From: Jason Gunthorpe <jgg@ziepe.ca>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>,
linux-coco@lists.linux.dev, kvmarm@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
Marc Zyngier <maz@kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
Steven Price <steven.price@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Thomas Gleixner <tglx@kernel.org>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v6 0/9] coco: guest: Enforce host page-size alignment for shared buffers
Date: Fri, 18 Sep 2026 13:57:54 -0300 [thread overview]
Message-ID: <20260918165754.GG11599@ziepe.ca> (raw)
In-Reply-To: <aq1sT2EDsGaomqST@arm.com>
On Fri, Sep 18, 2026 at 05:52:31PM +0100, Catalin Marinas wrote:
> TBH, I'm tempted not to support this configuration at all, just fail
> gracefully if the realm page size doesn't match the host's. However, if
> that's a real world configuration,
realm != host is going to be fairly common.
host > realm is probably not that common, I would guess.
> I wonder whether could we leverage the swiotlb mechanism but with a
> separate io_tlb_mem as a shared coco allocator with the right
> alignment and use this pool when force_dma_unencrypted() instead of
> specific alloc_pages() with adjusted order.
I propose we fix the far too low level set memory decrypted apis into
proper allocators, with APIs that can handle a round up. Then see
where we end up after that.
If we can hide 90% of it in an allocator then lets see if we can open
code the rest.
Jason
next prev parent reply other threads:[~2026-09-18 16:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 10:34 Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 1/9] mm/mem_encrypt: Add helpers for shared-buffer alignment Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 2/9] irqchip/gic-v3-its: Align shared ITS allocations to the CoCo shared granule size Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 3/9] dma-mapping: Pass allocation attrs to contiguous allocation helpers Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 4/9] dma-direct: Align CoCo shared DMA allocations to the shared granule size Aneesh Kumar K.V (Arm)
2026-09-18 14:16 ` Catalin Marinas
2026-09-04 10:34 ` [PATCH v6 5/9] swiotlb: Align shared IO TLB pools " Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 6/9] swiotlb: Reject misaligned restricted DMA pools for CoCo guests Aneesh Kumar K.V (Arm)
2026-09-04 10:34 ` [PATCH v6 7/9] dma-buf: system_heap: Enforce shared-granule alignment for cc-shared buffers Aneesh Kumar K.V (Arm)
2026-09-18 15:16 ` Catalin Marinas
2026-09-18 15:23 ` Christian König
2026-09-18 15:36 ` Jason Gunthorpe
2026-09-18 15:39 ` Christian König
2026-09-18 16:53 ` Jason Gunthorpe
2026-09-04 10:34 ` [PATCH v6 8/9] arm64: realm: Add RHI helper to query IPA state change alignment Aneesh Kumar K.V (Arm)
2026-09-16 16:12 ` Suzuki K Poulose
2026-09-18 10:39 ` Aneesh Kumar K.V
2026-09-04 10:34 ` [PATCH v6 9/9] arm64: realm: Expose the CCA shared granule size through mem_encrypt ops Aneesh Kumar K.V (Arm)
2026-09-16 16:17 ` Suzuki K Poulose
2026-09-18 16:52 ` [PATCH v6 0/9] coco: guest: Enforce host page-size alignment for shared buffers Catalin Marinas
2026-09-18 16:57 ` Jason Gunthorpe [this message]
2026-09-18 17:10 ` Catalin Marinas
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