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| author | Michael Brown | 2021-04-14 17:33:41 +0200 |
|---|---|---|
| committer | Michael Brown | 2021-04-14 17:33:41 +0200 |
| commit | 85d179f2c65d0a2afe9122b844a90c011d551ae1 (patch) | |
| tree | 4e28fe6260f2df4911089d7747408d9f0c359688 /src/interface/linux | |
| parent | [int13] Do not report INT 13 extension support for emulated floppies (diff) | |
| download | ipxe-85d179f2c65d0a2afe9122b844a90c011d551ae1.tar.gz ipxe-85d179f2c65d0a2afe9122b844a90c011d551ae1.tar.xz ipxe-85d179f2c65d0a2afe9122b844a90c011d551ae1.zip | |
[xen] Support scatter-gather to allow for jumbo frames
The use of jumbo frames for the Xen netfront virtual NIC requires the
use of scatter-gather ("feature-sg"), with the receive descriptor ring
becoming a list of page-sized buffers and the backend using as many
page buffers as required for each packet.
Since iPXE's abstraction of an I/O buffer does not include any sort of
scatter-gather list, this requires an extra allocation and copy on the
receive datapath for any packet that spans more than a single page.
This support is required in order to successfully boot an AWS EC2
virtual machine (with non-enhanced networking) via iSCSI if jumbo
frames are enabled, since the netback driver used in EC2 seems not to
allow "feature-sg" to be renegotiated once the Linux kernel driver
takes over.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/interface/linux')
0 files changed, 0 insertions, 0 deletions