From: Yang Weijiang <weijiang.yang@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Yang Weijiang <weijiang.yang@intel.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, jmattson@google.com,
yu.c.zhang@linux.intel.com, yu-cheng.yu@intel.com
Subject: Re: [PATCH v8 3/7] KVM: VMX: Pass through CET related MSRs
Date: Mon, 16 Dec 2019 10:18:16 +0800 [thread overview]
Message-ID: <20191216021816.GA10764@local-michael-cet-test> (raw)
In-Reply-To: <20191210211821.GL15758@linux.intel.com>
On Tue, Dec 10, 2019 at 01:18:21PM -0800, Sean Christopherson wrote:
> On Fri, Nov 01, 2019 at 04:52:18PM +0800, Yang Weijiang wrote:
> > CET MSRs pass through Guest directly to enhance performance.
> > CET runtime control settings are stored in MSR_IA32_{U,S}_CET,
> > Shadow Stack Pointer(SSP) are stored in MSR_IA32_PL{0,1,2,3}_SSP,
> > SSP table base address is stored in MSR_IA32_INT_SSP_TAB,
> > these MSRs are defined in kernel and re-used here.
> >
> +
> > static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
> > {
> > struct vcpu_vmx *vmx = to_vmx(vcpu);
> > @@ -7025,6 +7087,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
> > if (boot_cpu_has(X86_FEATURE_INTEL_PT) &&
> > guest_cpuid_has(vcpu, X86_FEATURE_INTEL_PT))
> > update_intel_pt_cfg(vcpu);
> > +
> > + if (!is_guest_mode(vcpu))
> > + vmx_pass_cet_msrs(vcpu);
>
> Hmm, this looks insufficent, e.g. deliberately toggling CET from on->off
> while in guest mode would put KVM in a weird state as the msr bitmap for
> L1 would still allow L1 to access the CET MSRs.
>
Hi, Sean,
I don't get you, there's guest mode check before access CET msrs, it'll
fail if it's in guest mode.
> Allowing KVM_SET_CPUID{2} while running a nested guest seems bogus, can we
> kill that path entirely with -EINVAL?
>
Do you mean don't expose CET cpuids to L2 guest?
thanks!
> > }
> >
> > static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
> > --
> > 2.17.2
> >
next prev parent reply other threads:[~2019-12-16 2:17 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 8:52 [PATCH v8 0/7] Introduce support for guest CET feature Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 1/7] KVM: CPUID: Fix IA32_XSS support in CPUID(0xd,i) enumeration Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 2/7] KVM: VMX: Define CET VMCS fields and #CP flag Yang Weijiang
2019-12-10 21:00 ` Sean Christopherson
2019-12-11 1:45 ` Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 3/7] KVM: VMX: Pass through CET related MSRs Yang Weijiang
2019-12-10 21:18 ` Sean Christopherson
2019-12-11 1:32 ` Yang Weijiang
2019-12-11 1:50 ` Sean Christopherson
2019-12-11 2:27 ` Yang Weijiang
2019-12-16 2:18 ` Yang Weijiang [this message]
2019-12-18 0:34 ` Sean Christopherson
2019-12-18 13:55 ` Yang Weijiang
2019-12-18 16:02 ` Sean Christopherson
2019-11-01 8:52 ` [PATCH v8 4/7] KVM: VMX: Load CET states on vmentry/vmexit Yang Weijiang
2019-12-10 21:23 ` Sean Christopherson
2019-12-11 1:54 ` Yang Weijiang
2019-12-11 16:35 ` Sean Christopherson
2019-12-12 1:04 ` Yang Weijiang
2019-12-18 0:30 ` Sean Christopherson
2019-12-18 13:20 ` Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 5/7] KVM: X86: Enable CET bits update in IA32_XSS Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 6/7] KVM: X86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2019-12-10 21:27 ` Sean Christopherson
2019-12-11 2:03 ` Yang Weijiang
2019-11-01 8:52 ` [PATCH v8 7/7] KVM: X86: Add user-space access interface for CET MSRs Yang Weijiang
2019-12-10 21:58 ` Sean Christopherson
2019-12-11 2:19 ` Yang Weijiang
2019-12-11 16:27 ` Sean Christopherson
2019-12-12 0:42 ` Yang Weijiang
2019-12-12 16:03 ` [PATCH v8 0/7] Introduce support for guest CET feature Konrad Rzeszutek Wilk
2019-12-13 0:44 ` Yang Weijiang
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