[PATCH v2 1/3] KVM: nVMX: Fill VM-Exit instruction length before saving pending event

[ma.mandourr@gmail.com]

From: Mahmoud Abumandour <ma.mandourr@gmail.com>

Fill vmcs12's VM-Exit instruction length before calling
vmcs12_save_pending_event(), so that the length it saves for a software
exception isn't overwritten.  Commit c3634d25fbee ("KVM: nVMX: Leave most
VM-Exit info fields unmodified on failed VM-Entry") moved the assignment
after the call.

L1 sees no difference since both lengths are read from vmcs02's VM-Exit
instruction length.

Link: https://lore.kernel.org/all/sashiko-outbox-179791@kernel.org
Signed-off-by: Mahmoud Abumandour <ma.mandourr@gmail.com>
---
 arch/x86/kvm/vmx/nested.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 9b0bfa2f854c..6f7c00083beb 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4764,6 +4764,9 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 		 * instead of reading the real value. */
 		vmcs12->vm_entry_intr_info_field &= ~INTR_INFO_VALID_MASK;
 
+		/* vmcs12_save_pending_event() may override this. */
+		vmcs12->vm_exit_instruction_len = exit_insn_len;
+
 		/*
 		 * Transfer the event that L0 or L1 may wanted to inject into
 		 * L2 to IDT_VECTORING_INFO_FIELD.
@@ -4772,7 +4775,6 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 					  vm_exit_reason, exit_intr_info);
 
 		vmcs12->vm_exit_intr_info = exit_intr_info;
-		vmcs12->vm_exit_instruction_len = exit_insn_len;
 		vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
 
 		/*
-- 
2.43.0