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/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/entry-common.h>
#include <linux/kvm_types.h>
#include <linux/hrtimer_rearm.h>
#include <asm/fred.h>
#include <asm/desc.h>
#if IS_ENABLED(CONFIG_KVM_INTEL)
/*
* On VMX, NMIs and IRQs (as configured by KVM) are acknowledged by hardware as
* part of the VM-Exit, i.e. the event itself is consumed as part the VM-Exit.
* x86_entry_from_kvm() is invoked by KVM to effectively forward NMIs and IRQs
* to the kernel for servicing. On SVM, a.k.a. AMD, the NMI/IRQ VM-Exit is
* purely a signal that an NMI/IRQ is pending, i.e. the event that triggered
* the VM-Exit is held pending until it's unblocked in the host.
*/
noinstr void x86_entry_from_kvm(unsigned int event_type, unsigned int vector)
{
if (event_type == EVENT_TYPE_EXTINT) {
#ifdef CONFIG_X86_64
/*
* Use FRED dispatch, even when running IDT. The dispatch
* tables are kept in sync between FRED and IDT, and the FRED
* dispatch works well with CFI.
*/
fred_entry_from_kvm(event_type, vector);
#else
idt_entry_from_kvm(vector);
#endif
/*
* Strictly speaking, only the NMI path requires noinstr.
*/
instrumentation_begin();
/*
* KVM/VMX will dispatch from IRQ-disabled but for a context
* that will have IRQs-enabled. This confuses the entry code
* and it will not have reprogrammed the timer. Do so now.
*/
hrtimer_rearm_deferred();
instrumentation_end();
return;
}
WARN_ON_ONCE(event_type != EVENT_TYPE_NMI);
#ifdef CONFIG_X86_64
if (cpu_feature_enabled(X86_FEATURE_FRED))
return fred_entry_from_kvm(event_type, vector);
#endif
/*
* Notably, we must use IDT dispatch for NMI when running in IDT mode.
* The FRED NMI context is significantly different and will not work
* right (specifically FRED fixed the NMI recursion issue).
*/
idt_do_nmi_irqoff();
}
EXPORT_SYMBOL_FOR_KVM(x86_entry_from_kvm);
#endif
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