linux-kernel - [PATCH v4 0/2] Switch MSR_MISC_FEATURES

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-next>] [day] [month] [year] [list]

Message-Id: <20190329135422.15046-1-xiaoyao.li@linux.intel.com>
Date:   Fri, 29 Mar 2019 21:54:20 +0800
From:   Xiaoyao Li <xiaoyao.li@...ux.intel.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Xiaoyao Li <xiaoyao.li@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        chao.gao@...el.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH v4 0/2] Switch MSR_MISC_FEATURES_ENABLES and one optimization

Patch 1 switches MSR_MISC_FEATURES_ENABLE between host and guest during
vcpu_{load,put} to avoid cpuid faulting and ring3mwait of host leaking
to guest. Because cpuid faulting eanbled in host may potentially cause guest
boot failure, and kvm doesn't expose ring3mwait to guest yet. 
Both two features shouldn't be leaked to guest.

Patch 2 optimizes the switch of MSR_MISC_FEATURES_ENABLES by avoiding WRMSR
whenever possible to save cycles.

==changelog==
v3->v4:
remove the helper function, and some code refine. per Sean Christopherson's
comments.

v2->v3:
- use msr_misc_features_shadow instead of reading hardware msr, from Sean
Christopherson
- avoid WRMSR whenever possible, from Sean Christopherson.

v1->v2: 
- move the save/restore of cpuid faulting bit to
vmx_prepare_swich_to_guest/vmx_prepare_swich_to_host to avoid every
vmentry RDMSR, based on Paolo's comment.

Xiaoyao Li (2):
  kvm/vmx: Switch MSR_MISC_FEATURES_ENABLES between host and guest
  x86/vmx: optimize MSR_MISC_FEATURES_ENABLES switch

 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kernel/process.c       |  1 +
 arch/x86/kvm/vmx/vmx.c          | 17 +++++++++++++++++
 arch/x86/kvm/x86.c              | 11 ++++++++---
 4 files changed, 28 insertions(+), 3 deletions(-)

-- 
2.19.1