From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alexey Kardashevskiy <aik@amd.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, linux-pci@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Dan Williams <dan.j.williams@intel.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Mike Rapoport <rppt@kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Ard Biesheuvel <ardb@kernel.org>,
Ashish Kalra <ashish.kalra@amd.com>,
Stefano Garzarella <sgarzare@redhat.com>,
Melody Wang <huibo.wang@amd.com>,
Seongman Lee <augustus92@kaist.ac.kr>,
Joerg Roedel <joerg.roedel@amd.com>,
Nikunj A Dadhania <nikunj@amd.com>,
Michael Roth <michael.roth@amd.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Andi Kleen <ak@linux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Denis Efremov <efremov@linux.com>,
Geliang Tang <geliang@kernel.org>,
Piotr Gregor <piotrgregor@rsyncme.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Alex Williamson <alex@shazbot.org>, Arnd Bergmann <arnd@arndb.de>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Yinghai Lu <yinghai@kernel.org>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>,
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>,
Xu Yilun <yilun.xu@linux.intel.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Kim Phillips <kim.phillips@amd.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Claire Chang <tientzu@chromium.org>,
linux-coco@lists.linux.dev, iommu@lists.linux.dev,
Jiri Pirko <jiri@resnulli.us>
Subject: Re: [PATCH kernel 6/9] x86/dma-direct: Stop changing encrypted page state for TDISP devices
Date: Tue, 3 Mar 2026 08:15:08 -0400 [thread overview]
Message-ID: <20260303121508.GD964116@ziepe.ca> (raw)
In-Reply-To: <9cf2e2e6-0fe2-4804-9c62-bc60c89d57c1@amd.com>
On Tue, Mar 03, 2026 at 07:19:36PM +1100, Alexey Kardashevskiy wrote:
> > It seems from your email that the CPU S2 has the Cbit as part of the
> > address and the S1 feeds it through to the S2, so it is genuinely has
> > two addres spaces?
>
> S1/S2 PTEs have Cbit. Addresses to look up those PTEs - do not.
So we are back to what I was saying before: using phys_addr_t to
encode a PTE bit is probably a very confusing idea - especially when
contrasted with the other arches that have a legitimate address bit.
> > Same way it knows if there is no S1?
>
> If no S1 - then sDTE decides on Cbit for the entire ASID (with the help of vTOM).
Sounds like the intention was the IOMMU shared/private space would be
controlled with vTOM which actually does a create a legitimate address
bit in the phys_addr_t.
A sDTE global control is OK for non-TDISP devices, or even devices
that haven't entered RUN yet, but it is not OK for a TDISP device that
must still be able to access shared memory.
> I understand I am often confusing, trying to unconfuse (including myself)... Thanks,
It seems to me the AMD architecture itself is pretty confusing. :\
Jason
next prev parent reply other threads:[~2026-03-03 12:15 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 5:37 [PATCH kernel 0/9] PCI/TSM: coco/sev-guest: Implement SEV-TIO PCIe TDISP (phase2) Alexey Kardashevskiy
2026-02-25 5:37 ` [PATCH kernel 1/9] pci/tsm: Add TDISP report blob and helpers to parse it Alexey Kardashevskiy
2026-02-25 6:16 ` dan.j.williams
2026-02-25 10:10 ` Arnd Bergmann
2026-02-26 0:09 ` Alexey Kardashevskiy
2026-02-26 2:34 ` dan.j.williams
2026-02-26 3:49 ` Alexey Kardashevskiy
2026-02-26 21:08 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 2/9] pci/tsm: Add tsm_tdi_status Alexey Kardashevskiy
2026-02-25 6:33 ` dan.j.williams
2026-02-25 23:42 ` Alexey Kardashevskiy
2026-03-02 6:58 ` Aneesh Kumar K.V
2026-02-25 5:37 ` [PATCH kernel 3/9] coco/sev-guest: Allow multiple source files in the driver Alexey Kardashevskiy
