From: Yang Weijiang <weijiang.yang@intel.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, sean.j.christopherson@intel.com,
jmattson@google.com
Cc: yu.c.zhang@linux.intel.com, Yang Weijiang <weijiang.yang@intel.com>
Subject: [RESEND v13 03/11] KVM: VMX: Set guest CET MSRs per KVM and host configuration
Date: Thu, 16 Jul 2020 11:16:19 +0800 [thread overview]
Message-ID: <20200716031627.11492-4-weijiang.yang@intel.com> (raw)
In-Reply-To: <20200716031627.11492-1-weijiang.yang@intel.com>
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.
MSR_IA32_U_CET and MSR_IA32_PL3_SSP are used for user-mode protection,the MSR
contents are switched between threads during scheduling, it makes sense to pass
through them so that the guest kernel can use xsaves/xrstors to operate them
efficiently. Other MSRs are used for non-user mode protection. See SDM for detailed
info.
The difference between CET VMCS fields and CET MSRs is that,the former are used
during VMEnter/VMExit, whereas the latter are used for CET state storage between
task/thread scheduling.
Co-developed-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
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/vmx.c | 46 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 3 +++
2 files changed, 49 insertions(+)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 13745f2a5ecd..a9f135c52cbc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3126,6 +3126,13 @@ void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd)
vmcs_writel(GUEST_CR3, guest_cr3);
}
+static bool is_cet_state_supported(struct kvm_vcpu *vcpu, u32 xss_states)
+{
+ return ((supported_xss & xss_states) &&
+ (guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) ||
+ guest_cpuid_has(vcpu, X86_FEATURE_IBT)));
+}
+
int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -7230,6 +7237,42 @@ static void update_intel_pt_cfg(struct kvm_vcpu *vcpu)
vmx->pt_desc.ctl_bitmask &= ~(0xfULL << (32 + i * 4));
}
+static void vmx_update_intercept_for_cet_msr(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
+ bool incpt;
+
+ incpt = !is_cet_state_supported(vcpu, XFEATURE_MASK_CET_USER);
+ /*
+ * U_CET is required for USER CET, and U_CET, PL3_SPP are bound as
+ * one component and controlled by IA32_XSS[bit 11].
+ */
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_U_CET, MSR_TYPE_RW,
+ incpt);
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PL3_SSP, MSR_TYPE_RW,
+ incpt);
+
+ incpt = !is_cet_state_supported(vcpu, XFEATURE_MASK_CET_KERNEL);
+ /*
+ * S_CET is required for KERNEL CET, and PL0_SSP ... PL2_SSP are
+ * bound as one component and controlled by IA32_XSS[bit 12].
+ */
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_S_CET, MSR_TYPE_RW,
+ incpt);
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PL0_SSP, MSR_TYPE_RW,
+ incpt);
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PL1_SSP, MSR_TYPE_RW,
+ incpt);
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_PL2_SSP, MSR_TYPE_RW,
+ incpt);
+
+ incpt |= !guest_cpuid_has(vcpu, X86_FEATURE_SHSTK);
+ /* SSP_TAB is only available for KERNEL SHSTK.*/
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_INT_SSP_TAB, MSR_TYPE_RW,
+ incpt);
+}
+
static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -7268,6 +7311,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
vmx_set_guest_msr(vmx, msr, enabled ? 0 : TSX_CTRL_RTM_DISABLE);
}
}
+
+ if (supported_xss & (XFEATURE_MASK_CET_KERNEL | XFEATURE_MASK_CET_USER))
+ vmx_update_intercept_for_cet_msr(vcpu);
}
static __init void vmx_set_cpu_caps(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 88c593f83b28..ea8a9dc9fbad 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -184,6 +184,9 @@ static struct kvm_shared_msrs __percpu *shared_msrs;
| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
| XFEATURE_MASK_PKRU)
+#define KVM_SUPPORTED_XSS (XFEATURE_MASK_CET_USER | \
+ XFEATURE_MASK_CET_KERNEL)
+
u64 __read_mostly host_efer;
EXPORT_SYMBOL_GPL(host_efer);
--
2.17.2
next prev parent reply other threads:[~2020-07-16 3:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 3:16 [RESEND PATCH v13 00/11] Introduce support for guest CET feature Yang Weijiang
2020-07-16 3:16 ` [RESEND v13 01/11] KVM: x86: Include CET definitions for KVM test purpose Yang Weijiang
2020-07-16 3:16 ` [RESEND v13 02/11] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2020-07-22 19:48 ` Sean Christopherson
2020-07-16 3:16 ` Yang Weijiang [this message]
2020-07-22 20:14 ` [RESEND v13 03/11] KVM: VMX: Set guest CET MSRs per KVM and host configuration Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 04/11] KVM: VMX: Configure CET settings upon guest CR0/4 changing Yang Weijiang
2020-07-22 20:31 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 05/11] KVM: x86: Refresh CPUID once guest changes XSS bits Yang Weijiang
2020-07-22 20:32 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 06/11] KVM: x86: Load guest fpu state when access MSRs managed by XSAVES Yang Weijiang
2020-07-22 20:32 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 07/11] KVM: x86: Add userspace access interface for CET MSRs Yang Weijiang
2020-07-22 20:54 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 08/11] KVM: VMX: Enable CET support for nested VM Yang Weijiang
2020-07-22 21:20 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 09/11] KVM: VMX: Add VMCS dump and sanity check for CET states Yang Weijiang
2020-07-22 21:29 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 10/11] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2020-07-22 21:29 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 11/11] KVM: x86: Enable CET virtualization and advertise CET to userspace Yang Weijiang
2020-07-22 21:33 ` Sean Christopherson
2020-07-22 19:48 ` [RESEND PATCH v13 00/11] Introduce support for guest CET feature Sean Christopherson
2020-07-23 3:17 ` Yang Weijiang
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