From: Yang Weijiang <weijiang.yang@intel.com>
To: Jim Mattson <jmattson@google.com>
Cc: "Yang Weijiang" <weijiang.yang@intel.com>,
"kvm list" <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Sean Christopherson" <sean.j.christopherson@intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Aaron Lewis" <aaronlewis@google.com>
Subject: Re: [PATCH v7 2/7] kvm: vmx: Define CET VMCS fields and CPUID flags
Date: Wed, 9 Oct 2019 13:56:46 +0800 [thread overview]
Message-ID: <20191009055646.GA27851@local-michael-cet-test> (raw)
In-Reply-To: <CALMp9eT8uBo0+1x1x=mZ48XqYsR_3MTShZMNEaZWEKjt7i1Sqg@mail.gmail.com>
On Wed, Oct 02, 2019 at 11:04:07AM -0700, Jim Mattson wrote:
> On Thu, Sep 26, 2019 at 7:17 PM Yang Weijiang <weijiang.yang@intel.com> wrote:
> >
> > CET(Control-flow Enforcement Technology) is an upcoming Intel(R)
> > processor feature that blocks Return/Jump-Oriented Programming(ROP)
> > attacks. It provides the following capabilities to defend
> > against ROP/JOP style control-flow subversion attacks:
> > /*
> > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> > index 9d282fec0a62..1aa86b87b6ab 100644
> > --- a/arch/x86/kvm/cpuid.c
> > +++ b/arch/x86/kvm/cpuid.c
> > @@ -365,13 +365,13 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
> > F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
> > F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
> > F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
> > - F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B);
> > + F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | F(SHSTK);
> >
> > /* cpuid 7.0.edx*/
> > const u32 kvm_cpuid_7_0_edx_x86_features =
> > F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
> > F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
> > - F(MD_CLEAR);
> > + F(MD_CLEAR) | F(IBT);
>
> Claiming that SHSTK and IBT are supported in the guest seems premature
> as of this change, since you haven't actually done anything to
> virtualize the features yet.
>
OK, will put the flags in other patch.
> > /* cpuid 7.1.eax */
> > const u32 kvm_cpuid_7_1_eax_x86_features =
> > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> > index fbffabad0370..a85800b23e6e 100644
> > --- a/arch/x86/kvm/x86.h
> > +++ b/arch/x86/kvm/x86.h
> > @@ -298,7 +298,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
> > * Right now, no XSS states are used on x86 platform,
> > * expand the macro for new features.
> > */
> > -#define KVM_SUPPORTED_XSS (0)
> > +#define KVM_SUPPORTED_XSS (XFEATURE_MASK_CET_USER \
> > + | XFEATURE_MASK_CET_KERNEL)
>
> If IA32_XSS can dynamically change within the guest, it will have to
> be enumerated by KVM_GET_MSR_INDEX_LIST.
thanks for pointing it out, need to add IA32_XSS to msrs_to_save list.
>(Note that Aaron Lewis is
> working on a series which will include that enumeration, if you'd like
> to wait.) I'm also not convinced that there is sufficient
> virtualization of these features to allow these bits to be set in the
> guest IA32_XSS at this point.
>
It's true CET is working in guest after I added XSS/XSAVES support in
KVM and QEMU, but I'd like to look at Aaron's new patch...
> > extern u64 host_xcr0;
> >
> > --
> > 2.17.2
> >
next prev parent reply other threads:[~2019-10-09 5:55 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 2:19 [PATCH v7 0/7] Introduce support for Guest CET feature Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 1/7] KVM: CPUID: Fix IA32_XSS support in CPUID(0xd,i) enumeration Yang Weijiang
2019-10-02 17:26 ` Jim Mattson
2019-10-08 8:30 ` Yang Weijiang
2019-10-17 19:46 ` Sean Christopherson
2019-10-18 1:28 ` Yang Weijiang
2019-10-22 19:46 ` Sean Christopherson
2019-10-23 1:16 ` Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 2/7] kvm: vmx: Define CET VMCS fields and CPUID flags Yang Weijiang
2019-10-02 18:04 ` Jim Mattson
2019-10-09 5:56 ` Yang Weijiang [this message]
2019-09-27 2:19 ` [PATCH v7 3/7] KVM: VMX: Pass through CET related MSRs to Guest Yang Weijiang
2019-10-02 18:18 ` Jim Mattson
2019-10-09 6:15 ` Yang Weijiang
2019-10-10 19:04 ` Jim Mattson
2019-10-11 1:51 ` Yang Weijiang
2019-10-17 20:04 ` Sean Christopherson
2019-10-18 1:31 ` Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 4/7] KVM: VMX: Load Guest CET via VMCS when CET is enabled in Guest Yang Weijiang
2019-10-02 18:54 ` Jim Mattson
2019-10-09 6:43 ` Yang Weijiang
2019-10-09 23:08 ` Jim Mattson
2019-10-10 1:30 ` Yang Weijiang
2019-10-10 23:44 ` Jim Mattson
2019-10-11 1:43 ` Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 5/7] kvm: x86: Add CET CR4 bit and XSS support Yang Weijiang
2019-10-02 19:05 ` Jim Mattson
2019-10-17 19:56 ` Sean Christopherson
2019-10-18 1:58 ` Yang Weijiang
2019-10-22 20:13 ` Sean Christopherson
2019-10-23 1:19 ` Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 6/7] KVM: x86: Load Guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2019-10-02 19:56 ` Jim Mattson
2019-10-09 6:46 ` Yang Weijiang
2019-09-27 2:19 ` [PATCH v7 7/7] KVM: x86: Add user-space access interface for CET MSRs Yang Weijiang
2019-10-02 20:57 ` Jim Mattson
2019-10-09 6:56 ` Yang Weijiang
2019-10-17 19:58 ` Sean Christopherson
2019-10-18 1:32 ` Yang Weijiang
2019-10-02 22:40 ` [PATCH v7 0/7] Introduce support for Guest CET feature Jim Mattson
2019-10-03 13:01 ` Yang Weijiang
2019-10-03 16:33 ` Jim Mattson
2019-10-08 8:50 ` Yang Weijiang
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