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