From 5fcf787582dd911df3a971718010bfca5a20e61d Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Tue, 1 Sep 2020 16:09:44 +0200 Subject: cirrus: handle wraparound in cirrus_invalidate_region Code simply asserts that there is no wraparound instead of handling it properly. The assert() can be triggered by the guest (must be privilidged inside the guest though). Fix it. Buglink: https://bugs.launchpad.net/qemu/+bug/1880189 Cc: Li Qiang Reported-by: Philippe Mathieu-Daudé Signed-off-by: Gerd Hoffmann Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Li Qiang Message-id: 20200901140944.24101-1-kraxel@redhat.com --- hw/display/cirrus_vga.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c index 02d9ed0bd4..41e71af08a 100644 --- a/hw/display/cirrus_vga.c +++ b/hw/display/cirrus_vga.c @@ -640,10 +640,16 @@ static void cirrus_invalidate_region(CirrusVGAState * s, int off_begin, } for (y = 0; y < lines; y++) { - off_cur = off_begin; + off_cur = off_begin & s->cirrus_addr_mask; off_cur_end = ((off_cur + bytesperline - 1) & s->cirrus_addr_mask) + 1; - assert(off_cur_end >= off_cur); - memory_region_set_dirty(&s->vga.vram, off_cur, off_cur_end - off_cur); + if (off_cur_end >= off_cur) { + memory_region_set_dirty(&s->vga.vram, off_cur, off_cur_end - off_cur); + } else { + /* wraparound */ + memory_region_set_dirty(&s->vga.vram, off_cur, + s->cirrus_addr_mask + 1 - off_cur); + memory_region_set_dirty(&s->vga.vram, 0, off_cur_end); + } off_begin += off_pitch; } } -- cgit v1.2.3-55-g7522