Re: [PATCH] qxl: don't assert() if device isn't yet initialized

[Thomas Huth]

On 14/08/2023 21.33, marcandre.lur...@redhat.com wrote:

From: Marc-André Lureau <marcandre.lur...@redhat.com>

If the PCI BAR isn't yet mapped or was unmapped, QXL_IO_SET_MODE will
assert(). Instead, report a guest bug and keep going.

This can be reproduced with:

cat << EOF | ./qemu-system-x86_64 -vga qxl -m 2048 -nodefaults -qtest stdio
outl 0xcf8 0x8000101c
outl 0xcfc 0xc000
outl 0xcf8 0x80001001
outl 0xcfc 0x01000000
outl 0xc006 0x00
EOF

Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1829

Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
  hw/display/qxl.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index f1c0eb7dfc..70b73820b2 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -1591,7 +1591,10 @@ static void qxl_set_mode(PCIQXLDevice *d, unsigned int 
modenr, int loadvm)
      }

d->guest_slots[0].slot = slot;

-    assert(qxl_add_memslot(d, 0, devmem, QXL_SYNC) == 0);
+    if (qxl_add_memslot(d, 0, devmem, QXL_SYNC) != 0) {
+        qxl_set_guest_bug(d, "device isn't initialized yet");
+        return;
+    }

d->guest_primary.surface = surface;

      qxl_create_guest_primary(d, 0, QXL_SYNC);

Reviewed-by: Thomas Huth <th...@redhat.com>