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>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 462334eaa3c008acefe7e26729e7e7f7dbe54bf6..3300f4f2da486c83d239778c1b3cc92609e61cbb 100644 (file)
--- 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;