From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Yang Weijiang <weijiang.yang@intel.com>
Cc: pbonzini@redhat.com, kvm@vger.kernel.org, mst@redhat.com,
rkrcmar@redhat.com, jmattson@google.com,
linux-kernel@vger.kernel.org, yu-cheng.yu@intel.com,
Zhang Yi Z <yi.z.zhang@linux.intel.com>
Subject: Re: [RFC PATCH v4 4/8] KVM:VMX: Pass through host CET related MSRs to Guest.
Date: Tue, 2 Apr 2019 13:27:33 -0700 [thread overview]
Message-ID: <20190402202733.GI31303@linux.intel.com> (raw)
In-Reply-To: <20190318150351.15550-5-weijiang.yang@intel.com>
On Mon, Mar 18, 2019 at 11:03:47PM +0800, Yang Weijiang wrote:
> The CET runtime settings, i.e., CET state control bits(IA32_U_CET/
> IA32_S_CET), CET SSP(IA32_PL3_SSP/IA32_PL0_SSP) and SSP table address
> (IA32_INTERRUPT_SSP_TABLE_ADDR) are task/thread specific, therefore,
> OS needs to save/restore the states properly during context switch,
> e.g., task/thread switching, interrupt/exception handling, it uses
> xsaves/xrstors to achieve that.
>
> The difference between VMCS CET area fields and xsave CET area, is that
> the former is for state retention during Guest/Host context
> switch while the latter is for state retention during OS execution.
>
> Linux currently doesn't support CPL1 and CPL2, so SSPs for these level
> are skipped here.
>
> Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
> arch/x86/kvm/vmx.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 53cef5a3db96..28b8ac027bd7 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -11774,6 +11774,7 @@ static void nested_vmx_entry_exit_ctls_update(struct kvm_vcpu *vcpu)
> static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
> {
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> + unsigned long *msr_bitmap;
>
> if (cpu_has_secondary_exec_ctrls()) {
> vmx_compute_secondary_exec_control(vmx);
> @@ -11791,6 +11792,18 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
> nested_vmx_cr_fixed1_bits_update(vcpu);
> nested_vmx_entry_exit_ctls_update(vcpu);
> }
> +
> + msr_bitmap = vmx->vmcs01.msr_bitmap;
> +
> + if (guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) ||
> + guest_cpuid_has(vcpu, X86_FEATURE_IBT)) {
> + vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_U_CET, MSR_TYPE_RW);
> + vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_S_CET, MSR_TYPE_RW);
> + vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_INT_SSP_TAB, MSR_TYPE_RW);
> + vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_PL0_SSP, MSR_TYPE_RW);
I thought we had agreed to pass-through PL1 and PL2, or am I misremembering?
> + vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_PL3_SSP, MSR_TYPE_RW);
> + }
> +
> }
>
> static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-04-02 20:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 15:03 [RFC PATCH v4 0/8] This patch-set is to enable Guest CET support Yang Weijiang
2019-03-18 15:03 ` [RFC PATCH v4 1/8] KVM:VMX: Define CET VMCS fields and bits Yang Weijiang
2019-04-02 19:57 ` Sean Christopherson
2019-03-18 15:03 ` [RFC PATCH v4 2/8] KVM:CPUID: Add CET CPUID support for Guest Yang Weijiang
2019-04-02 20:21 ` Sean Christopherson
2019-04-02 20:40 ` Sean Christopherson
2019-03-18 15:03 ` [RFC PATCH v4 3/8] KVM:CPUID: Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1) Yang Weijiang
2019-04-02 20:27 ` Sean Christopherson
2019-03-18 15:03 ` [RFC PATCH v4 4/8] KVM:VMX: Pass through host CET related MSRs to Guest Yang Weijiang
2019-04-02 20:27 ` Sean Christopherson [this message]
2019-04-02 20:46 ` Yang Weijiang
2019-03-18 15:03 ` [RFC PATCH v4 5/8] KVM:VMX: Load Guest CET via VMCS when CET is enabled in Guest Yang Weijiang
2019-04-02 20:30 ` Sean Christopherson
2019-03-18 15:03 ` [RFC PATCH v4 6/8] KVM:x86: Allow Guest to set supported bits in XSS Yang Weijiang
2019-03-18 15:03 ` [RFC PATCH v4 7/8] KVM:x86: load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2019-04-02 20:39 ` Sean Christopherson
2019-03-18 15:03 ` [RFC PATCH v4 8/8] KVM:x86: Add user-space read/write interface for CET MSRs Yang Weijiang
2019-04-02 20:35 ` Sean Christopherson
2019-03-25 20:45 ` [RFC PATCH v4 0/8] This patch-set is to enable Guest CET support Yang Weijiang
2019-03-26 22:31 ` Sean Christopherson
2019-04-02 20:10 ` Sean Christopherson
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