x86/bugs, KVM: Support the combination of guest and host IBRS

[mirror_ubuntu-artful-kernel.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 097f3daae03707762e40b97cb71c378b82962413..7a7bd88b2e14e01c4fd127d09dfa78d329d61e37 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1082,6 +1082,13 @@ static inline bool is_machine_check(u32 intr_info)
                (INTR_TYPE_HARD_EXCEPTION | MC_VECTOR | INTR_INFO_VALID_MASK);
 }
 
+/* Undocumented: icebp/int1 */
+static inline bool is_icebp(u32 intr_info)
+{
+       return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
+               == (INTR_TYPE_PRIV_SW_EXCEPTION | INTR_INFO_VALID_MASK);
+}
+
 static inline bool cpu_has_vmx_msr_bitmap(void)
 {
        return vmcs_config.cpu_based_exec_ctrl & CPU_BASED_USE_MSR_BITMAPS;
@@ -5844,7 +5851,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
                      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {
                        vcpu->arch.dr6 &= ~15;
                        vcpu->arch.dr6 |= dr6 | DR6_RTM;
-                       if (!(dr6 & ~DR6_RESERVED)) /* icebp */
+                       if (is_icebp(intr_info))
                                skip_emulated_instruction(vcpu);
 
                        kvm_queue_exception(vcpu, DB_VECTOR);
@@ -8856,14 +8863,14 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 #endif
                        "pushf\n\t"
                        __ASM_SIZE(push) " $%c[cs]\n\t"
-                       "call *%[entry]\n\t"
+                       CALL_NOSPEC
                        :
 #ifdef CONFIG_X86_64
                        [sp]"=&r"(tmp),
 #endif
                        ASM_CALL_CONSTRAINT
                        :
-                       [entry]"r"(entry),
+                       THUNK_TARGET(entry),
                        [ss]"i"(__KERNEL_DS),
                        [cs]"i"(__KERNEL_CS)
                        );
@@ -9097,9 +9104,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
        atomic_switch_perf_msrs(vmx);
 
-       if (ibrs_inuse)
-               add_atomic_switch_msr(vmx, MSR_IA32_SPEC_CTRL,
-                       vcpu->arch.spec_ctrl, FEATURE_ENABLE_IBRS);
+       /* SMB: Ignore ibrs_inuse but rely on vcpu value */
+       x86_spec_ctrl_set_guest(vcpu->arch.spec_ctrl);
 
        debugctlmsr = get_debugctlmsr();
 
@@ -9223,6 +9229,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 #endif
              );
 
+       x86_spec_ctrl_restore_host(vcpu->arch.spec_ctrl);
+
        /* Eliminate branch target predictions from guest mode */
        vmexit_fill_RSB();