From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
KarimAllah Ahmed <karahmed@amazon.de>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Ashok Raj <ashok.raj@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Dan Williams <dan.j.williams@intel.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Greg KH <gregkh@linuxfoundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v6 2/5] KVM: x86: Add IBPB support
Date: Fri, 2 Feb 2018 20:52:58 +0000 [thread overview]
Message-ID: <20180202205258.2819b14f@alans-desktop> (raw)
In-Reply-To: <20180202202857.GI28192@char.us.oracle.com>
> > No. The AMD feature bits give us more fine-grained support for exposing
> > IBPB or IBRS alone, so we expose those bits on Intel too.
>
> But but.. that runs smack against the idea of exposing a platform that
> is as close to emulating the real hardware as possible.
Agreed, and it's asking for problems in the future if for example Intel
or another non AMD vendor did ever use that leaf for something different.
Now whether there ought to be an MSR range every vendor agrees is never
implemented so software can use it is an interesting discussion.
Alan
next prev parent reply other threads:[~2018-02-02 20:53 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-01 21:59 [PATCH v6 0/5] KVM: Expose speculation control feature to guests KarimAllah Ahmed
2018-02-01 21:59 ` [PATCH v6 1/5] KVM: x86: Update the reverse_cpuid list to include CPUID_7_EDX KarimAllah Ahmed
2018-02-02 17:37 ` Jim Mattson
2018-02-01 21:59 ` [PATCH v6 2/5] KVM: x86: Add IBPB support KarimAllah Ahmed
2018-02-02 17:49 ` Konrad Rzeszutek Wilk
2018-02-02 18:02 ` David Woodhouse
2018-02-02 19:56 ` Konrad Rzeszutek Wilk
2018-02-02 20:16 ` David Woodhouse
2018-02-02 20:28 ` Konrad Rzeszutek Wilk
2018-02-02 20:31 ` David Woodhouse
2018-02-02 20:52 ` Konrad Rzeszutek Wilk
2018-02-02 20:52 ` Alan Cox [this message]
2018-02-05 19:22 ` Paolo Bonzini
2018-02-05 19:24 ` Paolo Bonzini
2018-02-16 3:44 ` Jim Mattson
2018-02-16 4:22 ` Andi Kleen
2018-05-03 1:27 ` Wanpeng Li
2018-05-03 9:19 ` Paolo Bonzini
2018-05-03 12:01 ` Wanpeng Li
2018-05-03 12:46 ` Tian, Kevin
2018-02-01 21:59 ` [PATCH v6 3/5] KVM: VMX: Emulate MSR_IA32_ARCH_CAPABILITIES KarimAllah Ahmed
2018-02-02 10:53 ` Darren Kenny
2018-02-02 17:35 ` Jim Mattson
2018-02-02 17:51 ` Konrad Rzeszutek Wilk
2018-02-01 21:59 ` [PATCH v6 4/5] KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL KarimAllah Ahmed
2018-02-02 11:03 ` Darren Kenny
2018-02-02 11:27 ` David Woodhouse
2018-02-02 17:53 ` Konrad Rzeszutek Wilk
2018-02-02 18:05 ` David Woodhouse
2018-02-02 18:19 ` Konrad Rzeszutek Wilk
2018-02-02 17:57 ` Jim Mattson
2018-02-01 21:59 ` [PATCH v6 5/5] KVM: SVM: " KarimAllah Ahmed
2018-02-02 11:06 ` Darren Kenny
2018-02-02 18:02 ` Konrad Rzeszutek Wilk
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