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authorSteve Rutherford <srutherford@google.com>2015-07-29 23:21:41 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2015-10-01 15:06:27 +0200
commit7543a635aa09eb138b2cbf60ac3ff19503ae6954 (patch)
tree94d181962c2a3f64019f182900ed216a2f0c3e73 /Documentation
parent49df6397edfc5a8ba8ca813b51fb9729d8e94b40 (diff)
KVM: x86: Add KVM exit for IOAPIC EOIs
Adds KVM_EXIT_IOAPIC_EOI which allows the kernel to EOI level-triggered IOAPIC interrupts. Uses a per VCPU exit bitmap to decide whether or not the IOAPIC needs to be informed (which is identical to the EOI_EXIT_BITMAP field used by modern x86 processors, but can also be used to elide kvm IOAPIC EOI exits on older processors). [Note: A prototype using ResampleFDs found that decoupling the EOI from the VCPU's thread made it possible for the VCPU to not see a recent EOI after reentering the guest. This does not match real hardware.] Compile tested for Intel x86. Signed-off-by: Steve Rutherford <srutherford@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/virtual/kvm/api.txt12
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 43e0816d0de1..0d14bf5db534 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3309,6 +3309,18 @@ Valid values for 'type' are:
to ignore the request, or to gather VM memory core dump and/or
reset/shutdown of the VM.
+ /* KVM_EXIT_IOAPIC_EOI */
+ struct {
+ __u8 vector;
+ } eoi;
+
+Indicates that the VCPU's in-kernel local APIC received an EOI for a
+level-triggered IOAPIC interrupt. This exit only triggers when the
+IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled);
+the userspace IOAPIC should process the EOI and retrigger the interrupt if
+it is still asserted. Vector is the LAPIC interrupt vector for which the
+EOI was received.
+
/* Fix the size of the union. */
char padding[256];
};