Messages in this thread | | | Subject | Re: [PATCH 8/9] x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user() | From | Paolo Bonzini <> | Date | Sat, 30 May 2020 18:20:04 +0200 |
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> On Fri, May 29, 2020 at 04:52:59PM -0700, Linus Torvalds wrote: >> It looks like the argument for the address being validated is that it >> comes from "gfn_to_hva()", which should only return >> host-virtual-addresses. That may be true.
Yes, the access_ok is done in __kvm_set_memory_region and gfn_to_hva() returns a page-aligned address so it's obviously ok for a u32.
But I have no objections to removing the __ because if a read or write is in the hot path it will use kvm_write_guest_cached and similar.
Paolo
>> But "should" is not "does", and honestly, the cost of gfn_to_hva() is >> high enough that then using that as an argument for removing >> "access_ok()" smells.
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