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Michal Orzel
81e823f1e9
Per the binding (docs/misc/arm/device-tree/guest.txt), region 0 for mapping grant table is large enough to map the whole grant table. Xen never checks that this holds: - enhanced dom0less domUs are given GUEST_GNTTAB_SIZE (4096 frames), while their limit comes from the max_grant_frames DT property or, if absent, from the gnttab_max_frames command line option or default, neither of which is bounded by the region size, - a dom0less hardware domain is given gnttab_dom0_frames() frames, while the max_grant_frames DT property can raise its limit above that. A guest growing its grant table past the end of the region ends up mapping grant frames over whatever follows it in its address space, e.g. the magic pages at GUEST_MAGIC_BASE for a domU. Validate that the configured max frames can actually fit in the region Xen exposes in make_hypervisor_node(). Fix find_gnttab_region() logic of setting the gnttab_size for hardware domain to allow the max frames up until the size of the text section. Otherwise, the DT setting would only allow to shrink it from the default. Fixes:79eb2871f2("xen/arm: configure dom0less domain for enabling xenstore after boot") Fixes:df68a4cb7e("xen/arm: Add capabilities to dom0less") Signed-off-by: Michal Orzel <michal.orzel@amd.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>