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From: Jason Gunthorpe <jgg@nvidia.com>
To: Alexey Kardashevskiy <aik@amd.com>
Cc: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>,
	linux-coco@lists.linux.dev, iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Bjorn Helgaas <helgaas@kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	Jonathan Cameron <jic23@kernel.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Nicolin Chen <nicolinc@nvidia.com>,
	Samuel Ortiz <sameo@rivosinc.com>,
	Steven Price <steven.price@arm.com>,
	Suzuki K Poulose <Suzuki.Poulose@arm.com>,
	Will Deacon <will@kernel.org>,
	Xu Yilun <yilun.xu@linux.intel.com>,
	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC PATCH v6 09/11] iommufd: Add the vdevice TSM request ioctl
Date: Thu, 22 Oct 2026 09:30:58 -0300	[thread overview]
Message-ID: <20261022123058.GC3008132@nvidia.com> (raw)
In-Reply-To: <d9304f91-2371-460b-8616-15a4f96c5674@amd.com>

On Thu, Oct 22, 2026 at 06:16:04PM +1100, Alexey Kardashevskiy wrote:
> > > [ ... 34 lines skipped ... ]
> > > +/**
> > > + * enum iommu_vdevice_tsm_guest_req_op - operation for guest TSM requests
> > > + * @TSM_REQ_VALIDATE_MMIO: Validate MMIO for the TDI
> > > + * @TSM_REQ_SET_TDI_STATE: Set TDI state
> > > + * @TSM_REQ_SEV_ENABLE_DMA: Enable SEV DMA
> > 
> > That seems wrong.. The hypervisor should not have control over T=1
> > DMA.
> 
> This is a guest request to the PSP which does control T=1, the HV is
> forwarding it and does some extra stuff while there. Probably could
> be decoupled and go to a separate ioctl().

Presumably the guest request is encrypted/authenticated somehow?
Otherwise it is security broken if the host can forge a T=1 control.

If that's so this should just be some AMD_PSP_AUTHENTICATED_COMMAND it
doesn't need more detail?

Also, reminder, since none of this is actually multi-vendor before
anything goes into the uapi header it needs a concrete public spec
reference to what exactly it is carrying through the uAPI.

