linux/drivers/xen/features.c
Julien Grall ecb6237fa3 x86/xen: Remove undefined behavior in setup_features()
1 << 31 is undefined. So switch to 1U << 31.

Fixes: 5ead97c84f ("xen: Core Xen implementation")
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220617103037.57828-1-julien@xen.org
Signed-off-by: Juergen Gross <jgross@suse.com>
2022-06-21 16:36:11 +02:00

53 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 & 1U << j);
}
if (xen_pv_domain()) {
chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad);
chk_required_feature(XENFEAT_gnttab_map_avail_bits);
}
}