linux-kernel - Re: [PATCH] powerpc/svm: Don't issue ultracalls if !mem_encrypt

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <871r7cks8x.fsf@mpe.ellerman.id.au>
Date:   Mon, 02 Aug 2021 21:20:30 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Will Deacon <will@...nel.org>, linux-kernel@...r.kernel.org,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     Sachin Sant <sachinp@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org, Robin Murphy <robin.murphy@....com>,
        Nicholas Piggin <npiggin@...il.com>,
        Nathan Chancellor <nathan@...nel.org>,
        iommu@...ts.linux-foundation.org,
        Claire Chang <tientzu@...omium.org>,
        Will Deacon <will@...nel.org>, Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] powerpc/svm: Don't issue ultracalls if
 !mem_encrypt_active()

Will Deacon <will@...nel.org> writes:
> Commit ad6c00283163 ("swiotlb: Free tbl memory in swiotlb_exit()")
> introduced a set_memory_encrypted() call to swiotlb_exit() so that the
> buffer pages are returned to an encrypted state prior to being freed.
>
> Sachin reports that this leads to the following crash on a Power server:
>
> [    0.010799] software IO TLB: tearing down default memory pool
> [    0.010805] ------------[ cut here ]------------
> [    0.010808] kernel BUG at arch/powerpc/kernel/interrupt.c:98!
>
> Nick spotted that this is because set_memory_encrypted() is issuing an
> ultracall which doesn't exist for the processor, and should therefore
> be gated by mem_encrypt_active() to mirror the x86 implementation.
>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Cc: Claire Chang <tientzu@...omium.org>
> Cc: Christoph Hellwig <hch@....de>
> Cc: Robin Murphy <robin.murphy@....com>
> Fixes: ad6c00283163 ("swiotlb: Free tbl memory in swiotlb_exit()")
> Suggested-by: Nicholas Piggin <npiggin@...il.com>
> Reported-by: Sachin Sant <sachinp@...ux.vnet.ibm.com>
> Tested-by: Sachin Sant <sachinp@...ux.vnet.ibm.com>
> Tested-by: Nathan Chancellor <nathan@...nel.org>
> Link: https://lore.kernel.org/r/1905CD70-7656-42AE-99E2-A31FC3812EAC@linux.vnet.ibm.com/
> Signed-off-by: Will Deacon <will@...nel.org>
> ---
>  arch/powerpc/platforms/pseries/svm.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Thanks.

Acked-by: Michael Ellerman <mpe@...erman.id.au>


I assume Konrad will take this via the swiotlb tree?

cheers