In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Ignore pending PV EOI if the vCPU has since disabled PV EOIs Ignore KVM's internal "service pending PV EOI" request if the vCPU has disabled PV EOIs since the request was made. Asserting that PV EOIs are enabled can fail if reading guest memory in pv_eoi_get_user() fails, i.e. if pv_eoi_test_and_clr_pending() bails early, *and* the vCPU also disables PV EOIs. kernel BUG at arch/x86/kvm/lapic.c:3338! Oops: invalid opcode: 0000 [#1] SMP CPU: 4 UID: 1000 PID: 890 Comm: pv_eoi_test Not tainted 7.0.0-d585aa5894d8-vm #337 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kvm_lapic_sync_from_vapic+0x12b/0x140 [kvm] Call Trace: <TASK> kvm_arch_vcpu_ioctl_run+0x1075/0x1c30 [kvm] kvm_vcpu_ioctl+0x2d5/0x980 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb5/0xb40 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> Modules linked in: kvm_intel kvm irqbypass ---[ end trace 0000000000000000 ]---
https://git.kernel.org/stable/c/ebd7845ca0471d251a1cb48d84eb165aff5b7123
https://git.kernel.org/stable/c/97542f15dc4cf6cd3fdc035e482dca54246ddf48
https://git.kernel.org/stable/c/9285e4070df2c40585c3d7ec9571faa7a2b97e17
https://git.kernel.org/stable/c/8e9f7a95279bf608cf4c331ed89612e28c04564f
https://git.kernel.org/stable/c/32bdca80aa81c2cb906f50a88b220ce1ecdc5e6e
https://git.kernel.org/stable/c/038b9ce6fafda1babd1e33d52cbc6039747a6d87