[lkml]   [2019]   [Jul]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code

Christoph Hellwig <> writes:

> On Mon, Jul 15, 2019 at 04:03:17PM +0200, Halil Pasic wrote:
>> > I thought about that but couldn't put my finger on a general concept.
>> > Is it "guest with memory inaccessible to the host"?
>> >
>> Well, force_dma_unencrypted() is a much better name thatn sev_active():
>> s390 has no AMD SEV, that is sure, but for virtio to work we do need to
>> make our dma accessible to the hypervisor. Yes, your "guest with memory
>> inaccessible to the host" shows into the right direction IMHO.
>> Unfortunately I don't have too many cycles to spend on this right now.
> In x86 it means that we need to remove dma encryption using
> set_memory_decrypted before using it for DMA purposes. In the SEV
> case that seems to be so that the hypervisor can access it, in the SME
> case that Tom just fixes it is because there is an encrypted bit set
> in the physical address, and if the device doesn't support a large
> enough DMA address the direct mapping code has to encrypt the pages
> used for the contigous allocation.
>> Being on cc for your patch made me realize that things got broken on
>> s390. Thanks! I've sent out a patch that fixes protvirt, but we are going
>> to benefit from your cleanups. I think with your cleanups and that patch
>> of mine both sev_active() and sme_active() can be removed. Feel free to
>> do so. If not, I can attend to it as well.
> Yes, I think with the dma-mapping fix and this series sme_active and
> sev_active should be gone from common code. We should also be able
> to remove the exports x86 has for them.
> I'll wait a few days and will then feed the dma-mapping fix to Linus,
> it might make sense to either rebase Thiagos series on top of the
> dma-mapping for-next branch, or wait a few days before reposting.

I'll rebase on top of dma-mapping/for-next and do the break up of patch
2 that you mentioned as well.

Thiago Jung Bauermann
IBM Linux Technology Center

 \ /
  Last update: 2019-07-15 22:15    [W:0.049 / U:28.452 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site