diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-07-21 13:18:45 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-03 15:37:14 -0700 |
| commit | ad93c1a7c0102c93e92bf0c06412a1f588e015ab (patch) | |
| tree | 7d804b9c95e78721f91bf669125ccc96252597fd | |
| parent | baeb4de7ad12b700a91f2a7be8e1c0389a5c8fd4 (diff) | |
x86/reboot: Assert that IRQs are disabled when turning off virtualization
Assert that IRQs are disabled when turning off virtualization in an
emergency. KVM enables hardware via on_each_cpu(), i.e. could re-enable
hardware if a pending IPI were delivered after disabling virtualization.
Remove a misleading comment from emergency_reboot_disable_virtualization()
about "just" needing to guarantee the CPU is stable (see above).
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kernel/reboot.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 48ad2d1ff83d..4cad7183b89e 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -532,7 +532,6 @@ static inline void nmi_shootdown_cpus_on_restart(void); static void emergency_reboot_disable_virtualization(void) { - /* Just make sure we won't change CPUs while doing this */ local_irq_disable(); /* @@ -821,6 +820,13 @@ void cpu_emergency_disable_virtualization(void) { cpu_emergency_virt_cb *callback; + /* + * IRQs must be disabled as KVM enables virtualization in hardware via + * function call IPIs, i.e. IRQs need to be disabled to guarantee + * virtualization stays disabled. + */ + lockdep_assert_irqs_disabled(); + rcu_read_lock(); callback = rcu_dereference(cpu_emergency_virt_callback); if (callback) |