From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f42.google.com (mail-qv1-f42.google.com [209.85.219.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8425F3CCA05 for ; Mon, 27 Apr 2026 13:49:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777297749; cv=none; b=laNvIgECB25GBvZgw1Pd2vL12SFMWD8SinWLE01Ua/VcxSQ0Gb7CiZel7zMES9grNFKG4nOYRc/oJ8sxNlyCGA0mtcNO3S8VBkFOvPBlPHLaXfrOzf3AYHe0paNLtgdt0cucYSXJUxeuzjnYoaufaTw/VRXm8s8SLEm+O9KjyXU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777297749; c=relaxed/simple; bh=AiaEXL2vP7Re9WDbKnigCW6bt2LfZHNbeafJta6NglE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PYa9nkIbvXBbsfVg5zVXI8psuDWgyzL1dO6Qx4MTYgy16Qx2q4qJEn0t+I0ZrCYF/IDQIJo7F5scfEjhLYG290jZKNsxy8OyzgcLH/QSytteoj4wV5YscMS9U0C9S+fETLW1XZOEf16h/B8pB35X0x0McDvaaMI9+3EdfcQnvc8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=lxR1sGjh; arc=none smtp.client-ip=209.85.219.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="lxR1sGjh" Received: by mail-qv1-f42.google.com with SMTP id 6a1803df08f44-8acb3dab8dfso64062616d6.1 for ; Mon, 27 Apr 2026 06:49:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1777297745; x=1777902545; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=8PYGlOXEG6E9/P2t0qYpdnkfCSnyFBuw0mLKh5MPI4E=; b=lxR1sGjhW4Y7GT3xcWDKd4qw+q7dLoiH9nUJGQmDkYy5aksQ0xEqXQm5hBewaAN9t5 +HVdnsVBKM4VK1CorWgR3CSqImBLIYcyZ9LufuZeyOM4sSXcxuO516cb8kqFfKwVN5We 7a8ze9ZNWnK+YGAJ2xakcFHKRbc4iI+m63z14hrOQeCg4fhTUsREobCH6Nx+mBvyFHJl qthltrRTkccUiqDOg/8yh9dgq182jNKWZF7iLHjYGadwldFku/IxnE1AZLI1t3egNdiD LSdO9Gpzlv/b7JDOsTWbTX/VGJXQp/DDQtrAWdHikzrIJTKWiq68IcWcxaIDW++fQH46 DihQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777297745; x=1777902545; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8PYGlOXEG6E9/P2t0qYpdnkfCSnyFBuw0mLKh5MPI4E=; b=n8iNkQCJinTyoxFuZrc403wplxNfVQcwVbd0GayUEYOuaiC1UINXGeRMpCZsqGStMM 12JAJJH20cmpQa4vtHNMG9kgq5O9m7lHg74xIvU7JahWpZewLtuhSvV+R0uX9qJ3g+HV 5Z5oCGVNfxGtoo+nRx4guwQDdwaQzvxsoZdpzls7y32LN6QI7aFqV5pddfwYiXAxUCVj Hzw+m0tgl1TgrQipXOk4IVi/WpNJuitTkHiGdxNUQSmXMiv1K7OhcG/gDdz9iwITRDF9 rSsgwcC1JVXAWtQnfC4JOvjr6JUHXLqfrdjt6ea2Bgvy4ALvORicfBvSMORZApk2XtTe v7zQ== X-Forwarded-Encrypted: i=1; AFNElJ8BrEqin/b91leDT2MWuv739KF9DD+NYss04hD9auzZXrUjolhVNL7BKktAVMx/n/2e5upmxBA=@lists.linux.dev X-Gm-Message-State: AOJu0YxdQy0F0wfxwQL1PtH5GO0tcqJtyJ3GEyzGCggVpX0YmN5UF+Xf Q+hXl1ldxlut4FhWZuRj2jmonZQhz++xNlNeFau7PSwNj7I6CT17ILCrPxTgQpgqu2o= X-Gm-Gg: AeBDievKSShgxJ8hE2n4v5tI+LoIJ8ZW0+lc+uwIhStsTrNQqiX/Rfvy6tOU7H/Nj6U JCanvgJ+dNDwoVY1mU0K3zphRJXflXigXnMA63QEGhw7UCPoo9WlWci1TppmZmzLiELQxY0bDF1 luWDwqWu6DBdoT1d0es6W0Ssd3A69SiOmFyw8ngMHj9Zjtp+RzBXm7UMGlHjPzFfI9hq6bf4llB Xx3Ob4JZLXjio53USk4tEZ3IUsDTcZBEvzQWO8m8Ea2uEGWQcvuRqxwn42hiPOGmvmqb32sDr3b uwNJ0PHwhsK+xaTDoV5JZLkQdFJO2cXyZCfrkpnwUKgjqShm3TobIUgQzoIXY98vmErneZYtnad DebOPz2JYlY2K0fwgoWkXNcZBvxCWRDF2OPpyXgLvltT1Z+2F9LiTEgQitu2WEZVWFn79GQ9LV+ xt5dO6Us9aEf35kGGXEWBkQSg992jDEbq9I7Bd//Kpe2YtnGpoyTpy90GW72zdE5VmHMPeYXn3M MK2A3cmHeX1iBBf X-Received: by 2002:a05:6214:6107:b0:8a5:bd5b:e5f with SMTP id 6a1803df08f44-8b02817a4a5mr537295746d6.51.1777297745279; Mon, 27 Apr 2026 06:49:05 -0700 (PDT) Received: from ziepe.ca (crbknf0213w-47-54-130-67.pppoe-dynamic.high-speed.nl.bellaliant.net. [47.54.130.67]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8b02aa4f1f9sm257474006d6.0.2026.04.27.06.49.