[PATCH 18/19] KVM: nVMX: Enable CET support for nested VMX

From: Yang Weijiang <weijiang.yang@intel.com>
To: pbonzini@redhat.com, seanjc@google.com, x86@kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	rick.p.edgecombe@intel.com
Cc: weijiang.yang@intel.com,
	Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [PATCH 18/19] KVM: nVMX: Enable CET support for nested VMX
Date: Thu, 16 Jun 2022 04:46:42 -0400	[thread overview]
Message-ID: <20220616084643.19564-19-weijiang.yang@intel.com> (raw)
In-Reply-To: <20220616084643.19564-1-weijiang.yang@intel.com>

Add vmcs12 fields for all CET fields, pass-through CET MSRs to L2 when
possible, and enumerate the VMCS controls and CR4 bit as supported.

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 14 ++++++++++++--
 arch/x86/kvm/vmx/vmcs12.c |  6 ++++++
 arch/x86/kvm/vmx/vmcs12.h | 14 +++++++++++++-
 arch/x86/kvm/vmx/vmx.c    |  2 ++
 4 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 01fe23c6fa49..f31f3d394507 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -684,6 +684,13 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
 					 MSR_IA32_PRED_CMD, MSR_TYPE_W);
 
+	/* Pass CET MSRs to nested VM if L0 and L1 are set to pass-through. */
+	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
+					 MSR_IA32_U_CET, MSR_TYPE_RW);
+
+	nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
+					 MSR_IA32_PL3_SSP, MSR_TYPE_RW);
+
 	kvm_vcpu_unmap(vcpu, &vmx->nested.msr_bitmap_map, false);
 
 	vmx->nested.force_msr_bitmap_recalc = false;
@@ -6593,7 +6600,9 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
 		VM_EXIT_HOST_ADDR_SPACE_SIZE |
 #endif
 		VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT |
-		VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
+		VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL |
+		VM_EXIT_LOAD_CET_STATE;
+
 	msrs->exit_ctls_high |=
 		VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
 		VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER |
@@ -6613,7 +6622,8 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
 		VM_ENTRY_IA32E_MODE |
 #endif
 		VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_BNDCFGS |
-		VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
+		VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL | VM_ENTRY_LOAD_CET_STATE;
+
 	msrs->entry_ctls_high |=
 		(VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR | VM_ENTRY_LOAD_IA32_EFER);
 
diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c
index 2251b60920f8..4c3836db548e 100644
--- a/arch/x86/kvm/vmx/vmcs12.c
+++ b/arch/x86/kvm/vmx/vmcs12.c
@@ -138,6 +138,9 @@ const unsigned short vmcs12_field_offsets[] = {
 	FIELD(GUEST_PENDING_DBG_EXCEPTIONS, guest_pending_dbg_exceptions),
 	FIELD(GUEST_SYSENTER_ESP, guest_sysenter_esp),
 	FIELD(GUEST_SYSENTER_EIP, guest_sysenter_eip),
+	FIELD(GUEST_S_CET, guest_s_cet),
+	FIELD(GUEST_SSP, guest_ssp),
+	FIELD(GUEST_INTR_SSP_TABLE, guest_ssp_tbl),
 	FIELD(HOST_CR0, host_cr0),
 	FIELD(HOST_CR3, host_cr3),
 	FIELD(HOST_CR4, host_cr4),
@@ -150,5 +153,8 @@ const unsigned short vmcs12_field_offsets[] = {
 	FIELD(HOST_IA32_SYSENTER_EIP, host_ia32_sysenter_eip),
 	FIELD(HOST_RSP, host_rsp),
 	FIELD(HOST_RIP, host_rip),
+	FIELD(HOST_S_CET, host_s_cet),
+	FIELD(HOST_SSP, host_ssp),
+	FIELD(HOST_INTR_SSP_TABLE, host_ssp_tbl),
 };
 const unsigned int nr_vmcs12_fields = ARRAY_SIZE(vmcs12_field_offsets);
diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
index 746129ddd5ae..672abd1f500b 100644
--- a/arch/x86/kvm/vmx/vmcs12.h
+++ b/arch/x86/kvm/vmx/vmcs12.h
@@ -117,7 +117,13 @@ struct __packed vmcs12 {
 	natural_width host_ia32_sysenter_eip;
 	natural_width host_rsp;
 	natural_width host_rip;
-	natural_width paddingl[8]; /* room for future expansion */
+	natural_width host_s_cet;
+	natural_width host_ssp;
+	natural_width host_ssp_tbl;
+	natural_width guest_s_cet;
+	natural_width guest_ssp;
+	natural_width guest_ssp_tbl;
+	natural_width paddingl[2]; /* room for future expansion */
 	u32 pin_based_vm_exec_control;
 	u32 cpu_based_vm_exec_control;
 	u32 exception_bitmap;
@@ -293,6 +299,12 @@ static inline void vmx_check_vmcs12_offsets(void)
 	CHECK_OFFSET(host_ia32_sysenter_eip, 656);
 	CHECK_OFFSET(host_rsp, 664);
 	CHECK_OFFSET(host_rip, 672);
+	CHECK_OFFSET(host_s_cet, 680);
+	CHECK_OFFSET(host_ssp, 688);
+	CHECK_OFFSET(host_ssp_tbl, 696);
+	CHECK_OFFSET(guest_s_cet, 704);
+	CHECK_OFFSET(guest_ssp, 712);
+	CHECK_OFFSET(guest_ssp_tbl, 720);
 	CHECK_OFFSET(pin_based_vm_exec_control, 744);
 	CHECK_OFFSET(cpu_based_vm_exec_control, 748);
 	CHECK_OFFSET(exception_bitmap, 752);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9aebd67ff03e..00782d1750a5 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7508,6 +7508,8 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
 	cr4_fixed1_update(X86_CR4_PKE,        ecx, feature_bit(PKU));
 	cr4_fixed1_update(X86_CR4_UMIP,       ecx, feature_bit(UMIP));
 	cr4_fixed1_update(X86_CR4_LA57,       ecx, feature_bit(LA57));
+	cr4_fixed1_update(X86_CR4_CET,	      ecx, feature_bit(SHSTK));
+	cr4_fixed1_update(X86_CR4_CET,	      edx, feature_bit(IBT));
 
 #undef cr4_fixed1_update
 }
-- 
2.27.0

