KVM: s390: pv: destroy the configuration before its memory

Move the Destroy Secure Configuration UVC before the loop to destroy the memory. If the protected VM has memory, it will be cleaned up and made accessible by the Destroy Secure Configuration UVC. The struct page for the relevant pages will still have the protected bit set, so the loop is still needed to clean that up. Switching the order of those two operations does not change the outcome, but it is significantly faster. Signed-off-by: Claudio Imbrenda <[email protected]> Reviewed-by: Nico Boehr <[email protected]> Reviewed-by: Janosch Frank <[email protected]> Link: https://lore.kernel.org/r/[email protected] Message-Id: <[email protected]> Signed-off-by: Janosch Frank <[email protected]>
ambv · Jul 19, 2022 · 7746f73 · 7746f73
1 parent da15fbc
commit 7746f73
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
@@ -164,6 +164,9 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 {
 	int cc;
 
+	cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
+			   UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
+	WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
 	/*
 	 * if the mm still has a mapping, make all its pages accessible
 	 * before destroying the guest
@@ -173,9 +176,6 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 		mmput(kvm->mm);
 	}
 
-	cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
-			   UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
-	WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
 	if (!cc) {
 		atomic_dec(&kvm->mm->context.protected_count);
 		kvm_s390_pv_dealloc_vm(kvm);