be active-low or active-high. This
+does not matter for the level field of struct kvm_irq_level: 1 always
+means active (asserted), 0 means inactive (deasserted).
+x86 allows the operating system to program the interrupt polarity
+(active-low/active-high) for level-triggered interrupts, and KVM used
+to consider the polarity. However, due to bitrot in the handling of
+active-low interrupts, the above convention is now valid on x86 too.
+This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace
+should not present interrupts to the guest as active-low unless this
+capability is present (or unless it is not using the in-kernel irqchip,
+of course).
ARM/arm64 can signal an interrupt either at the CPU level, or at the
in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to
use PPIs designated for specific cpus. The irq field is interpreted
@@ -628,7 +645,7 @@ The irq_type field has the following values:
(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs)
-In both cases, level is used to raise/lower the line.
+In both cases, level is used to assert/deassert the line.
struct kvm_irq_level {
union {
@@ -918,9 +935,9 @@ documentation when it pops into existence).
Architectures: ppc, s390
-Type: vcpu ioctl
+Type: vcpu ioctl, vm ioctl (with KVM_CAP_ENABLE_CAP_VM)
Parameters: struct kvm_enable_cap (in)
Returns: 0 on success; -1 on error
@@ -951,6 +968,8 @@ function properly, this is the place to put them.
__u8 pad[64];
+The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl
+for vm-wide capabilities.
@@ -1320,7 +1339,7 @@ KVM_ASSIGN_DEV_IRQ. Partial deassignment of host or guest IRQ is allowed.
-Architectures: x86 ia64
+Architectures: x86 ia64 s390
Type: vm ioctl
Parameters: struct kvm_irq_routing (in)
Returns: 0 on success, -1 on error
@@ -1343,6 +1362,7 @@ struct kvm_irq_routing_entry {
union {
struct kvm_irq_routing_irqchip irqchip;
struct kvm_irq_routing_msi msi;
+ struct kvm_irq_routing_s390_adapter adapter;
__u32 pad[8];
} u;
@@ -1350,6 +1370,7 @@ struct kvm_irq_routing_entry {
/* gsi routing entry types */
No flags are specified so far, the corresponding field must be set to zero.
@@ -1365,6 +1386,14 @@ struct kvm_irq_routing_msi {
__u32 pad;
+struct kvm_irq_routing_s390_adapter {
+ __u64 ind_addr;
+ __u64 summary_addr;
+ __u64 ind_offset;
+ __u32 summary_offset;
+ __u32 adapter_id;
@@ -2566,6 +2595,10 @@ executed a memory-mapped I/O instruction which could not be satisfied
by kvm. The 'data' member contains the written data if 'is_write' is
true, and should be filled by application code otherwise.
+The 'data' member contains, in its first 'len' bytes, the value as it would
+appear if the VCPU performed a load or store of the appropriate width directly
+to the byte array.
KVM_EXIT_PAPR and KVM_EXIT_EPR the corresponding
operations are complete (and guest state is consistent) only after userspace
diff --git a/Documentation/virtual/kvm/devices/s390_flic.txt b/Documentation/virtual/kvm/devices/s390_flic.txt
new file mode 100644
index 00000000000..4ceef53164b
--- /dev/null
+++ b/Documentation/virtual/kvm/devices/s390_flic.txt
@@ -0,0 +1,91 @@
+FLIC (floating interrupt controller)
+FLIC handles floating (non per-cpu) interrupts, i.e. I/O, service and some
+machine check interruptions. All interrupts are stored in a per-vm list of
+pending interrupts. FLIC performs operations on this list.
+Only one FLIC instance may be instantiated.
+FLIC provides support to
+- add interrupts (KVM_DEV_FLIC_ENQUEUE)
+- inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS)
+- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS)
+- enable/disable for the guest transparent async page faults
+- register and modify adapter interrupt sources (KVM_DEV_FLIC_ADAPTER_*)
+ Passes a buffer and length into the kernel which are then injected into
+ the list of pending interrupts.
+ attr->addr contains the pointer to the buffer and attr->attr contains
+ the length of the buffer.
+ The format of the data structure kvm_s390_irq as it is copied from userspace
+ is defined in usr/include/linux/kvm.h.
+ Copies all floating interrupts into a buffer provided by userspace.
+ When the buffer is too small it returns -ENOMEM, which is the indication
+ for userspace to try again with a bigger buffer.
+ All interrupts remain pending, i.e. are not deleted from the list of
+ currently pending interrupts.
+ attr->addr contains the userspace address of the buffer into which all
+ interrupt data will be copied.
+ attr->attr contains the size of the buffer in bytes.
+ Simply deletes all elements from the list of currently pending floating
+ interrupts. No interrupts are injected into the guest.
+ Enables async page faults for the guest. So in case of a major page fault
+ the host is allowed to handle this async and continues the guest.
+ Disables async page faults for the guest and waits until already pending
+ async page faults are done. This is necessary to trigger a completion interrupt
+ for every init interrupt before migrating the interrupt list.
+ Register an I/O adapter interrupt source. Takes a kvm_s390_io_adapter
+ describing the adapter to register:
+struct kvm_s390_io_adapter {
+ __u32 id;
+ __u8 isc;
+ __u8 maskable;
+ __u8 swap;
+ __u8 pad;
+ id contains the unique id for the adapter, isc the I/O interruption subclass
+ to use, maskable whether this adapter may be masked (interrupts turned off)
+ and swap whether the indicators need to be byte swapped.
+ Modifies attributes of an existing I/O adapter interrupt source. Takes
+ a kvm_s390_io_adapter_req specifiying the adapter and the operation:
+struct kvm_s390_io_adapter_req {
+ __u32 id;
+ __u8 type;
+ __u8 mask;
+ __u16 pad0;
+ __u64 addr;
+ id specifies the adapter and type the operation. The supported operations
+ are:
+ mask or unmask the adapter, as specified in mask
+ perform a gmap translation for the guest address provided in addr,
+ pin a userspace page for the translated address and add it to the
+ list of mappings
+ release a userspace page for the translated address specified in addr
+ from the list of mappings