Refactor VirtIO devices, preparing for a PCI transport layer #5160
+899
−470
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## feature/pcie #5160 +/- ##
==============================================
Coverage 83.06% 83.07%
==============================================
Files 250 251 +1
Lines 26897 27033 +136
==============================================
+ Hits 22342 22457 +115
- Misses 4555 4576 +21
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
bchalios
force-pushed
the
feature/pcie
branch
7 times, most recently
from
7ab92d6 to
5dd5953
Compare
ShadowCurse
reviewed
Apr 22, 2025
Manciukic
reviewed
Apr 22, 2025
bchalios
force-pushed
the
feature/pcie
branch
2 times, most recently
from
040a2e2 to
9880eac
Compare
roypat
reviewed
Apr 23, 2025
bchalios
force-pushed
the
feature/pcie
branch
5 times, most recently
from
c59d619 to
e21d2f7
Compare
bchalios
added
the
Status: Awaiting review
|
I checked the codecov failures. All reported unchecked lines of code were already existing. It's not new code. |
bchalios
changed the title
roypat
reviewed
Apr 29, 2025
bchalios
force-pushed
the
feature/pcie
branch
3 times, most recently
from
023ad6e to
dc41d9e
Compare
ShadowCurse
reviewed
Apr 29, 2025
bchalios
force-pushed
the
feature/pcie
branch
2 times, most recently
from
aa74281 to
7ff5c60
Compare
This is just code organization changes. Create a new module under `virtio`, called `transport`. For the time being the only transport supported is `mmio`. Also, move `IrqInterrupt` type within the MMIO transport code, as it is MMIO specific. Signed-off-by: Babis Chalios <bchalios@amazon.es>
`IrqTrigger::new()` returns a `Result` because creating an `EventFd` might fail with an `std::io::Error` error. All users of `IrqTrigger` create the object and directly unwrap the error. To avoid unwraps all over the place, change `IrqTrigger::new()` to unwrap a potential error while creating the EventFd internally and just return `Self`. Signed-off-by: Babis Chalios <bchalios@amazon.es>
The MMIO transport for VirtIO devices uses an `IrqTrigger` object as the object that models the logic for sending interrupts from the device to the guest. We create one such object for every VirtIO device when creating it. The MMIO device manager associates this object with an IRQ number and registers it with KVM. This commit changes the timing of association of an `IrqTrigger` with a VirtIO-mmio device. It only assigns such an object to the device during its activation. We do this to prepare for supporting a PCI transport for VirtIO devices. The cloud hypervisor implementation for these passes the interrupt objects used by the device during activation, so we make this change to have a uniform way to handle interrupts for both transports. Functionally, nothing changes for MMIO devices, as before activation we don't trigger any interrupts. Signed-off-by: Babis Chalios <bchalios@amazon.es>
Describing the APIs that need to implement types that are used as interrupts for VirtIO devices. Currently, we only use `IrqInterrupt` interrupts, but this will change once we have MSI-X with PCIe devices. Signed-off-by: Babis Chalios <bchalios@amazon.es>
VirtIO devices assume they're operating under an MMIO transport and as a consequence they use IrqTrigger as interrupts. Switch that to using VirtioInterrupt for all VirtIO device objects. Only assume a VirtioInterrupt is an IrqTrigger in MMIO specific code. Signed-off-by: Babis Chalios <bchalios@amazon.es>
ShadowCurse
approved these changes
Apr 30, 2025
roypat
approved these changes
Apr 30, 2025
bchalios
merged commit 87a7164
into
firecracker-microvm:feature/pcie
5 of 7 checks passed
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Changes
This does a few changes around interrupts for VirtIO devices and code organization for being able to handle multiple transports for VirtIO devices:
transportmodule withinvmm::devices::virtioand movesmmiomodule inside itVirtioInterrupttrait that abstracts away the functionality of interrupts used by VirtIO devices. At the moment, onlyIrqTriggerimplementsVirtioInterrupt.IrqTriggerobject is assigned to a VirtIO device. Up until now we created this object when creating the device itself. This PR changes this logic so that it is the transport layer that creates this interrupt and passes it over to the device during activation time. This is how things are done with PCIe in the Cloud Hypervisor implementation. It also, doesn't change anything for us, semantically; devices only trigger interrupts after having been activated.Reason
Preparing for adding PCIe support
License Acceptance
By submitting this pull request, I confirm that my contribution is made under
the terms of the Apache 2.0 license. For more information on following Developer
Certificate of Origin and signing off your commits, please check
CONTRIBUTING.md.PR Checklist
tools/devtool checkstyleto verify that the PR passes theautomated style checks.
how they are solving the problem in a clear and encompassing way.
in the PR.
CHANGELOG.md.Runbook for Firecracker API changes.
integration tests.
TODO.rust-vmm.