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hw/usb/hcd-ohci: skip automatic zero-init of large array

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The 'ohci_service_iso_td' method has a 8k byte array used for copying
data between guest and host. Skip the automatic zero-init of this
array to eliminate the performance overhead in the I/O hot path.

The 'buf' array will be fully initialized when reading data from guest
memory.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20250610123709.835102-27-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2025-06-10 13:37:04 +01:00 • committed by Stefan Hajnoczi
parent 5dd9087fff
commit 14997d521d
1 changed files with 1 additions and 1 deletions
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2
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)
USBDevice *dev;
USBEndpoint *ep;
USBPacket *pkt;
uint8_t buf[8192];
QEMU_UNINITIALIZED uint8_t buf[8192];
bool int_req;
struct ohci_iso_td iso_td;
uint32_t addr;