KVM: x86: Push potential exception error code on task switches

When a fault triggers a task switch, the error code, if existent, has to
be pushed on the new task's stack. Implement the missing bits.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fb4a8869bb99..1b38d8a88cf7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3271,6 +3271,8 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
         unsigned long exit_qualification;
+        bool has_error_code = false;
+        u32 error_code = 0;
         u16 tss_selector;
         int reason, type, idt_v;
 
@@ -3293,6 +3295,13 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
                         kvm_clear_interrupt_queue(vcpu);
                         break;
                 case INTR_TYPE_HARD_EXCEPTION:
+                        if (vmx->idt_vectoring_info &
+                            VECTORING_INFO_DELIVER_CODE_MASK) {
+                                has_error_code = true;
+                                error_code =
+                                        vmcs_read32(IDT_VECTORING_ERROR_CODE);
+                        }
+                        /* fall through */
                 case INTR_TYPE_SOFT_EXCEPTION:
                         kvm_clear_exception_queue(vcpu);
                         break;
@@ -3307,7 +3316,8 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
                        type != INTR_TYPE_NMI_INTR))
                 skip_emulated_instruction(vcpu);
 
-        if (!kvm_task_switch(vcpu, tss_selector, reason))
+        if (!kvm_task_switch(vcpu, tss_selector, reason, has_error_code,
+                             error_code))
                 return 0;
 
         /* clear all local breakpoint enable flags */