42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
From 14997d521d1cd0bb36c902ef1032f0d3f2a3c912 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
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Date: Tue, 10 Jun 2025 13:37:04 +0100
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Subject: [PATCH] hw/usb/hcd-ohci: skip automatic zero-init of large array
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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The 'ohci_service_iso_td' method has a 8k byte array used for copying
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data between guest and host. Skip the automatic zero-init of this
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array to eliminate the performance overhead in the I/O hot path.
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The 'buf' array will be fully initialized when reading data from guest
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memory.
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Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
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Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
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Message-id: 20250610123709.835102-27-berrange@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/usb/hcd-ohci.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
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index 71b54914d3..72a9f9f474 100644
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--- a/hw/usb/hcd-ohci.c
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+++ b/hw/usb/hcd-ohci.c
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@@ -577,7 +577,7 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed)
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USBDevice *dev;
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USBEndpoint *ep;
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USBPacket *pkt;
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- uint8_t buf[8192];
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+ QEMU_UNINITIALIZED uint8_t buf[8192];
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bool int_req;
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struct ohci_iso_td iso_td;
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uint32_t addr;
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--
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2.47.3
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