kernel/arch/x86/kvm/irq.c, branch linux-rolling-lts

KVM: x86: Export KVM-internal symbols for sub-modules only

2025-09-30T17:40:02Z

Rework almost all of KVM x86's exports to expose symbols only to KVM's vendor modules, i.e. to kvm-{amd,intel}.ko. Keep the generic exports that are guarded by CONFIG_KVM_EXTERNAL_WRITE_TRACKING=y, as they're explicitly designed/intended for external usage. Link: https://lore.kernel.org/r/20250919003303.1355064-6-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini

KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c

2025-09-30T17:40:02Z

Move kvm_intr_is_single_vcpu() to lapic.c, drop its export, and make its "fast" helper local to lapic.c. kvm_intr_is_single_vcpu() is only usable if the local APIC is in-kernel, i.e. it most definitely belongs in the local APIC code. No functional change intended. Fixes: cf04ec393ed0 ("KVM: x86: Dedup AVIC vs. PI code for identifying target vCPU") Link: https://lore.kernel.org/r/20250919003303.1355064-4-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini

KVM: x86: Move kvm_irq_delivery_to_apic() from irq.c to lapic.c

2025-09-10T19:05:09Z

Move kvm_irq_delivery_to_apic() to lapic.c as it is specific to local APIC emulation. This will allow burying more local APIC code in lapic.c, e.g. the various "lowest priority" helpers. No functional change intended. Link: https://lore.kernel.org/r/20250821214209.3463350-2-seanjc@google.com Signed-off-by: Sean Christopherson

Revert "kvm: detect assigned device via irqbypass manager"

2025-06-25T16:51:29Z

Now that KVM explicitly tracks the number of possible bypass IRQs, and doesn't conflate IRQ bypass with host MMIO access, stop bumping the assigned device count when adding an IRQ bypass producer. This reverts commit 2edd9cb79fb31b0907c6e0cdce2824780cf9b153. Link: https://lore.kernel.org/r/20250523011756.3243624-5-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: Rename kvm_set_msi_irq() => kvm_msi_to_lapic_irq()

2025-06-23T16:50:53Z

Rename kvm_set_msi_irq() to kvm_msi_to_lapic_irq() to better capture what it actually does, e.g. it's _really_ easy to conflate kvm_set_msi_irq() with kvm_set_msi(). Opportunistically delete the public declaration and export, as they are no longer used/needed. No functional change intended. Link: https://lore.kernel.org/r/20250611224604.313496-64-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: Decouple device assignment from IRQ bypass

2025-06-23T16:50:46Z

Use a dedicated counter to track the number of IRQs that can utilize IRQ bypass instead of piggybacking the assigned device count. As evidenced by commit 2edd9cb79fb3 ("kvm: detect assigned device via irqbypass manager"), it's possible for a device to be able to post IRQs to a vCPU without said device being assigned to a VM. Leave the calls to kvm_arch_{start,end}_assignment() alone for the moment to avoid regressing the MMIO stale data mitigation. KVM is abusing the assigned device count when applying mmio_stale_data_clear, and it's not at all clear if vDPA devices rely on this behavior. This will hopefully be cleaned up in the future, as the number of assigned devices is a terrible heuristic for detecting if a VM has access to host MMIO. Link: https://lore.kernel.org/r/20250611224604.313496-55-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: WARN if IRQ bypass routing is updated without in-kernel local APIC

2025-06-23T16:50:45Z

Yell if kvm_pi_update_irte() is reached without an in-kernel local APIC, as kvm_arch_irqfd_allowed() should prevent attaching an irqfd and thus any and all postable IRQs to an APIC-less VM. Link: https://lore.kernel.org/r/20250611224604.313496-53-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: WARN if IRQ bypass isn't supported in kvm_pi_update_irte()

2025-06-23T16:50:44Z

WARN if kvm_pi_update_irte() is reached without IRQ bypass support, as the code is only reachable if the VM already has an IRQ bypass producer (see kvm_irq_routing_update()), or from kvm_arch_irq_bypass_{add,del}_producer(), which, stating the obvious, are called if and only if KVM enables its IRQ bypass hooks. Cc: David Matlack Link: https://lore.kernel.org/r/20250611224604.313496-52-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: Drop superfluous "has assigned device" check in kvm_pi_update_irte()

2025-06-23T16:50:44Z

Don't bother checking if the VM has an assigned device when updating IRTE entries. kvm_arch_irq_bypass_add_producer() explicitly increments the assigned device count, kvm_arch_irq_bypass_del_producer() explicitly decrements the count before invoking kvm_pi_update_irte(), and kvm_irq_routing_update() only updates IRTE entries if there's an active IRQ bypass producer. Link: https://lore.kernel.org/r/20250611224604.313496-51-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: x86: Don't update IRTE entries when old and new routes were !MSI

2025-06-23T16:50:35Z

Skip the entirety of IRTE updates on a GSI routing change if neither the old nor the new routing is for an MSI, i.e. if the neither routing setup allows for posting to a vCPU. If the IRTE isn't already host controlled, KVM has bigger problems. Link: https://lore.kernel.org/r/20250611224604.313496-38-seanjc@google.com Signed-off-by: Sean Christopherson