From: <dan.j.williams@intel.com>
To: Aneesh Kumar K.V <aneesh.kumar@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
<linux-pci@vger.kernel.org>
Cc: <linux-coco@lists.linux.dev>, <bhelgaas@google.com>,
<yilun.xu@linux.intel.com>, <aik@amd.com>
Subject: Re: [PATCH 4/6] PCI/TSM: Add pci_tsm_bind() helper for instantiating TDIs
Date: Wed, 5 Nov 2025 13:49:52 -0800 [thread overview]
Message-ID: <690bc68082c76_74f7610077@dwillia2-mobl4.notmuch> (raw)
In-Reply-To: <yq5aecqdcbwa.fsf@kernel.org>
Aneesh Kumar K.V wrote:
[..]
> Can we set tdi in the constructor? I use it later as part of a bind()
> callback. I’d prefer not to pass tdi as an argument to those functions,
> since functions like do_dev_communicate() are reused in other contexts
> where tdi isn't needed.
I think if you need this it would be ok to set tsm->tdi in your driver.
It is not the greatest fit for pci_tsm_tdi_constructor() because that
function really does not know if the tdi is fully formed and ready to
publish via tsm->tdi. It only knows that the common fields have been
initialized. See below...
[..]
> modified drivers/pci/tsm.c
> @@ -391,8 +391,6 @@ int pci_tsm_bind(struct pci_dev *pdev, struct kvm *kvm, u32 tdi_id)
> if (IS_ERR(tdi))
> return PTR_ERR(tdi);
>
> - pdev->tsm->tdi = tdi;
> -
I think it is ok to keep this even if the TSM driver already did it.
> return 0;
> }
> EXPORT_SYMBOL_GPL(pci_tsm_bind);
> @@ -998,6 +996,7 @@ static struct pci_dev *find_dsm_dev(struct pci_dev *pdev)
> void pci_tsm_tdi_constructor(struct pci_dev *pdev, struct pci_tdi *tdi,
> struct kvm *kvm, u32 tdi_id)
> {
> + pdev->tsm->tdi = tdi;
> tdi->pdev = pdev;
> tdi->kvm = kvm;
> tdi->tdi_id = tdi_id;
This ordering potentially causes something that walks tdi->pdev to fail,
and who knows if the TSM driver calls pci_tsm_tdi_constructor() before
or after TSM driver specific init. It all around feels like the TSM
driver is responsible for making the "early publish" decision, not this
constructor.
next prev parent reply other threads:[~2025-11-05 21:50 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-05 4:00 [PATCH 0/6] PCI/TSM: Finalize "Link" TSM infrastructure Dan Williams
2025-11-05 4:00 ` [PATCH 1/6] resource: Introduce resource_assigned() for discerning active resources Dan Williams
2025-11-05 9:17 ` Jonathan Cameron
2025-11-05 21:57 ` dan.j.williams
2025-11-05 4:00 ` [PATCH 2/6] PCI/IDE: Add Address Association Register setup for downstream MMIO Dan Williams
2025-11-05 9:58 ` Jonathan Cameron
2025-11-05 23:04 ` dan.j.williams
2025-11-10 11:49 ` Jonathan Cameron
2025-11-05 4:00 ` [PATCH 3/6] PCI/IDE: Initialize an ID for all IDE streams Dan Williams
2025-11-05 15:27 ` Jonathan Cameron
2025-11-05 23:51 ` dan.j.williams
2025-11-10 11:52 ` Jonathan Cameron
2025-11-05 4:00 ` [PATCH 4/6] PCI/TSM: Add pci_tsm_bind() helper for instantiating TDIs Dan Williams
2025-11-05 4:59 ` Aneesh Kumar K.V
2025-11-05 21:49 ` dan.j.williams [this message]
2025-11-05 15:31 ` Jonathan Cameron
2025-11-06 0:11 ` dan.j.williams
2025-11-05 4:00 ` [PATCH 5/6] PCI/TSM: Add pci_tsm_guest_req() for managing TDIs Dan Williams
2025-11-05 15:38 ` Jonathan Cameron
2025-11-06 0:13 ` dan.j.williams
2025-11-05 4:00 ` [PATCH 6/6] PCI/TSM: Add 'dsm' and 'bound' attributes for dependent functions Dan Williams
2025-11-05 17:53 ` Jonathan Cameron
2025-11-13 12:10 ` Jonathan Cameron
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