File 0160-cirrus-handle-negative-pitch-in-cir.patch of Package qemu.10254

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File 0160-cirrus-handle-negative-pitch-in-cir.patch of Package qemu.10254

From 491230390741644022e6405f821daffd1aba402a Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
Date: Wed, 25 Jan 2017 14:48:57 +0100
Subject: [PATCH] cirrus: handle negative pitch in cirrus_invalidate_region()

cirrus_invalidate_region() calls memory_region_set_dirty()
on a per-line basis, always ranging from off_begin to
off_begin+bytesperline. With a negative pitch off_begin
marks the top most used address and thus we need to do an
initial shift backwards by a line for negative pitches of
backward blits, otherwise the first iteration covers the
line going from the start offset forwards instead of
backwards.
Additionally since the start address is inclusive, if we
shift by a full `bytesperline` we move to the first address
*not* included in the blit, so we only shift by one less
than bytesperline.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Message-id: 1485352137-29367-1-git-send-email-w.bumiller@proxmox.com

[ kraxel: codestyle fixes ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit f153b563f8cf121aebf5a2fff5f0110faf58ccb3)
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/display/cirrus_vga.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index f20f46c600..106330f083 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -655,9 +655,14 @@ static void cirrus_invalidate_region(CirrusVGAState * s, int off_begin,
     int off_cur;
     int off_cur_end;
 
+    if (off_pitch < 0) {
+        off_begin -= bytesperline - 1;
+    }
+
     for (y = 0; y < lines; y++) {
 	off_cur = off_begin;
 	off_cur_end = (off_cur + bytesperline) & s->cirrus_addr_mask;
+        assert(off_cur_end >= off_cur);
         memory_region_set_dirty(&s->vga.vram, off_cur, off_cur_end - off_cur);
 	off_begin += off_pitch;
     }

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File 0160-cirrus-handle-negative-pitch-in-cir.patch of Package qemu.10254

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