The following are the notable fixes and improvements that have been made in this update:

• Fix to remove inappropriate warning messages

  A minor fix was applied for an issue that generated an innocuous warning message on a host running Oracle Linux 7 Update 4 and using libvirt or virtmanager to create a QEMU guest. The code that generated the issue has been updated to only print when debugging is enabled.

• pvclock-page value handling issue resolved

  An issue that triggered when a guest passes KVM its pvclock-page GPA for the first time is resolved to follow standard logic applied to other pvclock shared pages, preventing the page from initializing with an incorrect random value that could cause a system hang.

• Upstream patches applied for better checks on VM Exit pending events

  Upstream patches were applied to resolve a blocking error that could trigger when an event was re-injected to L2 and that could cause an L2 guest to exit to L1 even when there was no pending L1 event. The fix adds addition checks for pending events and returns -EBUSY if there is one.

• Security fixes for retpoline support

  Security fixes have been implemented to mitigate against kernel or cross-process memory disclosure such as the attack vector used by Spectre V2. A backport was introduced to fix an issue that resulted in the use of a stale MSR value generated by a previous VM exit where retpoline support is enabled in the host kernel. This issue directly affected KVM.