[PATCH v4 4/5] KVM: arm64: vgic-its: Clear DTE when MAPD unmaps a device

[Jing Zhang]

From: Kunkun Jiang <jiangkunkun at huawei.com>

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.

Co-developed-by: Shusen Li <lishusen2 at huawei.com>
Signed-off-by: Shusen Li <lishusen2 at huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun at huawei.com>
[Jing: Update with entry write helper]
Signed-off-by: Jing Zhang <jingzhangos at google.com>
---
 arch/arm64/kvm/vgic/vgic-its.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 9ccf00731ad2..7f931e33a425 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -1139,9 +1139,11 @@ 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)
@@ -1162,7 +1164,7 @@ 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);
-- 
2.47.0.277.g8800431eea-goog