We want to prevent from losing interrupts while they are masked. The
way they can be lost is due to the internals of how they are connected
through KVM. An eventfd is registered to a specific GSI, and then a
route is associated with this same GSI.
The current code adds/removes a route whenever a mask/unmask action
happens. Problem with this approach, KVM will consume the eventfd but
it won't be able to find an associated route and eventually it won't
be able to deliver the interrupt.
That's why this patch introduces a different way of masking/unmasking
the interrupts, simply by registering/unregistering the eventfd with the
GSI. This way, when the vector is masked, the eventfd is going to be
written but nothing will happen because KVM won't consume the event.
Whenever the unmask happens, the eventfd will be registered with a
specific GSI, and if there's some pending events, KVM will trigger them,
based on the route associated with the GSI.
Suggested-by: Liu Jiang <gerry@linux.alibaba.com>
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Having the InterruptManager trait depend on an InterruptType forces
implementations into supporting potentially very different kind of
interrupts from the same code base. What we're defining through the
current, interrupt type based create_group() method is a need for having
different interrupt managers for different kind of interrupts.
By associating the InterruptManager trait to an interrupt group
configuration type, we create a cleaner design to support that need as
we're basically saying that one interrupt manager should have the single
responsibility of supporting one kind of interrupt (defined through its
configuration).
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
We create 2 different interrupt managers for separately handling
creation of legacy and MSI interrupt groups.
Doing so allows us to have a cleaner interrupt manager and IOAPIC
initialization path. It also prepares for an InterruptManager trait
design improvement where we remove the interrupt source type dependency
by associating an interrupt configuration type to the trait.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
By introducing a new InterruptManager dedicated to the IOAPIC, we don't
have to solve the chicken and eggs problem about which of the
InterruptManager or the Ioapic should be created first. It's also
totally fine to have two interrupt manager instances as they both share
the same list of GSI routes and the same allocator.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Relying on the previous commits, the legacy interrupt implementation can
be completed. The IOAPIC handler is used to deliver the interrupt that
will be triggered through the trigger() method.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
By having a reference to the IOAPIC, the KvmInterruptManager is going
to be able to initialize properly the legacy interrupt source group.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In order to be able to use the InterruptManager abstraction with
virtio-mmio devices, this commit introduces InterruptSourceGroup's
skeleton for legacy interrupts.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
When KvmInterruptManager initializes a new InterruptSourceGroup, it's
only for PCI_MSI_IRQ case that it needs to allocate the GSI and create a
new InterruptRoute. That's why this commit moves the general code into
the specific use case.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
When the base InterruptIndex is different from 0, the loop allocating
GSI and HashMap entries won't work as expected. The for loop needs to
start from base, but the limit must be base+count so that we allocate
a number of "count" entries.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
After the skeleton of InterruptManager and InterruptSourceGroup traits
have been implemented, this new commit takes care of fully implementing
the content of KvmInterruptManager (InterruptManager trait) and
MsiInterruptGroup (InterruptSourceGroup).
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit introduces an empty implementation of both InterruptManager
and InterruptSourceGroup traits, as a proper basis for further
implementation.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
