Looking up devices on the port I/O bus is time consuming during the
boot at there is an O(lg n) tree lookup and the overhead from taking a
lock on the bus contents.
Avoid this by adding a fast path uses the hardcoded port address and
size and directs PCI config requests directly to the device.
Command line:
target/release/cloud-hypervisor --kernel ~/src/linux/vmlinux --cmdline "root=/dev/vda1 console=ttyS0" --serial tty --console off --disk path=~/workloads/focal-server-cloudimg-amd64-custom-20210609-0.raw --api-socket /tmp/api
PIO exit: 17913
PCI fast path: 17871
Percentage on fast path: 99.8%
perf before:
marvin:~/src/cloud-hypervisor (main *)$ perf report -g | grep resolve
6.20% 6.20% vcpu0 cloud-hypervisor [.] vm_device:🚌:Bus::resolve
perf after:
marvin:~/src/cloud-hypervisor (2021-09-17-ioapic-fast-path *)$ perf report -g | grep resolve
0.08% 0.08% vcpu0 cloud-hypervisor [.] vm_device:🚌:Bus::resolve
The compromise required to implement this fast path is bringing the
creation of the PciConfigIo device into the DeviceManager::new() so that
it can be used in the VmmOps struct which is created before
DeviceManager::create_devices() is called.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Added a section in "Usage" chapter of "iommu.md" to introduce the
special behavior when virtio-iommu is working with FDT on AArch64.
Signed-off-by: Michael Zhao <michael.zhao@arm.com>
For AArch64, now virtual IOMMU is only tested on FDT, not ACPI.
In the case of FDT, the behavior of IOMMU is a bit different with ACPI.
All the devices on the PCI bus will be attached to the virtual IOMMU,
except the virtio-iommu device itself. So these devices will all be
added to IOMMU groups, and appear in folder '/sys/kernel/iommu_groups/'.
The result is, on AArch64 IOMMU group '0' contains "0000:00:01.0" which
is the console device. But on X86, console device is not attached to
IOMMU. So the IOMMU group '0' contains "0000:00:02.0" which is the first
disk.
Signed-off-by: Michael Zhao <michael.zhao@arm.com>
The MSI IOVA address on X86 and AArch64 is different.
This commit refactored the code to receive the MSI IOVA address and size
from device_manager, which provides the actual IOVA space data for both
architectures.
Signed-off-by: Michael Zhao <michael.zhao@arm.com>
Move the definition of MSI space to layout.rs, so other crates can
reference it. Now it is needed by virtio-iommu.
Signed-off-by: Michael Zhao <michael.zhao@arm.com>
Add a virtio-iommu node into FDT if iommu option is turned on. Now we
support only one virtio-iommu device.
Signed-off-by: Michael Zhao <michael.zhao@arm.com>
This change switches from handling serial input in the VMM thread to
its own thread controlled by the SerialManager.
The motivation for this change is to avoid the VMM thread being unable
to process events while serial input is happening and vice versa.
The change also makes future work flushing the serial buffer on PTY
connections easier.
Signed-off-by: William Douglas <william.douglas@intel.com>
This change adds a SerialManager with its own epoll handling that
should be created and run by the DeviceManager when creating an
appropriately configured console (serial tty or pty).
Both stdin and pty input are handled by the SerialManager. The stdin
and pty specific methods used by the VMM should be removed in a future
commit.
Signed-off-by: William Douglas <william.douglas@intel.com>
The clone method for PtyPair should have been an impl of the Clone
trait but the method ended up not being used. Future work will make
use of the trait however so correct the missing trait implementation.
Signed-off-by: William Douglas <william.douglas@intel.com>
libc::getrandom need to be called inside unsafe and it is not
cross-platform friendly.
Change it to getrandom::getrandom that is safe and cross-platform
friendly.
Signed-off-by: Hui Zhu <teawater@antfin.com>
Updating kvm-ioctls from 0.9.0 to 0.10.0 now that Cloud Hypervisor
relies on kvm-bindings 0.5.0.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
For most use cases, there is no need to create multiple VFIO containers
as it causes unwanted behaviors. Especially when passing multiple
devices from the same IOMMU group, we need to use the same container so
that it can properly list the groups that have been already opened. The
correct logic was already there in vfio-ioctls, but it was incorrectly
used from our VMM implementation.
