diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-05-28 16:13:52 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-18 15:47:01 +0200 |
| commit | 6758034e4d6a7f0e26b748789ab1f83f3116d1b9 (patch) | |
| tree | fcaaccf48964fa4f0a63bf54ccb1b9ec3d902fd7 /arch/x86/kernel/process_64.c | |
| parent | 58edfd2e0a93c9adc2f29902a0335af0584041a0 (diff) | |
x86/process/64: Make save_fsgs_for_kvm() ready for FSGSBASE
save_fsgs_for_kvm() is invoked via
vcpu_enter_guest()
kvm_x86_ops.prepare_guest_switch(vcpu)
vmx_prepare_switch_to_guest()
save_fsgs_for_kvm()
with preemption disabled, but interrupts enabled.
The upcoming FSGSBASE based GS safe needs interrupts to be disabled. This
could be done in the helper function, but that function is also called from
switch_to() which has interrupts disabled already.
Disable interrupts inside save_fsgs_for_kvm() and rename the function to
current_save_fsgs() so it can be invoked from other places.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528201402.1708239-7-sashal@kernel.org
Diffstat (limited to 'arch/x86/kernel/process_64.c')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index c41e0aae8426..ef2f75588f41 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -240,18 +240,21 @@ static __always_inline void save_fsgs(struct task_struct *task) save_base_legacy(task, task->thread.gsindex, GS); } -#if IS_ENABLED(CONFIG_KVM) /* * While a process is running,current->thread.fsbase and current->thread.gsbase - * may not match the corresponding CPU registers (see save_base_legacy()). KVM - * wants an efficient way to save and restore FSBASE and GSBASE. - * When FSGSBASE extensions are enabled, this will have to use RD{FS,GS}BASE. + * may not match the corresponding CPU registers (see save_base_legacy()). */ -void save_fsgs_for_kvm(void) +void current_save_fsgs(void) { + unsigned long flags; + + /* Interrupts need to be off for FSGSBASE */ + local_irq_save(flags); save_fsgs(current); + local_irq_restore(flags); } -EXPORT_SYMBOL_GPL(save_fsgs_for_kvm); +#if IS_ENABLED(CONFIG_KVM) +EXPORT_SYMBOL_GPL(current_save_fsgs); #endif static __always_inline void loadseg(enum which_selector which, |