All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sean Christopherson <seanjc@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org, Reiji Watanabe <reijiw@google.com>,
	Jim Mattson <jmattson@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Sean Christopherson <seanjc@google.com>
Subject: [PATCH 0/2] x86/cpu: RDPID+MSR_TSC_AUX fix and a cleanup
Date: Tue,  4 May 2021 15:56:30 -0700	[thread overview]
Message-ID: <20210504225632.1532621-1-seanjc@google.com> (raw)

Fix a bug where MSR_TSC_AUX is left uninitialized in the theoretically
possible scenario where RDPID is supported by RDTSCP is not.  AFAIK, no
such CPUs exits, but both Intel and AMD architecturally allow RDPID and
MSR_TSC_AUX to exist without RDTSCP.

Found by inspection when cleaning up a similar mess in KVM.  Confirmed
the bug and verified the fix by running the problematic CPU model under
KVM (once KVM's even bigger trainwreck was fixed).

Sean Christopherson (2):
  x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported
  x86/cpu: Remove write_tsc() and write_rdtscp_aux() wrappers

 arch/x86/include/asm/msr.h   | 4 ----
 arch/x86/kernel/cpu/common.c | 4 ++--
 2 files changed, 2 insertions(+), 6 deletions(-)

-- 
2.31.1.527.g47e6f16901-goog


             reply	other threads:[~2021-05-04 22:56 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-04 22:56 Sean Christopherson [this message]
2021-05-04 22:56 ` [PATCH 1/2] x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported Sean Christopherson
2021-05-06 12:14   ` [tip: x86/urgent] " tip-bot2 for Sean Christopherson
2021-05-04 22:56 ` [PATCH 2/2] x86/cpu: Remove write_tsc() and write_rdtscp_aux() wrappers Sean Christopherson
2021-05-06 12:14   ` [tip: x86/urgent] " tip-bot2 for Sean Christopherson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210504225632.1532621-1-seanjc@google.com \
    --to=seanjc@google.com \
    --cc=bp@alien8.de \
    --cc=hpa@zytor.com \
    --cc=jmattson@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=reijiw@google.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.