[PATCH v14 13/13] KVM: nVMX: Enable CET support for nested VMX

Yang Weijiang
2020-11-06T01:06:51Z

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 | 30 ++++++++++++++++++++++++++++--
arch/x86/kvm/vmx/vmcs12.c | 6 ++++++
arch/x86/kvm/vmx/vmcs12.h | 14 +++++++++++++-
arch/x86/kvm/vmx/vmx.c | 1 +
4 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 8abc7bdd94f7..0fe18986c259 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -638,6 +638,29 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
nested_vmx_disable_intercept_for_msr(msr_bitmap_l1, msr_bitmap_l0,
MSR_KERNEL_GS_BASE, MSR_TYPE_RW);

+ /* Pass CET MSRs to nested VM if L0 and L1 are set to pass-through. */
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_U_CET,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_PL3_SSP,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_S_CET,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_PL0_SSP,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_PL1_SSP,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_PL2_SSP,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+ nested_vmx_cond_disable_intercept_for_msr(vcpu, MSR_IA32_INT_SSP_TAB,
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_TYPE_RW);
+
/*
* Checking the L0->L1 bitmap is trying to verify two things:
*
@@ -6336,7 +6359,9 @@ 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 |
@@ -6356,7 +6381,8 @@ 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 c8e51c004f78..8fd8e0beecef 100644
--- a/arch/x86/kvm/vmx/vmcs12.c
+++ b/arch/x86/kvm/vmx/vmcs12.c
@@ -137,6 +137,9 @@ const unsigned short vmcs_field_to_offset_table[] = {
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),
@@ -149,5 +152,8 @@ const unsigned short vmcs_field_to_offset_table[] = {
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(vmcs_field_to_offset_table);
diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
index 80232daf00ff..016896c9e701 100644
--- a/arch/x86/kvm/vmx/vmcs12.h
+++ b/arch/x86/kvm/vmx/vmcs12.h
@@ -115,7 +115,13 @@ 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;
@@ -295,6 +301,12 @@ 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 6ba2027a3d44..5a3e2ff4d7ad 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7276,6 +7276,7 @@ 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));

#undef cr4_fixed1_update
}
--
2.17.2