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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/include/ipxe | |
| 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/include/ipxe')
| -rw-r--r-- | src/include/ipxe/xengrant.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/include/ipxe/xengrant.h b/src/include/ipxe/xengrant.h index 451a3ceee..fcb7a7157 100644 --- a/src/include/ipxe/xengrant.h +++ b/src/include/ipxe/xengrant.h @@ -166,16 +166,17 @@ xengrant_invalidate ( struct xen_hypervisor *xen, grant_ref_t ref ) { * @v ref Grant reference * @v domid Domain ID * @v subflags Additional flags - * @v page Page start + * @v addr Physical address within page * @ret rc Return status code */ static inline __attribute__ (( always_inline )) int xengrant_permit_access ( struct xen_hypervisor *xen, grant_ref_t ref, - domid_t domid, unsigned int subflags, void *page ) { + domid_t domid, unsigned int subflags, + physaddr_t addr ) { struct grant_entry_header *hdr = xengrant_header ( xen, ref ); struct grant_entry_v1 *v1 = xengrant_v1 ( hdr ); union grant_entry_v2 *v2 = xengrant_v2 ( hdr ); - unsigned long frame = ( virt_to_phys ( page ) / PAGE_SIZE ); + unsigned long frame = ( addr / PAGE_SIZE ); /* Fail (for test purposes) if applicable */ if ( ( XENGRANT_FAIL_RATE > 0 ) && |