xen/arm: introduce XENFEAT_grant_map_identity (5ebc77de) · Commits · 戴 / test

The flag tells us that the hypervisor maps a grant page to guest physical address == machine address of the page in addition to the normal grant mapping address. It is needed to properly issue cache maintenance operation at the completion of a DMA operation involving a foreign grant. Signed-off-by:

Stefano Stabellini <stefano.stabellini@eu.citrix.com> Tested-by:

Denis Schneider <v1ne2go@gmail.com>

arch/arm/xen/enlighten.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -260,6 +260,12 @@ static int __init xen_guest_init(void)
		xen_domain_type = XEN_HVM_DOMAIN;

		xen_setup_features();

		if (!xen_feature(XENFEAT_grant_map_identity)) {
		pr_warn("Please upgrade your Xen.\n"
		"If your platform has any non-coherent DMA devices, they won't work properly.\n");
		}

		if (xen_feature(XENFEAT_dom0))
		xen_start_info->flags \|= SIF_INITDOMAIN\|SIF_PRIVILEGED;
		else

include/xen/interface/features.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,9 @@
		/* operation as Dom0 is supported */
		#define XENFEAT_dom0 11

		/* Xen also maps grant references at pfn = mfn */
		#define XENFEAT_grant_map_identity 12

		#define XENFEAT_NR_SUBMAPS 1

		#endif /* __XEN_PUBLIC_FEATURES_H__ */

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