x86/reboot: Harden virtualization hooks for emergency reboot

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Provide dedicated helpers to (un)register virt hooks used during an
emergency crash/reboot, and WARN if there is an attempt to overwrite
the registered callback, or an attempt to do an unpaired unregister.

Opportunsitically use rcu_assign_pointer() instead of RCU_INIT_POINTER(),
mainly so that the set/unset paths are more symmetrical, but also because
any performance gains from using RCU_INIT_POINTER() are meaningless for
this code.

Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Sean Christopherson 2023-07-21 13:18:42 -07:00

parent b23c83ad2c

commit 5e408396c6

3 changed files with 29 additions and 12 deletions

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5

arch/x86/include/asm/reboot.h

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30

arch/x86/kernel/reboot.c

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6

arch/x86/kvm/vmx/vmx.c

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