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    Subject[PATCH v4 09/11] KVM: arm/arm64: vgic-its: free caches when GITS_BASER Valid bit is cleared
    Date
    When the GITS_BASER<n>.Valid gets cleared, the data structures in
    guest RAM are not valid anymore. The device, collection
    and LPI lists stored in the in-kernel ITS represent the same
    information in some form of cache. So let's void the cache.

    Signed-off-by: Eric Auger <eric.auger@redhat.com>

    ---

    v2 -> v3:
    - add a comment and clear cache in if block
    ---
    virt/kvm/arm/vgic/vgic-its.c | 23 +++++++++++++++++++----
    1 file changed, 19 insertions(+), 4 deletions(-)

    diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
    index f3f0026f..084239c 100644
    --- a/virt/kvm/arm/vgic/vgic-its.c
    +++ b/virt/kvm/arm/vgic/vgic-its.c
    @@ -1471,8 +1471,9 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm,
    unsigned long val)
    {
    const struct vgic_its_abi *abi = vgic_its_get_abi(its);
    - u64 entry_size, device_type;
    + u64 entry_size;
    u64 reg, *regptr, clearbits = 0;
    + int type;

    /* When GITS_CTLR.Enable is 1, we ignore write accesses. */
    if (its->enabled)
    @@ -1482,12 +1483,12 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm,
    case 0:
    regptr = &its->baser_device_table;
    entry_size = abi->dte_esz;
    - device_type = GITS_BASER_TYPE_DEVICE;
    + type = GITS_BASER_TYPE_DEVICE;
    break;
    case 1:
    regptr = &its->baser_coll_table;
    entry_size = abi->cte_esz;
    - device_type = GITS_BASER_TYPE_COLLECTION;
    + type = GITS_BASER_TYPE_COLLECTION;
    clearbits = GITS_BASER_INDIRECT;
    break;
    default:
    @@ -1499,10 +1500,24 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm,
    reg &= ~clearbits;

    reg |= (entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT;
    - reg |= device_type << GITS_BASER_TYPE_SHIFT;
    + reg |= (u64)type << GITS_BASER_TYPE_SHIFT;
    reg = vgic_sanitise_its_baser(reg);

    *regptr = reg;
    +
    + /* Table no longer valid: clear cached data */
    + if (!(reg & GITS_BASER_VALID)) {
    + switch (type) {
    + case GITS_BASER_TYPE_DEVICE:
    + vgic_its_free_device_list(kvm, its);
    + break;
    + case GITS_BASER_TYPE_COLLECTION:
    + vgic_its_free_collection_list(kvm, its);
    + break;
    + default:
    + break;
    + }
    + }
    }

    static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
    --
    2.5.5
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