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8aeb879baf
It was missed that idt_do_interrupt_irqoff() gets compiled on x84_64;
this is a problem for CFI builds because it includes an unadorned
indirect call. It is however completely dead code.
Rework things to not emit this function at all.
Fixes: 0701c9e17b ("x86/kvm/vmx: Move IRQ/NMI dispatch from KVM into x86 core")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260526090631.GA4149641@noisy.programming.kicks-ass.net
62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/entry-common.h>
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#include <linux/kvm_types.h>
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#include <linux/hrtimer_rearm.h>
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#include <asm/fred.h>
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#include <asm/desc.h>
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#if IS_ENABLED(CONFIG_KVM_INTEL)
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/*
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* On VMX, NMIs and IRQs (as configured by KVM) are acknowledged by hardware as
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* part of the VM-Exit, i.e. the event itself is consumed as part the VM-Exit.
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* x86_entry_from_kvm() is invoked by KVM to effectively forward NMIs and IRQs
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* to the kernel for servicing. On SVM, a.k.a. AMD, the NMI/IRQ VM-Exit is
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* purely a signal that an NMI/IRQ is pending, i.e. the event that triggered
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* the VM-Exit is held pending until it's unblocked in the host.
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*/
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noinstr void x86_entry_from_kvm(unsigned int event_type, unsigned int vector)
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{
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if (event_type == EVENT_TYPE_EXTINT) {
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#ifdef CONFIG_X86_64
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/*
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* Use FRED dispatch, even when running IDT. The dispatch
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* tables are kept in sync between FRED and IDT, and the FRED
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* dispatch works well with CFI.
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*/
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fred_entry_from_kvm(event_type, vector);
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#else
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idt_entry_from_kvm(vector);
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#endif
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/*
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* Strictly speaking, only the NMI path requires noinstr.
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*/
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instrumentation_begin();
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/*
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* KVM/VMX will dispatch from IRQ-disabled but for a context
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* that will have IRQs-enabled. This confuses the entry code
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* and it will not have reprogrammed the timer. Do so now.
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*/
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hrtimer_rearm_deferred();
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instrumentation_end();
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return;
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}
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WARN_ON_ONCE(event_type != EVENT_TYPE_NMI);
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#ifdef CONFIG_X86_64
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if (cpu_feature_enabled(X86_FEATURE_FRED))
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return fred_entry_from_kvm(event_type, vector);
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#endif
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/*
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* Notably, we must use IDT dispatch for NMI when running in IDT mode.
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* The FRED NMI context is significantly different and will not work
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* right (specifically FRED fixed the NMI recursion issue).
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*/
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idt_do_nmi_irqoff();
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}
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EXPORT_SYMBOL_FOR_KVM(x86_entry_from_kvm);
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#endif
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