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: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87o7t5ncat.ffs@tglx>
Date:   Thu, 17 Nov 2022 10:46:34 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Jason Gunthorpe <jgg@...dia.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Marc Zyngier <maz@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dave Jiang <dave.jiang@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Ashok Raj <ashok.raj@...el.com>, Jon Mason <jdmason@...zu.us>,
        Allen Hubbe <allenbh@...il.com>,
        "Ahmed S. Darwish" <darwi@...utronix.de>,
        Reinette Chatre <reinette.chatre@...el.com>
Subject: Re: [patch 27/33] genirq/msi: Provide constants for PCI/IMS support

On Wed, Nov 16 2022 at 15:54, Jason Gunthorpe wrote:
> On Fri, Nov 11, 2022 at 02:58:54PM +0100, Thomas Gleixner wrote:
>> +	/* Support for PCI/IMS */
>> +	MSI_FLAG_PCI_IMS		= (1 << 21),
>
> Maybe for legacy reasons it is too complicated, but it would be so
> much clearer of the special case of "I only know how to support PCI
> MSI and PCI MSI-X" was called out as a special flag, and the more
> general case of "any write_msg is fine by me" was left behind.
>
> I feel like when the device domain is created in the first place the
> parent domain(s) should be able to reject the creation if the
> requested child domain is not one it supports. Eg the hypervisor
> interactions checks if the child domain is PCI MSI or PCI MSI-X and
> rejects otherwise, because that is the only thing the hypervisor knows
> how to work with.
>
> If we did that perhaps we don't even need a flag or further checks?

It's not that simple. The flags are part of the domain creation sanity
checks and due to other constraints in our marvelous zoo of
architectures, iommus, hypervisors and whatever being explicit about
this is really required. Look at the GICv3-ITS voodoo which explicitly
needs to differentiate between PCI and non-PCI MSI. I wish we could
start from a clean slate, but that train has left the station long ago.

Thanks,

        tglx

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