From patchwork Thu Jan 23 03:00:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 11346715 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E344617EF for ; Thu, 23 Jan 2020 02:58:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5F4D24125 for ; Thu, 23 Jan 2020 02:58:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726118AbgAWC60 (ORCPT ); Wed, 22 Jan 2020 21:58:26 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:47510 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725911AbgAWC60 (ORCPT ); Wed, 22 Jan 2020 21:58:26 -0500 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id ABB2152DA18A987470E2; Thu, 23 Jan 2020 10:58:23 +0800 (CST) Received: from huawei.com (10.175.105.18) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Thu, 23 Jan 2020 10:58:13 +0800 From: linmiaohe To: , , , , , , , , , , CC: , , , Subject: [PATCH] KVM: x86: avoid some unnecessary copy in __x86_set_memory_region() Date: Thu, 23 Jan 2020 11:00:13 +0800 Message-ID: <1579748413-432-1-git-send-email-linmiaohe@huawei.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 X-Originating-IP: [10.175.105.18] X-CFilter-Loop: Reflected Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Miaohe Lin Only userspace_addr and npages are passed to vm_munmap() when remove a memory region. So we shouldn't copy the integral kvm_memory_slot struct. No functional change intended. Signed-off-by: Miaohe Lin Reported-by: kbuild test robot --- arch/x86/kvm/x86.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d1faa74981d9..767f29877938 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9735,9 +9735,9 @@ void kvm_arch_sync_events(struct kvm *kvm) int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) { int i, r; - unsigned long hva; + unsigned long hva, uaddr, npages; struct kvm_memslots *slots = kvm_memslots(kvm); - struct kvm_memory_slot *slot, old; + struct kvm_memory_slot *slot; /* Called with kvm->slots_lock held. */ if (WARN_ON(id >= KVM_MEM_SLOTS_NUM)) @@ -9761,9 +9761,10 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) return 0; hva = 0; + uaddr = slot->userspace_addr; + npages = slot->npages; } - old = *slot; for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { struct kvm_userspace_memory_region m; @@ -9778,7 +9779,7 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) } if (!size) - vm_munmap(old.userspace_addr, old.npages * PAGE_SIZE); + vm_munmap(uaddr, npages * PAGE_SIZE); return 0; }