Re: [RFC PATCH v4 0/8] This patch-set is to enable Guest CET support

[Yang Weijiang]

On Mon, Mar 18, 2019 at 11:03:43PM +0800, Yang Weijiang wrote:
> Control-flow Enforcement Technology (CET) provides protection against
> return/jump-oriented programming (ROP) attacks. To make kvm Guest OS own
> the capability, this patch-set is required. It enables CET related CPUID
> report, xsaves/xrstors, vmx entry configuration etc. for Guest OS.
> 
> PATCH 1    : Define CET VMCS fields and bits.
> PATCH 2/3  : Report CET feature support in CPUID.
> PATCH 4    : Fix xsaves size calculation issue.
> PATCH 5    : Pass through CET MSRs to Guest.
> PATCH 6    : Set Guest CET state auto loading bit.
> PATCH 7    : Load Guest fpu state when accessing CET XSAVES managed MSRs.
> PATCH 8    : Add CET MSR user space access interface.
> 
> Changelog:
> 
>  v4:
>  - Add Sean's patch for loading Guest fpu state before access XSAVES
>    managed CET MSRs.
>  - Melt down CET bits setting into CPUID configuration patch.
>  - Add VMX interface to query Host XSS.
>  - Check Host and Guest XSS support bits before set Guest XSS.
>  - Make Guest SHSTK and IBT feature enabling independent.
>  - Do not report CET support to Guest when Host CET feature is
>    Disabled.
> 
>  v3:
>  - Modified patches to make Guest CET independent to Host enabling.
>  - Added patch 8 to add user space access for Guest CET MSR access.
>  - Modified code comments and patch description to reflect changes.
> 
>  v2:
>  - Re-ordered patch sequence, combined one patch.
>  - Added more description for CET related VMCS fields.
>  - Added Host CET capability check while enabling Guest CET loading bit.
>  - Added Host CET capability check while reporting Guest CPUID(EAX=7,
>    EXC=0).
>  - Modified code in reporting Guest CPUID(EAX=D,ECX>=1), make it clearer.
>  - Added Host and Guest XSS mask check while setting bits for Guest XSS.
> 
> 
> Sean Christopherson (1):
>   KVM:x86: load guest fpu state when accessing MSRs managed by XSAVES
> 
> Yang Weijiang (7):
>   KVM:VMX: Define CET VMCS fields and bits
>   KVM:CPUID: Add CET CPUID support for Guest
>   KVM:CPUID: Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1).
>   KVM:VMX: Pass through host CET related MSRs to Guest.
>   KVM:VMX: Load Guest CET via VMCS when CET is enabled in Guest
>   KVM:x86: Allow Guest to set supported bits in XSS
>   KVM:x86: Add user-space read/write interface for CET MSRs
> 
>  arch/x86/include/asm/kvm_host.h  |  5 +-
>  arch/x86/include/asm/msr-index.h |  2 +
>  arch/x86/include/asm/vmx.h       |  8 +++
>  arch/x86/kvm/cpuid.c             | 53 ++++++++++++++------
>  arch/x86/kvm/vmx.c               | 86 ++++++++++++++++++++++++++++++--
>  arch/x86/kvm/x86.c               | 32 +++++++++++-
>  arch/x86/kvm/x86.h               |  4 ++
>  7 files changed, 167 insertions(+), 23 deletions(-)
> 
> -- 
> 2.17.1
Hi, Paolo and Sean,
Do you have any comments on v4 patches?