[{"id":3677291,"web_url":"http://patchwork.ozlabs.org/comment/3677291/","msgid":"","list_archive_url":null,"date":"2026-04-14T15:51:12","subject":"Re: [PATCH v2 2/2] ati-vga: mask out lock bit from CUR_OFFSET in\n cursor offset calculation","submitter":{"id":16148,"url":"http://patchwork.ozlabs.org/api/people/16148/","name":"BALATON Zoltan","email":"balaton@eik.bme.hu"},"content":"On Wed, 15 Apr 2026, Junjie Cao wrote:\n> Bit 31 of CUR_OFFSET is the cursor lock bit, not part of the actual\n> cursor address (bits 26:4). Although the callers already check for the\n> lock bit and return early, mask it out with 0x07fffff0 when computing\n> the cursor source offset so the calculation only uses the address bits.\n>\n> Suggested-by: BALATON Zoltan \n> Signed-off-by: Junjie Cao \n\nReviewed-by: BALATON Zoltan \n\n> ---\n> hw/display/ati.c | 8 +++++---\n> 1 file changed, 5 insertions(+), 3 deletions(-)\n>\n> diff --git a/hw/display/ati.c b/hw/display/ati.c\n> index 0489995d00..3a7d45a882 100644\n> --- a/hw/display/ati.c\n> +++ b/hw/display/ati.c\n> @@ -147,7 +147,7 @@ static void ati_cursor_define(ATIVGAState *s)\n> return; /* Do not update cursor if locked or rendered by guest */\n> }\n> /* FIXME handle cur_hv_offs correctly */\n> - srcoff = s->regs.cur_offset - (s->regs.cur_hv_offs >> 16) -\n> + srcoff = (s->regs.cur_offset & 0x07fffff0) - (s->regs.cur_hv_offs >> 16) -\n> (s->regs.cur_hv_offs & 0xffff) * 16;\n> if (srcoff > s->vga.vram_size - 64 * 16) {\n> return;\n> @@ -176,13 +176,15 @@ static void ati_cursor_invalidate(VGACommonState *vga)\n> if (s->cursor_size != size ||\n> vga->hw_cursor_x != s->regs.cur_hv_pos >> 16 ||\n> vga->hw_cursor_y != (s->regs.cur_hv_pos & 0xffff) ||\n> - s->cursor_offset != s->regs.cur_offset - (s->regs.cur_hv_offs >> 16) -\n> + s->cursor_offset != (s->regs.cur_offset & 0x07fffff0) -\n> + (s->regs.cur_hv_offs >> 16) -\n> (s->regs.cur_hv_offs & 0xffff) * 16) {\n> /* Remove old cursor then update and show new one if needed */\n> vga_invalidate_scanlines(vga, vga->hw_cursor_y, vga->hw_cursor_y + 63);\n> vga->hw_cursor_x = s->regs.cur_hv_pos >> 16;\n> vga->hw_cursor_y = s->regs.cur_hv_pos & 0xffff;\n> - s->cursor_offset = s->regs.cur_offset - (s->regs.cur_hv_offs >> 16) -\n> + s->cursor_offset = (s->regs.cur_offset & 0x07fffff0) -\n> + (s->regs.cur_hv_offs >> 16) -\n> (s->regs.cur_hv_offs & 0xffff) * 16;\n> s->cursor_size = size;\n> if (size) {\n>","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":"legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Tue, 14 Apr 2026 17:51:12 +0200 (CEST)","by zero.eik.bme.hu (Postfix, from userid 432)\n id CAFF4596A23; Tue, 14 Apr 2026 17:51:12 +0200 (CEST)","from localhost (localhost [127.0.0.1])\n by zero.eik.bme.hu (Postfix) with ESMTP id C8E8D5969EC;\n Tue, 14 Apr 2026 17:51:12 +0200 (CEST)"],"X-Virus-Scanned":"amavis at eik.bme.hu","Date":"Tue, 14 Apr 2026 17:51:12 +0200 (CEST)","From":"BALATON Zoltan ","To":"Junjie Cao ","cc":"qemu-devel@nongnu.org,\n =?iso-8859-15?q?Philippe_Mathieu-Daud=E9?= ,\n Chad Jablonski , qemu-stable@nongnu.org","Subject":"Re: [PATCH v2 2/2] ati-vga: mask out lock bit from CUR_OFFSET in\n cursor offset calculation","In-Reply-To":"<20260414213523.1125859-2-junjie.cao@intel.com>","Message-ID":"","References":"<20260414213523.1125859-1-junjie.cao@intel.com>\n <20260414213523.1125859-2-junjie.cao@intel.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=US-ASCII; format=flowed","Received-SPF":"pass client-ip=2001:738:2001:2001::2001;\n envelope-from=balaton@eik.bme.hu; 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