From: Andy Lutomirski <luto@kernel.org>
To: Jim Mattson <jmattson@google.com>
Cc: "Andy Lutomirski" <luto@kernel.org>,
"Kyle Huey" <me@kylehuey.com>,
"Robert O'Callahan" <robert@ocallahan.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, "X86 ML" <x86@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Jeff Dike" <jdike@addtoit.com>,
"Richard Weinberger" <richard@nod.at>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Shuah Khan" <shuah@kernel.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Borislav Petkov" <bp@suse.de>,
"Peter Zijlstra" <peterz@infradead.org>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Len Brown" <len.brown@intel.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
"Dmitry Safonov" <dsafonov@virtuozzo.com>,
"David Matlack" <dmatlack@google.com>,
"Nadav Amit" <nadav.amit@gmail.com>,
"Andi Kleen" <andi@firstfloor.org>,
LKML <linux-kernel@vger.kernel.org>,
user-mode-linux-devel@lists.sourceforge.net,
"open list:USER-MODE LINUX (UML)"
<user-mode-linux-user@lists.sourceforge.net>,
"Linux FS Devel" <linux-fsdevel@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
"kvm list" <kvm@vger.kernel.org>
Subject: Re: [PATCH v14 8/9] KVM: x86: virtualize cpuid faulting
Date: Fri, 27 Jul 2018 15:58:13 -0700 [thread overview]
Message-ID: <CALCETrUCiptFxdvAEZFo7A52eEmAEk12bJKTkX8jNLBA_391wg@mail.gmail.com> (raw)
In-Reply-To: <CALMp9eQ3VOOdQpZ2=rqB1W3=RnyZXDxrqXgADsDZ0eSH_8r9tQ@mail.gmail.com>
On Fri, Jul 27, 2018 at 2:30 PM, Jim Mattson <jmattson@google.com> wrote:
> On Fri, Jul 27, 2018 at 2:05 PM, Andy Lutomirski <luto@kernel.org> wrote:
>> Does KVM *have* a concept of "maximum non-turbo frequency" of the
>> guest that it would make sense to expose here? If so, presumably the
>> right solution is to expose it.
>
> KVM has the concept of a guest's invariant TSC frequency. The Maximum
> Non-Turbo Ratio is just some fraction of that. Sadly, the fraction is
> 100 MHz, 133.33MHz, or the "scalable bus frequency" from some other
> MSR, depending on microarchitecture.
Which is problematic, unless KVM wants to start deciding what the base
clock is. There's MSR_FSB_FREQ, which is supported on Atom only,
IIRC.
I really wish Intel would get its act together.
next prev parent reply other threads:[~2018-07-27 22:58 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-08 8:09 [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
2017-02-08 8:09 ` [PATCH v14 1/9] x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl Kyle Huey
2017-02-08 8:09 ` [PATCH v14 2/9] x86/arch_prctl/64: Rename do_arch_prctl to do_arch_prctl_64 Kyle Huey
2017-02-08 8:09 ` [PATCH v14 3/9] x86/arch_prctl: Add do_arch_prctl_common Kyle Huey
2017-02-08 8:09 ` [PATCH v14 4/9] x86/syscalls/32: Wire up arch_prctl on x86-32 Kyle Huey
2017-02-08 8:09 ` [PATCH v14 5/9] x86/cpufeature: Detect CPUID faulting support Kyle Huey
2017-02-08 8:09 ` [PATCH v14 6/9] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey
2017-02-08 8:09 ` [PATCH v14 7/9] x86/arch_prctl: Selftest for ARCH_[GET|SET]_CPUID Kyle Huey
2017-02-08 8:09 ` [PATCH v14 8/9] KVM: x86: virtualize cpuid faulting Kyle Huey
2018-07-27 17:15 ` Jim Mattson
2018-07-27 19:41 ` Andy Lutomirski
2018-07-27 20:28 ` Jim Mattson
2018-07-27 20:46 ` Andy Lutomirski
2018-07-27 21:03 ` Jim Mattson
2018-07-27 21:05 ` Andy Lutomirski
2018-07-27 21:30 ` Jim Mattson
2018-07-27 22:58 ` Andy Lutomirski [this message]
2017-02-08 8:09 ` [PATCH v14 9/9] x86/arch_prctl: Rename 'code' argument to 'option' Kyle Huey
2017-02-10 13:07 ` [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Thomas Gleixner
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