Re: [PATCH v7 22/24] KVM: arm64: vgic-its: ITT save and restore

Marc Zyngier
2017-05-07T13:36:34Z

On Sat, May 06 2017 at 4:24:41 pm BST, Eric Auger <eric.auger@redhat.com> wrote:
> Implement routines to save and restore device ITT and their
> interrupt table entries (ITE).
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Christoffer Dall <cdall@linaro.org>
>
> ---
> v6 -> v7:
> - added Christoffer's R-b
>
> v5 -> v6:
> - accomodate vgic_its_alloc_ite change of proto
> - check LPI ID on restore, check eventid offset
> - initializations on separate line
> - coming after device save/restore
> - add_lpi does config and pending bit sync
>
> v4 -> v5:
> - ITE are now sorted by eventid on the flush
> - rename *flush* into *save*
> - use macros for shits and masks
> - pass ite_esz to vgic_its_save_ite
>
> v3 -> v4:
> - lookup_table and compute_next_eventid_offset become static in this
> patch
> - remove static along with vgic_its_flush/restore_itt to avoid
> compilation warnings
> - next field only computed with a shift (mask removed)
> - handle the case where the last element has not been found
>
> v2 -> v3:
> - add return 0 in vgic_its_restore_ite (was in subsequent patch)
>
> v2: creation
> ---
> virt/kvm/arm/vgic/vgic-its.c | 116 +++++++++++++++++++++++++++++++++++++++++--
> virt/kvm/arm/vgic/vgic.h | 4 ++
> 2 files changed, 117 insertions(+), 3 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 3dea626..adb3d9e 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -1750,7 +1750,7 @@ static u32 compute_next_devid_offset(struct list_head *h,
> return min_t(u32, next_offset, VITS_DTE_MAX_DEVID_OFFSET);
> }
>
> -u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite)
> +static u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite)
> {
> struct its_ite *next;
> u32 next_offset;
> @@ -1827,14 +1827,124 @@ static int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,
> return ret;
> }
>
> +/**
> + * vgic_its_save_ite - Save an interrupt translation entry at @gpa
> + */
> +static int vgic_its_save_ite(struct vgic_its *its, struct its_device *dev,
> + struct its_ite *ite, gpa_t gpa, int ite_esz)
> +{
> + struct kvm *kvm = its->dev->kvm;
> + u32 next_offset;
> + u64 val;
> +
> + next_offset = compute_next_eventid_offset(&dev->itt_head, ite);
> + val = ((u64)next_offset << KVM_ITS_ITE_NEXT_SHIFT) |
> + ((u64)ite->lpi << KVM_ITS_ITE_PINTID_SHIFT) |
> + ite->collection->collection_id;
> + val = cpu_to_le64(val);
> + return kvm_write_guest(kvm, gpa, &val, ite_esz);
> +}
> +
> +/**
> + * vgic_its_restore_ite - restore an interrupt translation entry
> + * @event_id: id used for indexing
> + * @ptr: pointer to the ITE entry
> + * @opaque: pointer to the its_device
> + */
> +static int vgic_its_restore_ite(struct vgic_its *its, u32 event_id,
> + void *ptr, void *opaque)
> +{
> + struct its_device *dev = (struct its_device *)opaque;
> + struct its_collection *collection;
> + struct kvm *kvm = its->dev->kvm;
> + struct kvm_vcpu *vcpu = NULL;
> + u64 val;
> + u64 *p = (u64 *)ptr;
> + struct vgic_irq *irq;
> + u32 coll_id, lpi_id;
> + struct its_ite *ite;
> + u32 offset;
> +
> + val = *p;
> +
> + val = le64_to_cpu(val);
> +
> + coll_id = val & KVM_ITS_ITE_ICID_MASK;
> + lpi_id = (val & KVM_ITS_ITE_PINTID_MASK) >> KVM_ITS_ITE_PINTID_SHIFT;
> +
> + if (!lpi_id)
> + return 1; /* invalid entry, no choice but to scan next entry */
> +
> + if (lpi_id < VGIC_MIN_LPI)
> + return -EINVAL;
> +
> + offset = val >> KVM_ITS_ITE_NEXT_SHIFT;
> + if (event_id + offset >= BIT_ULL(dev->num_eventid_bits))
> + return -EINVAL;
> +
> + collection = find_collection(its, coll_id);
> + if (!collection)
> + return -EINVAL;
> +
> + ite = vgic_its_alloc_ite(dev, collection, lpi_id, event_id);
> + if (IS_ERR(ite))
> + return PTR_ERR(ite);
> +
> + if (its_is_collection_mapped(collection))
> + vcpu = kvm_get_vcpu(kvm, collection->target_addr);
> +
> + irq = vgic_add_lpi(kvm, lpi_id, vcpu);
> + if (IS_ERR(irq))
> + return PTR_ERR(irq);

Same remark as the previous patch: the its_ite structure should be freed
on failure. Otherwise, I suspect we end0up leaking memory.

Thanks,

M.
--
Jazz is not dead, it just smell funny.