Jason

  reply	other threads:[~2026-10-22 12:31 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-17 14:01 [RFC PATCH v6 00/11] iommufd: Infrastructure for vIOMMU creation for confidential guests and guest TSM requests Aneesh Kumar K.V (Arm)
2026-09-17 14:01 ` [RFC PATCH v6 01/11] vfio: cache KVM VM file references instead of raw struct kvm pointers Aneesh Kumar K.V (Arm)
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-30  7:19     ` Aneesh Kumar K.V
2026-09-17 14:01 ` [RFC PATCH v6 02/11] vfio: cdev: Reject duplicate bind before updating KVM file Aneesh Kumar K.V (Arm)
2026-09-24  7:53   ` Tian, Kevin
2026-09-25  5:49     ` Aneesh Kumar K.V
2026-09-17 14:01 ` [RFC PATCH v6 03/11] iommufd/device: Associate KVM file pointer with iommufd_device Aneesh Kumar K.V (Arm)
2026-09-17 14:01 ` [RFC PATCH v6 04/11] iommufd/viommu: Keep a reference to the KVM file Aneesh Kumar K.V (Arm)
2026-09-30 13:28   ` Vasant Hegde
2026-10-02  5:26     ` Aneesh Kumar K.V
2026-09-17 14:01 ` [RFC PATCH v6 05/11] iommu: Add a helper to validate a vIOMMU parent Aneesh Kumar K.V (Arm)
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-25  5:48     ` Aneesh Kumar K.V
2026-09-25 12:23       ` Jason Gunthorpe
2026-09-28 10:36         ` Aneesh Kumar K.V
2026-09-28 12:11           ` Jason Gunthorpe
2026-09-28 15:39             ` Aneesh Kumar K.V
2026-09-28 16:17               ` Jason Gunthorpe
2026-09-28 18:08                 ` Jacob Pan
2026-09-28 18:20                   ` Jason Gunthorpe
2026-09-28 22:24                     ` Jacob Pan
2026-09-28 23:03                       ` Jason Gunthorpe
2026-09-29  5:55                         ` Jacob Pan
2026-09-29 12:30                           ` Jason Gunthorpe
2026-09-29 23:15                             ` Jacob Pan
2026-09-29 23:30                               ` Jason Gunthorpe
2026-09-17 14:01 ` [RFC PATCH v6 06/11] iommu: Add a helper to query vIOMMU hardware parameters Aneesh Kumar K.V (Arm)
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-25  5:59     ` Aneesh Kumar K.V
2026-09-25 12:29       ` Jason Gunthorpe
2026-09-17 14:01 ` [RFC PATCH v6 07/11] coco: tsm: Expose active-user lifetime references Aneesh Kumar K.V (Arm)
2026-09-17 14:01 ` [RFC PATCH v6 08/11] iommufd: Add vIOMMU provider support Aneesh Kumar K.V (Arm)
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-25  6:08     ` Aneesh Kumar K.V
2026-09-25 12:39       ` Jason Gunthorpe
2026-09-28  3:41         ` Tian, Kevin
2026-09-29  6:14           ` Aneesh Kumar K.V
2026-09-29 12:17             ` Jason Gunthorpe
2026-09-29 12:45               ` Aneesh Kumar K.V
2026-09-29 13:06                 ` Jason Gunthorpe
2026-09-29 15:58                   ` Aneesh Kumar K.V
2026-09-29 19:10                     ` Jason Gunthorpe
2026-09-28 10:51         ` Aneesh Kumar K.V
2026-09-17 14:01 ` [RFC PATCH v6 09/11] iommufd: Add the vdevice TSM request ioctl Aneesh Kumar K.V (Arm)
2026-09-18 13:09   ` Alexey Kardashevskiy
2026-09-18 13:13     ` Jason Gunthorpe
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-30  8:03     ` Aneesh Kumar K.V
2026-09-30 13:26       ` Vasant Hegde
2026-09-30 14:03         ` Jason Gunthorpe
2026-09-30 14:08       ` Jason Gunthorpe
2026-10-22  7:16     ` Alexey Kardashevskiy
2026-10-22 12:30       ` Jason Gunthorpe [this message]
2026-09-17 14:01 ` [RFC PATCH v6 10/11] PCI/TSM: Remove the legacy guest request interface Aneesh Kumar K.V (Arm)
2026-09-17 14:01 ` [RFC PATCH v6 11/11] PCI/TSM: Add reference-counted contexts for vdevice providers Aneesh Kumar K.V (Arm)
2026-09-24  8:17   ` Tian, Kevin
2026-09-24 19:41   ` Jason Gunthorpe
2026-09-25  8:15     ` Aneesh Kumar K.V
2026-09-28 18:47   ` Sonang Patel
2026-09-28 23:08     ` Jason Gunthorpe
2026-10-02  6:14       ` Aneesh Kumar K.V
2026-10-02 13:06         ` Jason Gunthorpe
2026-09-17 14:17 ` [RFC PATCH v6 00/11] iommufd: Infrastructure for vIOMMU creation for confidential guests and guest TSM requests Aneesh Kumar K.V
2026-09-24  7:48 ` Tian, Kevin
2026-09-24 19:20   ` Jason Gunthorpe
2026-09-28  3:35     ` Tian, Kevin
2026-09-28 13:08       ` Jason Gunthorpe
2026-09-25  8:29   ` Aneesh Kumar K.V
2026-09-28  3:41     ` Tian, Kevin
2026-09-28  3:55       ` Tian, Kevin
2026-09-24 19:09 ` Jason Gunthorpe
2026-09-25  6:46   ` Aneesh Kumar K.V
2026-09-25 12:45     ` Jason Gunthorpe

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