[PATCH v5 3/6] drm/xe/vf: Add bounds checking for queried context and doorbell counts

Add explicit bounds checks for context and doorbells which can detect
and reject invalid configuration data from a misconfigured or
malfunctioning PF, preventing protocol violations and protecting VF
initialization.

Signed-off-by: Satyanarayana K V P <[email protected]>
Cc: Michal Wajdeczko <[email protected]>
---
V4 -> V5:
- Fixed review comments (Michal W).

V3 -> V4:
 - New commit
---
 drivers/gpu/drm/xe/xe_gt_sriov_vf.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
index 339ea0d3344c..81d68fe5ad7c 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
@@ -15,6 +15,7 @@
 #include "abi/guc_klvs_abi.h"
 #include "abi/guc_relay_actions_abi.h"
 #include "regs/xe_gt_regs.h"
+#include "regs/xe_guc_regs.h"
 
 #include "xe_assert.h"
 #include "xe_device.h"
@@ -581,6 +582,11 @@ static int vf_get_ctxs_cfg(struct xe_gt *gt)
 	if (unlikely(err))
 		return err;
 
+	if (num_ctxs > GUC_ID_MAX) {
+		xe_gt_sriov_err(gt, "Out of bound CTXs %u received\n", num_ctxs);
+		return -EPROTO;
+	}
+
 	if (config->num_ctxs && config->num_ctxs != num_ctxs) {
 		xe_gt_sriov_err(gt, "Unexpected CTXs reassignment: %u != %u\n",
 				num_ctxs, config->num_ctxs);
@@ -607,6 +613,11 @@ static int vf_get_dbs_cfg(struct xe_gt *gt)
 	if (unlikely(err))
 		return err;
 
+	if (num_dbs > GUC_NUM_DOORBELLS) {
+		xe_gt_sriov_err(gt, "Out of bound DBs %u received\n", num_dbs);
+		return -EPROTO;
+	}
+
 	if (config->num_dbs && config->num_dbs != num_dbs) {
 		xe_gt_sriov_err(gt, "Unexpected DBs reassignment: %u != %u\n",
 				num_dbs, config->num_dbs);
-- 
2.53.0