From: Eric Auger <eric.au...@redhat.com>

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.

Reviewed-by: Marc Zyngier <marc.zyng...@arm.com>
Reviewed-by: Christoffer Dall <christoffer.d...@linaro.org>
Signed-off-by: Eric Auger <eric.au...@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.d...@linaro.org>
---
 virt/kvm/arm/vgic/vgic-its.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index d46256c07ba5..1732e08a4375 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1431,7 +1431,7 @@ 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, table_type;
        u64 reg, *regptr, clearbits = 0;
 
        /* When GITS_CTLR.Enable is 1, we ignore write accesses. */
@@ -1442,12 +1442,12 @@ 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;
+               table_type = GITS_BASER_TYPE_DEVICE;
                break;
        case 1:
                regptr = &its->baser_coll_table;
                entry_size = abi->cte_esz;
-               device_type = GITS_BASER_TYPE_COLLECTION;
+               table_type = GITS_BASER_TYPE_COLLECTION;
                clearbits = GITS_BASER_INDIRECT;
                break;
        default:
@@ -1459,10 +1459,24 @@ 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 |= table_type << GITS_BASER_TYPE_SHIFT;
        reg = vgic_sanitise_its_baser(reg);
 
        *regptr = reg;
+
+       if (!(reg & GITS_BASER_VALID)) {
+               /* Take the its_lock to prevent a race with a save/restore */
+               mutex_lock(&its->its_lock);
+               switch (table_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;
+               }
+               mutex_unlock(&its->its_lock);
+       }
 }
 
 static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
-- 
2.14.2

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