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/*
* Copyright (C) 2014 Citrix Systems R&D Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
#include "libxl_osdeps.h" /* must come before any other headers */
#include "libxl_internal.h"
#include <xenctrl.h>
#include <xen/hvm/params.h>
/*
* Generate a random VM generation ID.
*
* Returns ERROR_FAIL if a suitable source of random numbers is not
* available.
*
* See Microsoft's "Virtual Machine Generation ID" specification for
* further details, including when a new generation ID is required.
*
* http://www.microsoft.com/en-us/download/details.aspx?id=30707
*/
int libxl_ms_vm_genid_generate(libxl_ctx *ctx, libxl_ms_vm_genid *id)
{
GC_INIT(ctx);
int ret;
ret = libxl__random_bytes(gc, id->bytes, LIBXL_MS_VM_GENID_LEN);
GC_FREE;
return ret;
}
/*
* Is this VM generation ID all zeros?
*/
bool libxl_ms_vm_genid_is_zero(const libxl_ms_vm_genid *id)
{
static const libxl_ms_vm_genid zero;
return memcmp(id->bytes, zero.bytes, LIBXL_MS_VM_GENID_LEN) == 0;
}
void libxl_ms_vm_genid_copy(libxl_ctx *ctx, libxl_ms_vm_genid *dst,
const libxl_ms_vm_genid *src)
{
memcpy(dst, src, LIBXL_MS_VM_GENID_LEN);
}
int libxl__ms_vm_genid_set(libxl__gc *gc, uint32_t domid,
const libxl_ms_vm_genid *id)
{
libxl_ctx *ctx = libxl__gc_owner(gc);
const char *dom_path;
uint64_t genid[2];
uint64_t paddr = 0;
int rc;
memcpy(genid, id->bytes, LIBXL_MS_VM_GENID_LEN);
/*
* Set the "platform/generation-id" XenStore key to pass the ID to
* hvmloader.
*/
dom_path = libxl__xs_get_dompath(gc, domid);
if (!dom_path) {
rc = ERROR_FAIL;
goto out;
}
rc = libxl__xs_printf(gc, XBT_NULL,
GCSPRINTF("%s/platform/generation-id", dom_path),
"%"PRIu64 ":%" PRIu64, genid[0], genid[1]);
if (rc < 0)
goto out;
/*
* Update the ID in guest memory (if available).
*/
xc_hvm_param_get(ctx->xch, domid, HVM_PARAM_VM_GENERATION_ID_ADDR, &paddr);
if (paddr) {
void *vaddr;
vaddr = xc_map_foreign_range(ctx->xch, domid, XC_PAGE_SIZE,
PROT_READ | PROT_WRITE,
paddr >> XC_PAGE_SHIFT);
if (vaddr == NULL) {
rc = ERROR_FAIL;
goto out;
}
memcpy(vaddr + (paddr & ~XC_PAGE_MASK), genid, 2 * sizeof(*genid));
munmap(vaddr, XC_PAGE_SIZE);
/*
* The spec requires an ACPI Notify event is injected into the
* guest when the generation ID is changed.
*
* This is only called for domains that are suspended or newly
* created and they won't be in a state to receive such an
* event.
*/
}
rc = 0;
out:
return rc;
}
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