KVM: nVMX: clean up nested_release_vmcs12 and code around it

Make nested_release_vmcs12 idempotent.

Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 21 insertions, 21 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 462334eaa3c0..3300f4f2da48 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6109,20 +6109,27 @@ static int nested_vmx_check_permission(struct kvm_vcpu *vcpu)
 static inline void nested_release_vmcs12(struct vcpu_vmx *vmx)
 {
         u32 exec_control;
+        if (vmx->nested.current_vmptr == -1ull)
+                return;
+
+        /* current_vmptr and current_vmcs12 are always set/reset together */
+        if (WARN_ON(vmx->nested.current_vmcs12 == NULL))
+                return;
+
         if (enable_shadow_vmcs) {
-                if (vmx->nested.current_vmcs12 != NULL) {
-                        /* copy to memory all shadowed fields in case
-                           they were modified */
-                        copy_shadow_to_vmcs12(vmx);
-                        vmx->nested.sync_shadow_vmcs = false;
-                        exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
-                        exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
-                        vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
-                        vmcs_write64(VMCS_LINK_POINTER, -1ull);
-                }
+                /* copy to memory all shadowed fields in case
+                   they were modified */
+                copy_shadow_to_vmcs12(vmx);
+                vmx->nested.sync_shadow_vmcs = false;
+                exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
+                exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
+                vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
+                vmcs_write64(VMCS_LINK_POINTER, -1ull);
         }
         kunmap(vmx->nested.current_vmcs12_page);
         nested_release_page(vmx->nested.current_vmcs12_page);
+        vmx->nested.current_vmptr = -1ull;
+        vmx->nested.current_vmcs12 = NULL;
 }
 
 /*
@@ -6133,12 +6140,9 @@ static void free_nested(struct vcpu_vmx *vmx)
 {
         if (!vmx->nested.vmxon)
                 return;
+
         vmx->nested.vmxon = false;
-        if (vmx->nested.current_vmptr != -1ull) {
-                nested_release_vmcs12(vmx);
-                vmx->nested.current_vmptr = -1ull;
-                vmx->nested.current_vmcs12 = NULL;
-        }
+        nested_release_vmcs12(vmx);
         if (enable_shadow_vmcs)
                 free_vmcs(vmx->nested.current_shadow_vmcs);
         /* Unpin physical memory we referred to in current vmcs02 */
@@ -6175,11 +6179,8 @@ static int handle_vmclear(struct kvm_vcpu *vcpu)
         if (nested_vmx_check_vmptr(vcpu, EXIT_REASON_VMCLEAR, &vmptr))
                 return 1;
 
-        if (vmptr == vmx->nested.current_vmptr) {
+        if (vmptr == vmx->nested.current_vmptr)
                 nested_release_vmcs12(vmx);
-                vmx->nested.current_vmptr = -1ull;
-                vmx->nested.current_vmcs12 = NULL;
-        }
 
         page = nested_get_page(vcpu, vmptr);
         if (page == NULL) {
@@ -6521,9 +6522,8 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
                         skip_emulated_instruction(vcpu);
                         return 1;
                 }
-                if (vmx->nested.current_vmptr != -1ull)
-                        nested_release_vmcs12(vmx);
 
+                nested_release_vmcs12(vmx);
                 vmx->nested.current_vmptr = vmptr;
                 vmx->nested.current_vmcs12 = new_vmcs12;
                 vmx->nested.current_vmcs12_page = page;