For the special case where we put a VFIO device behind a vIOMMU, we must
create one container per device, as we need to control the DMA mappings
per device, which is performed at the container level. Because we must
keep one container per device, the vIOMMU use case prevents multiple
devices attached to the same IOMMU group to be passed through the VM.
But this is a limitation that we are fine with, especially since the
vIOMMU doesn't let us group multiple devices in the same group from a
guest perspective.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This allows Cloud Hypervisor to be run under `perf` as some of the
signals will already be blocked in the child process.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Update the kvm-bindings dependency so that Cloud Hypervisor now depends
on the version 0.5.0, which is based on Linux kernel v5.13.0. We still
have to rely on a forked version to be able to serialize all the KVM
structures we need.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Validate the size of I/O reads and check that no request is made to an
out of bounds index (which would cause a panic.)
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Check the size of data buffer for reading on the ApciPmTimer device to
avoid a potential panic if the guest uses non-DWORD access.
Simplify the zeroring of the buffer for AcpiShutdownDevice.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
When a pty is resized (using the TIOCSWINSZ ioctl -- see ioctl_tty(2)),
the kernel will send a SIGWINCH signal to the pty's foreground process
group to notify it of the resize. This is the only way to be notified
by the kernel of a pty resize.
We can't just make the cloud-hypervisor process's process group the
foreground process group though, because a process can only set the
foreground process group of its controlling terminal, and
cloud-hypervisor's controlling terminal will often be the terminal the
user is running it in. To work around this, we fork a subprocess in a
new process group, and set its process group to be the foreground
process group of the pty. The subprocess additionally must be running
in a new session so that it can have a different controlling
terminal. This subprocess writes a byte to a pipe every time the pty
is resized, and the virtio-console device can listen for this in its
epoll loop.
Alternatives I considered were to have the subprocess just send
SIGWINCH to its parent, and to use an eventfd instead of a pipe.
I decided against the signal approach because re-purposing a signal
that has a very specific meaning (even if this use was only slightly
different to its normal meaning) felt unclean, and because it would
have required using pidfds to avoid race conditions if
cloud-hypervisor had terminated, which added complexity. I decided
against using an eventfd because using a pipe instead allows the child
to be notified (via poll(2)) when nothing is reading from the pipe any
more, meaning it can be reliably notified of parent death and
terminate itself immediately.
I used clone3(2) instead of fork(2) because without
CLONE_CLEAR_SIGHAND the subprocess would inherit signal-hook's signal
handlers, and there's no other straightforward way to restore all signal
handlers to their defaults in the child process. The only way to do
it would be to iterate through all possible signals, or maintain a
global list of monitored signals ourselves (vmm:vm::HANDLED_SIGNALS is
insufficient because it doesn't take into account e.g. the SIGSYS
signal handler that catches seccomp violations).
Signed-off-by: Alyssa Ross <hi@alyssa.is>
This prepares us to be able to handle console resizes in the console
device's epoll loop, which we'll have to do if the output is a pty,
since we won't get SIGWINCH from it.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Musl often uses mmap to allocate memory where Glibc would use brk.
This has caused seccomp violations for me on the API and signal
handling threads.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
As well as reducing the amount of code this also improves the binary
size slightly:
cargo bloat --release -n 2000 --bin cloud-hypervisor | grep virtio_devices::seccomp_filters::get_seccomp_rules
Before:
0.1% 0.2% 7.8KiB virtio_devices virtio_devices::seccomp_filters::get_seccomp_rules
After:
0.0% 0.1% 3.0KiB virtio_devices virtio_devices::seccomp_filters::get_seccomp_rules
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This patch adds a separate function to launch two guest VMs and ensure
they are connected through ovs-dpdk, so that we can reuse this function
in other tests, e.g. the test for live-migration with ovs-dpdk.
Signed-off-by: Bo Chen <chen.bo@intel.com>
error: all if blocks contain the same code at the end
--> vmm/src/memory_manager.rs:884:9
|
884 | / Ok(mm)
885 | | }
| |_________^
Signed-off-by: Bo Chen <chen.bo@intel.com>
This concept ends up being broken with multiple types on input connected
e.g. console on TTY and serial on PTY. Already the code for checking for
injecting into the serial device checks that the serial is configured.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
