From d0447fb719865f15b9f33e0eec2aabb8ca4bce47 Mon Sep 17 00:00:00 2001 From: Babis Chalios Date: Wed, 23 Oct 2024 11:54:39 +0200 Subject: [PATCH] doc: add CHANGELOG entry for KVM_KVMCLOCK_CTRL ioctl Mention that we now call KVM_KVMCLOCK_CTRL ioctl on x86_64 after pausing vCPUs. Clarify that failures to call this ioctl are not fatal and that we log the failure and increase a metric when these happen. Signed-off-by: Babis Chalios --- CHANGELOG.md | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/CHANGELOG.md b/CHANGELOG.md index f7f50678de4a..08f2582edfa1 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -14,6 +14,15 @@ and this project adheres to `VIRTIO_NET_F_RX_MRGBUF` support to the `virtio-net` device. When this feature is negotiated, guest `virtio-net` driver can perform more efficient memory management which in turn improves RX and TX performance. +- [#4460](https://github.com/firecracker-microvm/firecracker/pull/4460): Add a + call to + [`KVM_KVMCLOCK_CTRL`](https://docs.kernel.org/virt/kvm/api.html#kvm-kvmclock-ctrl) + after pausing vCPUs on x86_64 architectures. This ioctl sets a flag in the KVM + state of the vCPU indicating that it has been paused by the host userspace. In + guests that use kvmclock, the soft lockup watchdog checks this flag. If it is + set, it won't trigger the lockup condition. Calling the ioctl for guests that + don't use kvmclock will fail. These failures are not fatal; we log the failure + and increase the `vmm.kvmclock_ctrl_fails` metric. ### Changed