diff options
Diffstat (limited to 'drivers/xen/features.c')
| -rw-r--r-- | drivers/xen/features.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/xen/features.c b/drivers/xen/features.c new file mode 100644 index 0000000000..87f1828d40 --- /dev/null +++ b/drivers/xen/features.c @@ -0,0 +1,52 @@ +// 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); + } +} |