1 | // SPDX-License-Identifier: GPL-2.0-only |
---|---|
2 | /****************************************************************************** |
3 | * features.c |
4 | * |
5 | * Xen feature flags. |
6 | * |
7 | * Copyright (c) 2006, Ian Campbell, XenSource Inc. |
8 | */ |
9 | #include <linux/types.h> |
10 | #include <linux/cache.h> |
11 | #include <linux/export.h> |
12 | #include <linux/printk.h> |
13 | |
14 | #include <asm/xen/hypercall.h> |
15 | |
16 | #include <xen/xen.h> |
17 | #include <xen/interface/xen.h> |
18 | #include <xen/interface/version.h> |
19 | #include <xen/features.h> |
20 | |
21 | /* |
22 | * Linux kernel expects at least Xen 4.0. |
23 | * |
24 | * Assume some features to be available for that reason (depending on guest |
25 | * mode, of course). |
26 | */ |
27 | #define chk_required_feature(f) { \ |
28 | if (!xen_feature(f)) \ |
29 | panic("Xen: feature %s not available!\n", #f); \ |
30 | } |
31 | |
32 | u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly; |
33 | EXPORT_SYMBOL_GPL(xen_features); |
34 | |
35 | void xen_setup_features(void) |
36 | { |
37 | struct xen_feature_info fi; |
38 | int i, j; |
39 | |
40 | for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) { |
41 | fi.submap_idx = i; |
42 | if (HYPERVISOR_xen_version(XENVER_get_features, arg: &fi) < 0) |
43 | break; |
44 | for (j = 0; j < 32; j++) |
45 | xen_features[i * 32 + j] = !!(fi.submap & 1U << j); |
46 | } |
47 | |
48 | if (xen_pv_domain()) { |
49 | chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad); |
50 | chk_required_feature(XENFEAT_gnttab_map_avail_bits); |
51 | } |
52 | } |
53 |