From: Paolo Bonzini <pbonzini@redhat.com>
To: Xiaoyao Li <xiaoyao.li@linux.intel.com>, Kyle Huey <me@kylehuey.com>
Cc: "Kyle Huey" <khuey@kylehuey.com>, "Chao Gao" <chao.gao@intel.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, "kvm list" <kvm@vger.kernel.org>,
"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kvm/x86/vmx: switch MSR_MISC_FEATURES_ENABLES between host and guest
Date: Thu, 14 Mar 2019 12:30:54 +0100 [thread overview]
Message-ID: <7629bbe3-03d0-8f78-28b5-ac4eb34d24c4@redhat.com> (raw)
In-Reply-To: <059a5c6309b0e43695e5532e698d07750502d6d3.camel@linux.intel.com>
On 14/03/19 11:43, Xiaoyao Li wrote:
> Yes, you are right. With your patches, only when we enable cpuid faulting for
> the QEMU or other VMM userspace processes via arch_prctl, does it "leak" into
> the KVM guest.
>
> But arch_prctl is not the only way to enable it. We can enable cpuid faulting
> via module "msr.ko". And I think it's indeed an issue, we should not ignore it
> as it needs special cases and purpose to make it happen so far.
Whatever is done with "msr.ko" is a non-issue. msr.ko is at best a
debugging tool if you use it for MSRs that the kernel can write. That
said, even the arch_prctl is an issue, as well as Peter's patch you
quote below.
The patch is a good idea even though it should be implemented in a more
efficient way.
Paolo
> Besides, Peter's this patch https://patchwork.kernel.org/patch/10850143/ is much
> likely to cause the cpuid fauting enabled in host by default during kernel
> startup. If that one is going to be applied, it's better to fix the cpuid
> faulting leak issue before that.
next prev parent reply other threads:[~2019-03-14 11:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 6:38 Xiaoyao Li
2019-03-14 7:06 ` Xiaoyao Li
2019-03-14 8:43 ` Kyle Huey
2019-03-14 10:43 ` Xiaoyao Li
2019-03-14 11:30 ` Paolo Bonzini [this message]
2019-03-14 11:28 ` Paolo Bonzini
2019-03-14 12:10 ` Xiaoyao Li
2019-03-14 12:37 ` Xiaoyao Li
2019-03-14 14:44 ` Paolo Bonzini
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