KVM: arm64: vgic-its: Clear DTE when MAPD unmaps a device

commit e9649129d33dca561305fc590a7c4ba8c3e5675a upstream.

vgic_its_save_device_tables will traverse its->device_list to
save DTE for each device. vgic_its_restore_device_tables will
traverse each entry of device table and check if it is valid.
Restore if valid.

But when MAPD unmaps a device, it does not invalidate the
corresponding DTE. In the scenario of continuous saves
and restores, there may be a situation where a device's DTE
is not saved but is restored. This is unreasonable and may
cause restore to fail. This patch clears the corresponding
DTE when MAPD unmaps a device.

Cc: stable@vger.kernel.org
Fixes: 57a9a117154c ("KVM: arm64: vgic-its: Device table save/restore")
Co-developed-by: Shusen Li <lishusen2@huawei.com>
Signed-off-by: Shusen Li <lishusen2@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
[Jing: Update with entry write helper]
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20241107214137.428439-5-jingzhangos@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 9769911663a4b7a4d0f75a565e4d73b0724ac969..198296933e7ebf4a1308cf1e3372a89094198357 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -1143,9 +1143,11 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
        bool valid = its_cmd_get_validbit(its_cmd);
        u8 num_eventid_bits = its_cmd_get_size(its_cmd);
        gpa_t itt_addr = its_cmd_get_ittaddr(its_cmd);
+       int dte_esz = vgic_its_get_abi(its)->dte_esz;
        struct its_device *device;
+       gpa_t gpa;
 
-       if (!vgic_its_check_id(its, its->baser_device_table, device_id, NULL))
+       if (!vgic_its_check_id(its, its->baser_device_table, device_id, &gpa))
                return E_ITS_MAPD_DEVICE_OOR;
 
        if (valid && num_eventid_bits > VITS_TYPER_IDBITS)
@@ -1166,7 +1168,7 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
         * is an error, so we are done in any case.
         */
        if (!valid)
-               return 0;
+               return vgic_its_write_entry_lock(its, gpa, 0, dte_esz);
 
        device = vgic_its_alloc_device(its, device_id, itt_addr,
                                       num_eventid_bits);