netdev - Re: [PATCH v3 09/14] x86/xen/msr: Remove calling native_{read,write}_msr{,_safe}() in pmu_msr

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: <524349a7-55da-42a2-b9cc-ec0d2ce66ae4@suse.com>
Date: Fri, 25 Apr 2025 11:55:12 +0200
From: Jürgen Groß <jgross@...e.com>
To: "Xin Li (Intel)" <xin@...or.com>, linux-kernel@...r.kernel.org,
 kvm@...r.kernel.org, linux-perf-users@...r.kernel.org,
 linux-hyperv@...r.kernel.org, virtualization@...ts.linux.dev,
 linux-pm@...r.kernel.org, linux-edac@...r.kernel.org,
 xen-devel@...ts.xenproject.org, linux-acpi@...r.kernel.org,
 linux-hwmon@...r.kernel.org, netdev@...r.kernel.org,
 platform-driver-x86@...r.kernel.org
Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com, acme@...nel.org,
 andrew.cooper3@...rix.com, peterz@...radead.org, namhyung@...nel.org,
 mark.rutland@....com, alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
 irogers@...gle.com, adrian.hunter@...el.com, kan.liang@...ux.intel.com,
 wei.liu@...nel.org, ajay.kaher@...adcom.com,
 bcm-kernel-feedback-list@...adcom.com, tony.luck@...el.com,
 pbonzini@...hat.com, vkuznets@...hat.com, seanjc@...gle.com,
 luto@...nel.org, boris.ostrovsky@...cle.com, kys@...rosoft.com,
 haiyangz@...rosoft.com, decui@...rosoft.com, dapeng1.mi@...ux.intel.com
Subject: Re: [PATCH v3 09/14] x86/xen/msr: Remove calling
 native_{read,write}_msr{,_safe}() in pmu_msr_{read,write}()

On 25.04.25 10:34, Xin Li (Intel) wrote:
> hpa found that pmu_msr_write() is actually a completely pointless
> function [1]: all it does is shuffle some arguments, then calls
> pmu_msr_chk_emulated() and if it returns true AND the emulated flag
> is clear then does *exactly the same thing* that the calling code
> would have done if pmu_msr_write() itself had returned true.  And
> pmu_msr_read() does the equivalent stupidity.
> 
> Remove the calls to native_{read,write}_msr{,_safe}() within
> pmu_msr_{read,write}().  Instead reuse the existing calling code
> that decides whether to call native_{read,write}_msr{,_safe}() based
> on the return value from pmu_msr_{read,write}().  Consequently,
> eliminate the need to pass an error pointer to pmu_msr_{read,write}().
> 
> While at it, refactor pmu_msr_write() to take the MSR value as a u64
> argument, replacing the current dual u32 arguments, because the dual
> u32 arguments were only used to call native_write_msr{,_safe}(), which
> has now been removed.
> 
> [1]: https://lore.kernel.org/lkml/0ec48b84-d158-47c6-b14c-3563fd14bcc4@zytor.com/
> 
> Suggested-by: H. Peter Anvin (Intel) <hpa@...or.com>
> Sign-off-by: Xin Li (Intel) <xin@...or.com>

Reviewed-by: Juergen Gross <jgross@...e.com>


Juergen

Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3684 bytes)

Download attachment "OpenPGP_signature.asc" of type "application/pgp-signature" (496 bytes)