linux-kernel - Re: [PATCH v2] PCI: Support Immediate Readiness on devices without PM capabilities

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20250722230321.GA2861805@bhelgaas>
Date: Tue, 22 Jul 2025 18:03:21 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, David Matlack <dmatlack@...gle.com>,
	Vipin Sharma <vipinsh@...gle.com>,
	Aaron Lewis <aaronlewis@...gle.com>
Subject: Re: [PATCH v2] PCI: Support Immediate Readiness on devices without
 PM capabilities

On Tue, Jul 22, 2025 at 08:59:26AM -0700, Sean Christopherson wrote:
> Query support for Immediate Readiness irrespective of whether or not the
> device supports PM capabilities, as nothing in the PCIe spec suggests that
> Immediate Readiness is in any way dependent on PM functionality.
> 
> Fixes: d6112f8def51 ("PCI: Add support for Immediate Readiness")
> Cc: David Matlack <dmatlack@...gle.com>
> Cc: Vipin Sharma <vipinsh@...gle.com>
> Cc: Aaron Lewis <aaronlewis@...gle.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Applied to pci/enumeration for v6.17, thanks!

> ---
> 
> v2: Move logic to pci_init_capabilities() instead of piggybacking the
>     PM initialization code. [Vipin, Bjorn]
> 
> v1 [RFC]:  https://lore.kernel.org/all/20250624171637.485616-1-seanjc@google.com
> 
>  drivers/pci/pci.c   |  4 ----
>  drivers/pci/probe.c | 10 ++++++++++
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 9e42090fb108..4a1ba5c017cd 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3205,7 +3205,6 @@ void pci_pm_power_up_and_verify_state(struct pci_dev *pci_dev)
>  void pci_pm_init(struct pci_dev *dev)
>  {
>  	int pm;
> -	u16 status;
>  	u16 pmc;
>  
>  	device_enable_async_suspend(&dev->dev);
> @@ -3266,9 +3265,6 @@ void pci_pm_init(struct pci_dev *dev)
>  		pci_pme_active(dev, false);
>  	}
>  
> -	pci_read_config_word(dev, PCI_STATUS, &status);
> -	if (status & PCI_STATUS_IMM_READY)
> -		dev->imm_ready = 1;
>  poweron:
>  	pci_pm_power_up_and_verify_state(dev);
>  	pm_runtime_forbid(&dev->dev);
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 4b8693ec9e4c..d33b8af37247 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2595,6 +2595,15 @@ void pcie_report_downtraining(struct pci_dev *dev)
>  	__pcie_print_link_status(dev, false);
>  }
>  
> +static void pci_imm_ready_init(struct pci_dev *dev)
> +{
> +	u16 status;
> +
> +	pci_read_config_word(dev, PCI_STATUS, &status);
> +	if (status & PCI_STATUS_IMM_READY)
> +		dev->imm_ready = 1;
> +}
> +
>  static void pci_init_capabilities(struct pci_dev *dev)
>  {
>  	pci_ea_init(dev);		/* Enhanced Allocation */
> @@ -2604,6 +2613,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
>  	/* Buffers for saving PCIe and PCI-X capabilities */
>  	pci_allocate_cap_save_buffers(dev);
>  
> +	pci_imm_ready_init(dev);	/* Immediate Ready */
>  	pci_pm_init(dev);		/* Power Management */
>  	pci_vpd_init(dev);		/* Vital Product Data */
>  	pci_configure_ari(dev);		/* Alternative Routing-ID Forwarding */
> 
> base-commit: 89be9a83ccf1f88522317ce02f854f30d6115c41
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
>