From 886a2ce3ff5c05087dc667578d59a37bfedaee19 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 10 Jun 2025 13:36:54 +0100 Subject: [PATCH 24/43] hw/display/vmware_vga: skip automatic zero-init of large struct MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Stefan Hajnoczi RH-MergeRequest: 381: Solve -ftrivial-auto-var-init performance regression with QEMU_UNINITIALIZED RH-Jira: RHEL-95479 RH-Acked-by: Miroslav Rezanina RH-Commit: [16/31] 201c9ceb2782d17dc9ca800b2d924a8ee3a8eb98 (stefanha/centos-stream-qemu-kvm) The 'vmsvga_fifo_run' method has a struct which is a little over 20k in size, used for holding image data for cursor changes. Skip the automatic zero-init of this struct to eliminate the performance overhead in the I/O hot path. The cursor variable will be fully initialized only when processing a cursor definition message from the guest. Signed-off-by: Daniel P. Berrangé Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-17-berrange@redhat.com Signed-off-by: Stefan Hajnoczi (cherry picked from commit 7048e70f391df76d009eecca25f8027858f9f304) Signed-off-by: Stefan Hajnoczi --- hw/display/vmware_vga.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/display/vmware_vga.c b/hw/display/vmware_vga.c index 2dd661e3c1..fae10068cb 100644 --- a/hw/display/vmware_vga.c +++ b/hw/display/vmware_vga.c @@ -618,7 +618,7 @@ static void vmsvga_fifo_run(struct vmsvga_state_s *s) uint32_t cmd, colour; int args, len, maxloop = 1024; int x, y, dx, dy, width, height; - struct vmsvga_cursor_definition_s cursor; + QEMU_UNINITIALIZED struct vmsvga_cursor_definition_s cursor; uint32_t cmd_start; len = vmsvga_fifo_length(s); -- 2.39.3