linux-kernel - Re: [PATCH v3 0/3] arm64: realm: Fix DMA address for devices

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Message-ID: <20250311114519.GA4202@willie-the-truck>
Date: Tue, 11 Mar 2025 11:45:20 +0000
From: Will Deacon <will@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	linux-kernel@...r.kernel.org, maz@...nel.org, steven.price@....com,
	aneesh.kumar@...nel.org, gshan@...hat.com, robin.murphy@....com,
	linux-arm-kernel@...ts.infradead.org,
	Jean-Philippe Brucker <jean-philippe@...aro.org>,
	Christoph Hellwig <hch@....de>,
	Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH v3 0/3] arm64: realm: Fix DMA address for devices

On Thu, Mar 06, 2025 at 06:06:44PM +0000, Catalin Marinas wrote:
> On Thu, Mar 06, 2025 at 11:39:14AM +0000, Suzuki K Poulose wrote:
> > On 04/03/2025 13:40, Marek Szyprowski wrote:
> > > > On 27/02/2025 14:41, Suzuki K Poulose wrote:
> > > > > Linux can be run as a Confidential Guest in Arm CCA from Linux v6.13. The address
> > > > > space (GPA or IPA) of a Realm VM is split into two halves, with private bottom
> > > > > half and shared top half. In Linux we treat the "top" bit of the IPA space as
> > > > > an attribute, to indicate whether it is shared or not (MSB == 1 implies shared).
> > > > > Stage2 (GPA to PA) translations used by the CPU accesses, cover the full IPA space,
> > > > > and are managed by RMM. The "top" bit as attribute is only a software construct.
> [...]
> > > The changes look fine. However I won't be able to setup new dma-mapping
> > > git tree this week because I got really sick has to stay in bed. :/ If
> > > You don't want such delay, please merge it via ARM64 tree. Here is my:
> > 
> > Sorry to hear that. Hope you feel better soon.
> > 
> > > Acked-by: Marek Szyprowski <m.szyprowski@...sung.com>
> > 
> > Thanks Marek.
> > 
> > Btw, this series fixes the "Realm Guest" support for Linux, which was merged
> > in v6.13. To be precise, this should have :
> > 
> > Fixes: 42be24a4178f ("arm64: Enable memory encrypt for Realms")
> > 
> > Will/Catalin,
> > 
> > Please let me know if you would like me to send the series with
> > all the Acks, Reviews and mainly the Fixes tag added ?
> 
> We can add the acks and fixes tag, no worries. I can queue them for 6.15
> unless Will takes them as fixes for 6.14 (I'll wait for a bit).

For the series:

Acked-by: Will Deacon <will@...nel.org>

but I'd prefer this to land in 6.15 at this stage given that (a) it's
always been broken and (b) we're not exactly tripping over CCA-capable
hardware.

Cheers,

Will