Commit 45b00f41 authored by Wanpeng Li's avatar Wanpeng Li Committed by Zeng Heng
Browse files

KVM: LAPIC: Also cancel preemption timer during SET_LAPIC

mainline inclusion
from mainline-v5.17-rc2
commit 35fe7cfb
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA72K9
CVE: CVE-2022-48765

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=35fe7cfbab2e81f1afb23fc4212210b1de6d9633



--------------------------------

The below warning is splatting during guest reboot.

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1931 at arch/x86/kvm/x86.c:10322 kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm]
  CPU: 0 PID: 1931 Comm: qemu-system-x86 Tainted: G          I       5.17.0-rc1+ #5
  RIP: 0010:kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm]
  Call Trace:
   <TASK>
   kvm_vcpu_ioctl+0x279/0x710 [kvm]
   __x64_sys_ioctl+0x83/0xb0
   do_syscall_64+0x3b/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  RIP: 0033:0x7fd39797350b

This can be triggered by not exposing tsc-deadline mode and doing a reboot in
the guest. The lapic_shutdown() function which is called in sys_reboot path
will not disarm the flying timer, it just masks LVTT. lapic_shutdown() clears
APIC state w/ LVT_MASKED 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 apic_update_lvtt(). 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 KVM_SET_LAPIC.

Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Message-Id: <1643102220-35667-1-git-send-email-wanpengli@tencent.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Conflicts:
	arch/x86/kvm/lapic.c
[Resolve conflicts due to several refactor patches not merged.]
Signed-off-by: default avatarZeng Heng <zengheng4@huawei.com>
parent 1de0304d
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+1 −1
Original line number Diff line number Diff line
@@ -2623,7 +2623,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
	kvm_apic_set_version(vcpu);

	apic_update_ppr(apic);
	hrtimer_cancel(&apic->lapic_timer.timer);
	cancel_apic_timer(apic);
	apic_update_lvtt(apic);
	apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));
	update_divide_count(apic);