CVE-2022-48765

In the Linux kernel, the following vulnerability has been resolved:

KVM: LAPIC: Also cancel preemption timer during SET_LAPIC

The below warning is splatting during guest reboot.

------------[ cut here ]------------ WARNING: CPU: 0 PID: 1931 at arch/x86/kvm/x86.c:10322 kvmarchvcpuioctlrun+0x874/0x880 [kvm] CPU: 0 PID: 1931 Comm: qemu-system-x86 Tainted: G I 5.17.0-rc1+ #5 RIP: 0010:kvmarchvcpuioctlrun+0x874/0x880 [kvm] Call Trace: <TASK> kvmvcpuioctl+0x279/0x710 [kvm] __x64sysioctl+0x83/0xb0 dosyscall64+0x3b/0xc0 entrySYSCALL64afterhwframe+0x44/0xae RIP: 0033:0x7fd39797350b

This can be triggered by not exposing tsc-deadline mode and doing a reboot in the guest. The lapicshutdown() function which is called in sysreboot path will not disarm the flying timer, it just masks LVTT. lapicshutdown() clears APIC state w/ LVTMASKED and timer-mode bit is 0, this can trigger timer-mode switch between tsc-deadline and oneshot/periodic, which can result in preemption timer be cancelled in apicupdatelvtt(). However, We can't depend on this when not exposing tsc-deadline mode and oneshot/periodic modes emulated by preemption timer. Qemu will synchronise states around reset, let's cancel preemption timer under KVMSETLAPIC.