Michael Brown
036af27a45
Add basic support for Xen PV-HVM domains (detected via the Xen platform PCI device with IDs 5853:0001), including support for accessing configuration via XenStore and enumerating devices via XenBus. Signed-off-by: Michael Brown <mcb30@ipxe.org>
126 lines
3.3 KiB
C
126 lines
3.3 KiB
C
/*
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* Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <stdint.h>
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#include <errno.h>
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#include <assert.h>
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#include <ipxe/io.h>
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#include <ipxe/xen.h>
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#include <ipxe/xengrant.h>
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/** @file
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*
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* Xen grant tables
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*
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*/
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/**
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* Allocate grant references
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*
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* @v xen Xen hypervisor
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* @v refs Grant references to fill in
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* @v count Number of references
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* @ret rc Return status code
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*/
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int xengrant_alloc ( struct xen_hypervisor *xen, grant_ref_t *refs,
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unsigned int count ) {
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union grant_entry_v2 *entry;
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unsigned int mask = ( xen->grant.count - 1 );
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unsigned int check = 0;
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unsigned int avail;
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unsigned int ref;
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/* Fail unless we have enough references available */
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avail = ( xen->grant.count - xen->grant.used -
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GNTTAB_NR_RESERVED_ENTRIES );
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if ( avail < count ) {
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DBGC ( xen, "XENGRANT cannot allocate %d references (only %d "
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"of %d available)\n", count, avail, xen->grant.count );
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return -ENOBUFS;
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}
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DBGC ( xen, "XENGRANT allocating %d references (from %d of %d "
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"available)\n", count, avail, xen->grant.count );
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/* Update number of references used */
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xen->grant.used += count;
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/* Find unused references */
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for ( ref = xen->grant.ref ; count ; ref = ( ( ref + 1 ) & mask ) ) {
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/* Sanity check */
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assert ( check++ < xen->grant.count );
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/* Skip reserved references */
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if ( ref < GNTTAB_NR_RESERVED_ENTRIES )
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continue;
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/* Skip in-use references */
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entry = &xen->grant.table[ref];
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if ( readw ( &entry->hdr.flags ) & GTF_type_mask )
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continue;
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if ( readw ( &entry->hdr.domid ) == DOMID_SELF )
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continue;
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/* Mark reference as in-use. We leave the flags as
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* empty (to avoid creating a valid grant table entry)
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* and set the domid to DOMID_SELF.
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*/
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writew ( DOMID_SELF, &entry->hdr.domid );
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DBGC2 ( xen, "XENGRANT allocated ref %d\n", ref );
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/* Record reference */
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refs[--count] = ref;
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}
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/* Update cursor */
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xen->grant.ref = ref;
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return 0;
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}
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/**
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* Free grant references
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*
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* @v xen Xen hypervisor
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* @v refs Grant references
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* @v count Number of references
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*/
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void xengrant_free ( struct xen_hypervisor *xen, grant_ref_t *refs,
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unsigned int count ) {
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union grant_entry_v2 *entry;
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unsigned int ref;
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unsigned int i;
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/* Free references */
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for ( i = 0 ; i < count ; i++ ) {
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/* Sanity check */
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ref = refs[i];
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assert ( ref < xen->grant.count );
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/* Mark reference as unused */
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entry = &xen->grant.table[ref];
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writew ( 0, &entry->hdr.flags );
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writew ( 0, &entry->hdr.domid );
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DBGC2 ( xen, "XENGRANT freed ref %d\n", ref );
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}
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}
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