Hi Eric,
just fast-forwarded to the end and noticed this one:
On 06/03/17 11:34, Eric Auger wrote:
> Save and restore the pending tables.
>
> Pending table restore obviously requires the pendbaser to be
> already set.
>
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>
> ---
>
> v1 -> v2:
> - do not care about the 1st KB which should be zeroed according to
> the spec.
> ---
> virt/kvm/arm/vgic/vgic-its.c | 71 ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 69 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 27ebabd..24824be 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -1736,7 +1736,48 @@ static int lookup_table(struct vgic_its *its, gpa_t base, int size, int esz,
> */
> static int vgic_its_flush_pending_tables(struct vgic_its *its)
> {
> - return -ENXIO;
> + struct kvm *kvm = its->dev->kvm;
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + struct vgic_irq *irq;
> + int ret;
> +
> + /**
> + * we do not take the dist->lpi_list_lock since we have a garantee
> + * the LPI list is not touched while the its lock is held
Can you elaborate on what gives us this guarantee? I see that we have a
locking *order*, but that doesn't mean we can avoid taking the lock. So
to me it looks like we need to take the lpi_list_lock spinlock here,
which unfortunately breaks the kvm_read_guest() calls below.
If you agree on this, you can take a look at the INVALL implementation,
where I faced the same issue. The solution we came up with is
vgic_copy_lpi_list(), which you can call under the lock to create a
(private) copy of the LPI list, which you can later iterate without
holding the lock - and thus are free to call sleeping functions.
Cheers,
Andre.
> + */
> + list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> + struct kvm_vcpu *vcpu;
> + gpa_t pendbase, ptr;
> + bool stored;
> + u8 val;
> +
> + vcpu = irq->target_vcpu;
> + if (!vcpu)
> + return -EINVAL;
> +
> + pendbase = PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> +
> + ptr = pendbase + (irq->intid / BITS_PER_BYTE);
> +
> + ret = kvm_read_guest(kvm, (gpa_t)ptr, &val, 1);
> + if (ret)
> + return ret;
> +
> + stored = val & (irq->intid % BITS_PER_BYTE);
> + if (stored == irq->pending_latch)
> + continue;
> +
> + if (irq->pending_latch)
> + val |= 1 << (irq->intid % BITS_PER_BYTE);
> + else
> + val &= ~(1 << (irq->intid % BITS_PER_BYTE));
> +
> + ret = kvm_write_guest(kvm, (gpa_t)ptr, &val, 1);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> }
>
> /**
> @@ -1745,7 +1786,33 @@ static int vgic_its_flush_pending_tables(struct vgic_its *its)
> */
> static int vgic_its_restore_pending_tables(struct vgic_its *its)
> {
> - return -ENXIO;
> + struct vgic_irq *irq;
> + struct kvm *kvm = its->dev->kvm;
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + int ret;
> +
> + list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> + struct kvm_vcpu *vcpu;
> + gpa_t pendbase, ptr;
> + u8 val;
> +
> + vcpu = irq->target_vcpu;
> + if (!vcpu)
> + return -EINVAL;
> +
> + if (!(vcpu->arch.vgic_cpu.pendbaser & GICR_PENDBASER_PTZ))
> + return 0;
> +
> + pendbase = PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> +
> + ptr = pendbase + (irq->intid / BITS_PER_BYTE);
> +
> + ret = kvm_read_guest(kvm, (gpa_t)ptr, &val, 1);
> + if (ret)
> + return ret;
> + irq->pending_latch = val & (1 << (irq->intid % BITS_PER_BYTE));
> + }
> + return 0;
> }
>
> static int vgic_its_flush_ite(struct vgic_its *its, struct its_device *dev,
>
