diff mbox series

[PULL,8/8] vfio/igd: correctly calculate stolen memory size for gen 9 and later

Message ID 20240917103229.876515-9-clg@redhat.com (mailing list archive)
State New
Headers show
Series [PULL,1/8] hw/vfio/pci.c: Use correct type in trace_vfio_msix_early_setup() | expand

Commit Message

Cédric Le Goater Sept. 17, 2024, 10:32 a.m. UTC 
From: Corvin Köhne <corvin.koehne@gmail.com>

We have to update the calculation of the stolen memory size because
we've seen devices using values of 0xf0 and above for the graphics mode
select field. The new calculation was taken from the linux kernel [1].

[1] https://github.com/torvalds/linux/blob/7c626ce4bae1ac14f60076d00eafe71af30450ba/arch/x86/kernel/early-quirks.c#L455-L460

Signed-off-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/igd.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index 0751c43eae04aac5152c627af648319151ee1e39..a95d441f68661c23eee976be5d74b2da354f9498 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -488,11 +488,18 @@  static int igd_get_stolen_mb(int gen, uint32_t gmch)
         gms = (gmch >> 8) & 0xff;
     }
 
-    if (gms > 0x10) {
-        error_report("Unsupported IGD GMS value 0x%x", gms);
-        return 0;
+    if (gen < 9) {
+        if (gms > 0x10) {
+            error_report("Unsupported IGD GMS value 0x%x", gms);
+            return 0;
+        }
+        return gms * 32;
+    } else {
+        if (gms < 0xf0)
+            return gms * 32;
+        else
+            return gms * 4 + 4;
     }
-    return gms * 32;
 }
 
 void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)