github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-06 21:58:01 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: arm64: vgic-its: Remove the pending state of a discarded LPI

Browse Source 
DISCARD removes the mapping of an event and instructs the Redistributor
to remove the pending state of its LPI (IHI 0069H.b, 5.3.4). KVM only
frees the ITE, so an LPI that is pending when the guest discards it
stays queued on its target vCPU, and the guest still takes it.

Clear the pending state before freeing the ITE. A queued LPI can be
pending in a running vCPU's list register, so halt the guest first when
the LPI is queued, to fold that state back. A forwarded LPI already
loses its pending state in its_free_ite(), whose unmap from the vPE
sends a DISCARD to the host ITS.

[maz: folded-in rework to only pause the involved vcpus]

Fixes: df9f58fbea ("KVM: arm64: vgic-its: Implement ITS command queue command handlers")
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20261013081646.933312-3-fuad.tabba@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Fuad Tabba 2026-10-13 09:16:46 +01:00 committed by Marc Zyngier
parent de81b28f0b
commit e99ff76f4a
1 changed files with 28 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
arch/arm64/kvm/vgic/vgic-its.c
View File

@ -833,13 +833,36 @@ static int vgic_its_cmd_handle_discard(struct kvm *kvm, struct vgic_its *its,
struct its_device *device = find_its_device(its, device_id);
int ite_esz = vgic_its_get_abi(its)->ite_esz;
gpa_t gpa = device->itt_addr + ite->event_id * ite_esz;
/*
* Though the spec talks about removing the pending state, we
* don't bother here since we clear the ITTE anyway and the
* pending state is a property of the ITTE struct.
*/
struct vgic_irq *irq = ite->irq;
struct kvm_vcpu *vcpu, *target;
vgic_its_invalidate_cache(its);
/*
* Only an LPI on a vCPU's AP list can be in its list registers,
* which the exit path folds back, and that exit moves the LPI
* to its target vCPU if the target has changed: pause both.
*/
scoped_guard(raw_spinlock_irqsave, &irq->irq_lock) {
vcpu = irq->vcpu;
target = irq->target_vcpu;
}
if (vcpu) {
if (target != vcpu)
kvm_pause_vcpu(target);
kvm_pause_vcpu(vcpu);
}
scoped_guard(raw_spinlock_irqsave, &irq->irq_lock)
irq->pending_latch = false;
if (vcpu) {
kvm_resume_vcpu(vcpu);
if (target != vcpu)
kvm_resume_vcpu(target);
}
its_free_ite(kvm, ite);
return vgic_its_write_entry_lock(its, gpa, 0ULL, ite);