2026-02-25 5:37 ` [PATCH kernel 4/9] dma/swiotlb: Stop forcing SWIOTLB for TDISP devices Alexey Kardashevskiy
2026-02-25 16:30 ` dan.j.williams
2026-02-25 18:00 ` Robin Murphy
2026-02-25 20:57 ` dan.j.williams
2026-02-28 0:28 ` Jason Gunthorpe
2026-03-02 23:53 ` dan.j.williams
2026-03-03 0:19 ` Jason Gunthorpe
2026-03-03 0:29 ` dan.j.williams
2026-03-03 12:43 ` Jason Gunthorpe
2026-03-04 6:45 ` Alexey Kardashevskiy
2026-03-04 12:43 ` Jason Gunthorpe
2026-03-25 10:42 ` Alexey Kardashevskiy
2026-04-03 12:40 ` Alexey Kardashevskiy
2026-04-15 6:32 ` Alexey Kardashevskiy
2026-04-20 23:50 ` Jason Gunthorpe
2026-04-30 3:25 ` Alexey Kardashevskiy
2026-02-25 16:48 ` Robin Murphy
2026-02-26 0:09 ` Alexey Kardashevskiy
2026-03-02 7:54 ` Aneesh Kumar K.V
2026-02-25 5:37 ` [PATCH kernel 5/9] x86/mm: Stop forcing decrypted page state " Alexey Kardashevskiy
2026-02-25 16:51 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 6/9] x86/dma-direct: Stop changing encrypted " Alexey Kardashevskiy
2026-02-25 17:08 ` Robin Murphy
2026-02-25 21:35 ` dan.j.williams
2026-02-26 6:22 ` Alexey Kardashevskiy
2026-02-28 0:06 ` Jason Gunthorpe
2026-03-02 0:01 ` Alexey Kardashevskiy
2026-03-02 0:35 ` Jason Gunthorpe
2026-03-02 5:26 ` Alexey Kardashevskiy
2026-03-02 13:35 ` Jason Gunthorpe
2026-03-03 8:19 ` Alexey Kardashevskiy
2026-03-03 12:15 ` Jason Gunthorpe [this message]
2026-02-25 5:37 ` [PATCH kernel 7/9] coco/sev-guest: Implement the guest support for SEV TIO (phase2) Alexey Kardashevskiy
2026-02-25 6:00 ` Borislav Petkov
2026-02-26 3:39 ` Alexey Kardashevskiy
2026-02-26 19:52 ` Borislav Petkov
2026-02-25 5:37 ` [PATCH kernel 8/9] RFC: PCI: Avoid needless touching of Command register Alexey Kardashevskiy
2026-02-26 0:24 ` Bjorn Helgaas
2026-02-26 5:58 ` Alexey Kardashevskiy
2026-02-26 0:34 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 9/9] pci: Allow encrypted MMIO mapping via sysfs Alexey Kardashevskiy
2026-03-02 8:20 ` Aneesh Kumar K.V
2026-03-02 8:59 ` Alexey Kardashevskiy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260303121508.GD964116@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=aik@amd.com \
--cc=ak@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=alex@shazbot.org \
--cc=aneesh.kumar@kernel.org \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=ashish.kalra@amd.com \
--cc=augustus92@kaist.ac.kr \
--cc=bhelgaas@google.com \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=dwmw@amazon.co.uk \
--cc=efremov@linux.com \
--cc=geliang@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=herbert@gondor.apana.org.au \
--cc=hpa@zytor.com \
--cc=huibo.wang@amd.com \
--cc=iommu@lists.linux.dev \
--cc=jacob.jun.pan@linux.intel.com \
--cc=jbarnes@virtuousgeek.org \
--cc=jiri@resnulli.us \
--cc=joerg.roedel@amd.com \
--cc=jonathan.cameron@huawei.com \
--cc=kevin.brodsky@arm.com \
--cc=kim.phillips@amd.com \
--cc=konrad.wilk@oracle.com \
--cc=kvm@vger.kernel.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=luto@kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=michael.roth@amd.com \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=mst@redhat.com \
--cc=nikunj@amd.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=piotrgregor@rsyncme.org \
--cc=robin.murphy@arm.com \
--cc=rppt@kernel.org \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=seanjc@google.com \
--cc=sgarzare@redhat.com \
--cc=sstabellini@kernel.org \
--cc=suravee.suthikulpanit@amd.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=tientzu@chromium.org \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
--cc=yilun.xu@linux.intel.com \
--cc=yinghai@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.