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2026 06:49:04 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wHMKd-00000003T5r-43dX; Mon, 27 Apr 2026 10:49:03 -0300 Date: Mon, 27 Apr 2026 10:49:03 -0300 From: Jason Gunthorpe To: "Aneesh Kumar K.V (Arm)" Cc: linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, Catalin Marinas , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Suzuki K Poulose , Thomas Gleixner , Will Deacon Subject: Re: [PATCH v4 2/3] swiotlb: dma: its: Enforce host page-size alignment for shared buffers Message-ID: <20260427134903.GA740385@ziepe.ca> References: <20260427063108.909019-1-aneesh.kumar@kernel.org> <20260427063108.909019-3-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260427063108.909019-3-aneesh.kumar@kernel.org> On Mon, Apr 27, 2026 at 12:01:07PM +0530, Aneesh Kumar K.V (Arm) wrote: > When running private-memory guests, the guest kernel must apply additional > constraints when allocating buffers that are shared with the hypervisor. This patch has way too much stuff in it. I think your patch structure should be changed around 1) Patch to add mem_decrypt_granule_size(), and explain it as the alignment & size of what can be passed to set_memory_encrypted/decrypted() 2) Add support for mem_decrypt_granule_size() to ARM Then patches going caller by caller of set_memory_decrypted() to make them follow the new rule: 3) its 4) swiotlb 3) dma_alloc_coherent etc. don't forget about the new dma buf heaps too: drivers/dma-buf/heaps/system_heap.c: ret = set_memory_decrypted(addr, nr_pages); It is worth calling out in the cover letter that all the ARM CCA relevant places are fixed but drivers/hv/ is left for future. > @@ -33,18 +32,30 @@ int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops) > > int set_memory_encrypted(unsigned long addr, int numpages) > { > - if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) > + if (likely(!crypt_ops)) > return 0; > > + if (WARN_ON(!IS_ALIGNED(addr, mem_decrypt_granule_size()))) > + return -EINVAL; > + > + if (WARN_ON(!IS_ALIGNED(numpages << PAGE_SHIFT, mem_decrypt_granule_size()))) > + return -EINVAL; > + > return crypt_ops->encrypt(addr, numpages); > } > EXPORT_SYMBOL_GPL(set_memory_encrypted); > > int set_memory_decrypted(unsigned long addr, int numpages) > { > - if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) > + if (likely(!crypt_ops)) > return 0; > > + if (WARN_ON(!IS_ALIGNED(addr, mem_decrypt_granule_size()))) > + return -EINVAL; > + > + if (WARN_ON(!IS_ALIGNED(numpages << PAGE_SHIFT, mem_decrypt_granule_size()))) > + return -EINVAL; > + > return crypt_ops->decrypt(addr, numpages); > } > EXPORT_SYMBOL_GPL(set_memory_decrypted); This should go in the ARM patch adding mem_decrypt_granule_size() to CCA > diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h > index 07584c5e36fb..1e01c9ac697f 100644 > --- a/include/linux/mem_encrypt.h > +++ b/include/linux/mem_encrypt.h > @@ -11,6 +11,8 @@ > #define __MEM_ENCRYPT_H__ > > #ifndef __ASSEMBLY__ > +#include > +#include > > #ifdef CONFIG_ARCH_HAS_MEM_ENCRYPT > > @@ -54,6 +56,18 @@ > #define dma_addr_canonical(x) (x) > #endif > > +#ifndef mem_decrypt_granule_size > +static inline size_t mem_decrypt_granule_size(void) > +{ > + return PAGE_SIZE; > +} > +#endif > + > +static inline size_t mem_decrypt_align(size_t size) > +{ > + return ALIGN(size, mem_decrypt_granule_size()); > +} > + > #endif /* __ASSEMBLY__ */ > > #endif /* __MEM_ENCRYPT_H__ */ I know it seems a bit small, but put this in its own patch and explain how it works. I'd also like to see a kdoc here, and add a kdoc to set_memory_decrypted() that links back so people have a better chance to know about this. Jason