linux-kernel - Re: [patch 0/7] x86/pci: Switch to lockless ECAM configuration mode

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]

Date:   Mon, 12 Jun 2017 17:25:36 -0700
From:   Andi Kleen <ak@...ux.intel.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <helgaas@...nel.org>, x86@...nel.org,
        Peter Anvin <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [patch 0/7] x86/pci: Switch to lockless ECAM configuration mode

On Thu, Mar 16, 2017 at 10:50:02PM +0100, Thomas Gleixner wrote:
> Andi reported that the Intel Uncore performance monitoring suffers from the
> global pci_lock which protects the generic PCI config space accessors.
> 
> This lock can be removed on X86 because all architecture specific config
> space accessors are either serialized by a seperate lock or can be
> converted to have their own locking. The mmconfig based access (ECAM) does
> not require serialization at the config read/write level because the access
> is a simple byte/word/dword read from or write to the memory mapped
> configuration space. In that case the lock does not provide any more
> protection than the hardware provides already.
> 
> The series converts the CE4100 PCI low level accessors to use the x86
> specific pci_config_lock and implements the switch over to lockless ECAM
> configureation space accesors when the system is capable.

What's the status of this patch series? The lock contention
problem is still there.

Thanks,

-Andi