KVM: arm64: vgic: Make kvm_vgic_inject_irq() take a vcpu pointer

Passing a vcpu_id to kvm_vgic_inject_irq() is silly for two reasons:

- we often confuse vcpu_id and vcpu_idx
- we eventually have to convert it back to a vcpu
- we can't count

Instead, pass a vcpu pointer, which is unambiguous. A NULL vcpu
is also allowed for interrupts that are not private to a vcpu
(such as SPIs).

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

KVM: arm64: vgic: Add memcg accounting to vgic allocations

Inspired by commit 254272ce6505 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 vgic consistent with
common kvm codes.

The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.

There remain a few cases since these allocations are global, not in VM
scope.

Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210907123112.10232-2-justin.he@arm.com

KVM: arm64: Allow in-atomic injection of SPIs

On a system that uses SPIs to implement MSIs (as it would be
the case on a GICv2 system exposing a GICv2m to its guests),
we deny the possibility of injecting SPIs on the in-atomic
fast-path.

This results in a very large amount of context-switches
(roughly equivalent to twice the interrupt rate) on the host,
and suboptimal performance for the guest (as measured with
a test workload involving a virtio interface backed by vhost-net).
Given that GICv2 systems are usually on the low-end of the spectrum
performance wise, they could do without the aggravation.

We solved this for GICv3+ITS by having a translation cache. But
SPIs do not need any extra infrastructure, and can be immediately
injected in the virtual distributor as the locking is already
heavy enough that we don't need to worry about anything.

This halves the number of context switches for the same workload.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

KVM: arm64: Move virt/kvm/arm to arch/arm64

Now that the 32bit KVM/arm host is a distant memory, let's move the
whole of the KVM/arm64 code into the arm64 tree.

As they said in the song: Welcome Home (Sanitarium).

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200513104034.74741-1-maz@kernel.org