File 0355-sm501-Log-unimplemented-raster-oper.patch of Package qemu.20756

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File 0355-sm501-Log-unimplemented-raster-oper.patch of Package qemu.20756

From: Sebastian Bauer <mail@sebastianbauer.info>
Date: Wed, 4 Jul 2018 11:40:58 +0200
Subject: sm501: Log unimplemented raster operation modes

Git-commit: 06cb926aaa51970fc009245bb5e15700c19a56f8
References: bsc#1172385, CVE-2020-12829

The sm501 currently implements only a very limited set of raster operation
modes. After this change, unknown raster operation modes are logged so
these can be easily spotted.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/display/sm501.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index aaeb4f30322acf4681bb3ab255f0..25246a3e903377b2b723c1774987 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -672,6 +672,8 @@ static void sm501_2d_operation(SM501State * s)
     int format_flags = (s->twoD_stretch >> 20) & 0x3;
     int addressing = (s->twoD_stretch >> 16) & 0xF;
     int rop_mode = (s->twoD_control >> 15) & 0x1; /* 1 for rop2, else rop3 */
+    /* 1 if rop2 source is the pattern, otherwise the source is the bitmap */
+    int rop2_source_is_pattern = (s->twoD_control >> 14) & 0x1;
     int rop = s->twoD_control & 0xFF;
 
     /* get frame buffer info */
@@ -685,6 +687,27 @@ static void sm501_2d_operation(SM501State * s)
         abort();
     }
 
+    if (rop_mode == 0) {
+        if (rop != 0xcc) {
+            /* Anything other than plain copies are not supported */
+            qemu_log_mask(LOG_UNIMP, "sm501: rop3 mode with rop %x is not "
+                          "supported.\n", rop);
+        }
+    } else {
+        if (rop2_source_is_pattern && rop != 0x5) {
+            /* For pattern source, we support only inverse dest */
+            qemu_log_mask(LOG_UNIMP, "sm501: rop2 source being the pattern and "
+                          "rop %x is not supported.\n", rop);
+        } else {
+            if (rop != 0x5 && rop != 0xc) {
+                /* Anything other than plain copies or inverse dest is not
+                 * supported */
+                qemu_log_mask(LOG_UNIMP, "sm501: rop mode %x is not "
+                              "supported.\n", rop);
+            }
+        }
+    }
+
     if ((s->twoD_source_base & 0x08000000) ||
         (s->twoD_destination_base & 0x08000000)) {
         printf("%s: only local memory is supported.\n", __func__);

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File 0355-sm501-Log-unimplemented-raster-oper.patch of Package qemu.20756

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