[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v3 5/7] xen/memory: Improve compat XENMEM_acquire_resource handling
On 12.01.2021 20:48, Andrew Cooper wrote: > @@ -446,6 +430,31 @@ int compat_memory_op(unsigned int cmd, > XEN_GUEST_HANDLE_PARAM(void) compat) > > #undef XLAT_mem_acquire_resource_HNDL_frame_list > > + if ( xen_frame_list && cmp.mar.nr_frames ) > + { > + /* > + * frame_list is an input for translated guests, and an > output > + * for untranslated guests. Only copy in for translated > guests. > + */ > + if ( paging_mode_translate(currd) ) > + { > + compat_pfn_t *compat_frame_list = (void *)xen_frame_list; > + > + if ( !compat_handle_okay(cmp.mar.frame_list, > + cmp.mar.nr_frames) || > + __copy_from_compat_offset( > + compat_frame_list, cmp.mar.frame_list, > + 0, cmp.mar.nr_frames) ) > + return -EFAULT; > + > + /* > + * Iterate backwards over compat_frame_list[] expanding > + * compat_pfn_t to xen_pfn_t in place. > + */ > + for ( int x = cmp.mar.nr_frames - 1; x >= 0; --x ) > + xen_frame_list[x] = compat_frame_list[x]; Just as a nit, without requiring you to adjust (but with the request to consider adjusting) - x getting used as array index would generally suggest it wants to be an unsigned type (despite me guessing the compiler ought to be able to avoid an explicit sign-extension for the actual memory accesses): for ( unsigned int x = cmp.mar.nr_frames; x--; ) xen_frame_list[x] = compat_frame_list[x]; Jan
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