diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-07-21 13:18:41 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-03 15:37:14 -0700 |
| commit | b23c83ad2c638420ec0608a9de354507c41bec29 (patch) | |
| tree | 0b0778d125d3736404f549553574a2f52a42a4a4 /arch/x86/kernel/reboot.c | |
| parent | 41e90a69a49be2e3467e811ae8fdc17456af1b02 (diff) | |
x86/reboot: VMCLEAR active VMCSes before emergency reboot
VMCLEAR active VMCSes before any emergency reboot, not just if the kernel
may kexec into a new kernel after a crash. Per Intel's SDM, the VMX
architecture doesn't require the CPU to flush the VMCS cache on INIT. If
an emergency reboot doesn't RESET CPUs, cached VMCSes could theoretically
be kept and only be written back to memory after the new kernel is booted,
i.e. could effectively corrupt memory after reboot.
Opportunistically remove the setting of the global pointer to NULL to make
checkpatch happy.
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kernel/reboot.c')
| -rw-r--r-- | arch/x86/kernel/reboot.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 3adbe97015c1..3fa4c6717a1d 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -787,6 +787,26 @@ void machine_crash_shutdown(struct pt_regs *regs) } #endif +/* + * This is used to VMCLEAR all VMCSs loaded on the + * processor. And when loading kvm_intel module, the + * callback function pointer will be assigned. + * + * protected by rcu. + */ +crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss; +EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); + +static inline void cpu_crash_vmclear_loaded_vmcss(void) +{ + crash_vmclear_fn *do_vmclear_operation = NULL; + + rcu_read_lock(); + do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); + if (do_vmclear_operation) + do_vmclear_operation(); + rcu_read_unlock(); +} /* This is the CPU performing the emergency shutdown work. */ int crashing_cpu = -1; @@ -798,6 +818,8 @@ int crashing_cpu = -1; */ void cpu_emergency_disable_virtualization(void) { + cpu_crash_vmclear_loaded_vmcss(); + cpu_emergency_vmxoff(); cpu_emergency_svm_disable(); } |