linux-stable/drivers/xen/features.c
Juergen Gross ac4c403c90 xen: check required Xen features
Linux kernel is not supported to run on Xen versions older than 4.0.

Add tests for required Xen features always being present in Xen 4.0
and newer.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210730071804.4302-2-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
2021-08-30 11:57:45 +02:00

52 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
* features.c
*
* Xen feature flags.
*
* Copyright (c) 2006, Ian Campbell, XenSource Inc.
*/
#include <linux/types.h>
#include <linux/cache.h>
#include <linux/export.h>
#include <linux/printk.h>
#include <asm/xen/hypercall.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/interface/version.h>
#include <xen/features.h>
/*
* Linux kernel expects at least Xen 4.0.
*
* Assume some features to be available for that reason (depending on guest
* mode, of course).
*/
#define chk_required_feature(f) { \
if (!xen_feature(f)) \
panic("Xen: feature %s not available!\n", #f); \
}
u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
EXPORT_SYMBOL_GPL(xen_features);
void xen_setup_features(void)
{
struct xen_feature_info fi;
int i, j;
for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {
fi.submap_idx = i;
if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
break;
for (j = 0; j < 32; j++)
xen_features[i * 32 + j] = !!(fi.submap & 1<<j);
}
if (xen_pv_domain()) {
chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad);
chk_required_feature(XENFEAT_gnttab_map_avail_bits);
}
}