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From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-s390@vger.kernel.org, Mike Anderson <andmike@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Robin Murphy <robin.murphy@arm.com>,
	x86@kernel.org, Ram Pai <linuxram@us.ibm.com>,
	linux-kernel@vger.kernel.org, Halil Pasic <pasic@linux.ibm.com>,
	iommu@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	"Lendacky, Thomas" <thomas.lendacky@amd.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	linux-fsdevel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	linuxppc-dev@lists.ozlabs.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code
Date: Mon, 15 Jul 2019 17:14:04 -0300	[thread overview]
Message-ID: <875zo3njhv.fsf@morokweng.localdomain> (raw)
In-Reply-To: <20190715143039.GA6892@lst.de>


Christoph Hellwig <hch@lst.de> 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


  parent reply	other threads:[~2019-07-15 20:19 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-12  5:36 [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
2019-07-12  5:36 ` [PATCH 1/3] x86/Kconfig: Move ARCH_HAS_MEM_ENCRYPT to arch/Kconfig Thiago Jung Bauermann
2019-07-12 16:04   ` Thomas Gleixner
2019-07-12 23:35     ` Thiago Jung Bauermann
2019-07-12  5:36 ` [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files Thiago Jung Bauermann
2019-07-12  7:13   ` Christoph Hellwig
2019-07-12 23:42     ` Thiago Jung Bauermann
2019-07-12 16:09   ` Thomas Gleixner
2019-07-18 19:47     ` Thiago Jung Bauermann
2019-07-19  9:05   ` kbuild test robot
2019-07-20  0:22     ` Thiago Jung Bauermann
2019-07-12  5:36 ` [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code Thiago Jung Bauermann
2019-07-12 13:09   ` Halil Pasic
2019-07-12 14:08     ` Christoph Hellwig
2019-07-12 14:51       ` Halil Pasic
2019-07-12 15:11         ` Christoph Hellwig
2019-07-12 15:42           ` Halil Pasic
2019-07-13  8:08             ` Christoph Hellwig
2019-07-12 21:55     ` Thiago Jung Bauermann
2019-07-15 14:03       ` Halil Pasic
2019-07-15 14:30         ` Christoph Hellwig
2019-07-15 15:44           ` Lendacky, Thomas
2019-07-15 20:14           ` Thiago Jung Bauermann [this message]
2019-07-13  4:45 [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
2019-07-13  4:45 ` [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code Thiago Jung Bauermann

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