From: Michal Wajdeczko <michal.wajdeczko@intel.com>
Date: Mon, 22 Jun 2026 13:23:39 +0000 (+0200)
Subject: drm/xe/mmio: Add check for minimal BAR size
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16bc4493bbf3be76b08e980b2f2380987c3ac9f4;p=linux

drm/xe/mmio: Add check for minimal BAR size

We initialized the root tile's xe_mmio structure with a new size
of 4MiB without sanity checks to see if mapped GTTMMADR_BAR was
actually at least that size. Check BAR size against first 16MiB,
which is expected minimum BAR size for the one-tile platforms.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20260622132342.19600-4-michal.wajdeczko@intel.com
---

diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
index fce890b6410c7..8dd818e1184c8 100644
--- a/drivers/gpu/drm/xe/xe_mmio.c
+++ b/drivers/gpu/drm/xe/xe_mmio.c
@@ -101,13 +101,18 @@ int xe_mmio_probe_early(struct xe_device *xe)
 	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
 	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
 
-	xe->mmio.size = pci_resource_len(pdev, GTTMMADR_BAR);
 	xe->mmio.regs = pcim_iomap(pdev, GTTMMADR_BAR, 0);
 	if (!xe->mmio.regs) {
 		xe_err(xe, "Failed to map GTTMMADR_BAR\n");
 		return -EIO;
 	}
 
+	xe->mmio.size = pci_resource_len(pdev, GTTMMADR_BAR);
+	if (xe->mmio.size < SZ_16M) {
+		xe_err(xe, "GTTMMADR_BAR is too small: %zu\n", xe->mmio.size);
+		return -EIO;
+	}
+
 	/* Setup first tile; other tiles (if present) will be setup later. */
 	xe_mmio_init(&root_tile->mmio, root_tile, xe->mmio.regs, SZ_4M);