path: root/Documentation/virtual/kvm/api.txt
diff options
Diffstat (limited to 'Documentation/virtual/kvm/api.txt')
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 59a38264a0ed..6386f8c0482e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1169,6 +1169,14 @@ following flags are specified:
/* Depends on KVM_CAP_IOMMU */
+/* The following two depend on KVM_CAP_PCI_2_3 */
+#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
+#define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)
+If KVM_DEV_ASSIGN_PCI_2_3 is set, the kernel will manage legacy INTx interrupts
+via the PCI-2.3-compliant device-level mask, thus enable IRQ sharing with other
+assigned devices or host devices. KVM_DEV_ASSIGN_MASK_INTX specifies the
+guest's view on the INTx mask, see KVM_ASSIGN_SET_INTX_MASK for details.
The KVM_DEV_ASSIGN_ENABLE_IOMMU flag is a mandatory option to ensure
isolation of the device. Usages not specifying this flag are deprecated.
@@ -1441,6 +1449,39 @@ The "num_dirty" field is a performance hint for KVM to determine whether it
should skip processing the bitmap and just invalidate everything. It must
be set to the number of set bits in the bitmap.
+Capability: KVM_CAP_PCI_2_3
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_assigned_pci_dev (in)
+Returns: 0 on success, -1 on error
+Allows userspace to mask PCI INTx interrupts from the assigned device. The
+kernel will not deliver INTx interrupts to the guest between setting and
+clearing of KVM_ASSIGN_SET_INTX_MASK via this interface. This enables use of
+and emulation of PCI 2.3 INTx disable command register behavior.
+This may be used for both PCI 2.3 devices supporting INTx disable natively and
+older devices lacking this support. Userspace is responsible for emulating the
+read value of the INTx disable bit in the guest visible PCI command register.
+When modifying the INTx disable state, userspace should precede updating the
+physical device command register by calling this ioctl to inform the kernel of
+the new intended INTx mask state.
+Note that the kernel uses the device INTx disable bit to internally manage the
+device interrupt state for PCI 2.3 devices. Reads of this register may
+therefore not match the expected value. Writes should always use the guest
+intended INTx disable value rather than attempting to read-copy-update the
+current physical device state. Races between user and kernel updates to the
+INTx disable bit are handled lazily in the kernel. It's possible the device
+may generate unintended interrupts, but they will not be injected into the
+See KVM_ASSIGN_DEV_IRQ for the data structure. The target device is specified
+by assigned_dev_id. In the flags field, only KVM_DEV_ASSIGN_MASK_INTX is