From patchwork Thu Apr 16 15:59:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11493327 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 4EBDF81 for ; Thu, 16 Apr 2020 15:59:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36C8321924 for ; Thu, 16 Apr 2020 15:59:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OeXEN1TV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406733AbgDPP71 (ORCPT ); Thu, 16 Apr 2020 11:59:27 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:23679 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2897213AbgDPP7N (ORCPT ); Thu, 16 Apr 2020 11:59:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587052752; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=toq7sOeh3Oxre7YgXmyZ7yZ/oSgoiV55xEipFX9W/e8=; b=OeXEN1TVB2gqjwV47bMW3I7tbfhsDT5KORnwTppfZajqlXqlGU1RHhB5oZsDVoj0QaiUUT jkfcKARjNsfVspB13/kizegYJX8nIELEcZyJbE0xquJf2MaBka6x2OAcqEdLRv17pHK4WD RnomzhuyNHdqgjXrBXW+TcFMoB0e5/E= Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-36-y9Rb8g2tOSmEN8P-n19jDg-1; Thu, 16 Apr 2020 11:59:10 -0400 X-MC-Unique: y9Rb8g2tOSmEN8P-n19jDg-1 Received: by mail-qk1-f200.google.com with SMTP id r129so12931547qkd.19 for ; Thu, 16 Apr 2020 08:59:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=toq7sOeh3Oxre7YgXmyZ7yZ/oSgoiV55xEipFX9W/e8=; b=hzjHNA02gKy3Z3B65bOI6zT0vem6wjqo5EK0R3pzDjijvn5wLTBqpBSCgE/tTECR2a 7OTJsmDgOeIZkxp7mLBUHK72MqDv5tpgvzlNXsnwbBx35iEWXQq6YlFNyGrHhnTLoUBC QwNZyxoW2MlVe4xwG7Ll+CXVViePLSVVi5yC2wOskySrCDH0dV+K+IzXdJcAVZ0F+77D 0A2LcrErttyVcHD4zhvM8XJy5rpow8I1+g/Ui1Uy+Jva0XbDM/1OOgH800QT31WEEoou nGVKUpNHtkzifV3l2Yq+Dr5qRAUiszpmndddOa7PkJEY7Z/R9/+HkHmFbhYUjpLV3VjZ QNjA== X-Gm-Message-State: AGi0PuYoUKeI65XneH4O5Fy8+S7Hr1rDf4h3OlCoHfMz37s+putRXan1 1wId+dQ71KxpoNNNRIo+2ElCwT7rNLbTev3bLNzmivDQcw8+mnLzvcQ6Gynth3Klk3sVdyhDxWu FlbLdYfenSW/r X-Received: by 2002:a37:6754:: with SMTP id b81mr11643863qkc.129.1587052748954; Thu, 16 Apr 2020 08:59:08 -0700 (PDT) X-Google-Smtp-Source: APiQypIp14On5d+FqJCkdeoD2L1ux2G7lAjoz3TzLNQDBoXBLDbiX6e/+Ywl75dqRmGHTVCB1srDGQ== X-Received: by 2002:a37:6754:: with SMTP id b81mr11643846qkc.129.1587052748695; Thu, 16 Apr 2020 08:59:08 -0700 (PDT) Received: from xz-x1.redhat.com ([2607:9880:19c0:32::2]) by smtp.gmail.com with ESMTPSA id l7sm15398153qkb.47.2020.04.16.08.59.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Apr 2020 08:59:08 -0700 (PDT) From: Peter Xu To: kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , peterx@redhat.com Subject: [PATCH] KVM: No need to retry for hva_to_pfn_remapped() Date: Thu, 16 Apr 2020 11:59:06 -0400 Message-Id: <20200416155906.267462-1-peterx@redhat.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org hva_to_pfn_remapped() calls fixup_user_fault(), which has already handled the retry gracefully. Even if "unlocked" is set to true, it means that we've got a VM_FAULT_RETRY inside fixup_user_fault(), however the page fault has already retried and we should have the pfn set correctly. No need to do that again. Signed-off-by: Peter Xu --- virt/kvm/kvm_main.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2f1f2f56e93d..6aaed69641a5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1824,8 +1824,6 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma, r = fixup_user_fault(current, current->mm, addr, (write_fault ? FAULT_FLAG_WRITE : 0), &unlocked); - if (unlocked) - return -EAGAIN; if (r) return r; @@ -1896,15 +1894,12 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async, goto exit; } -retry: vma = find_vma_intersection(current->mm, addr, addr + 1); if (vma == NULL) pfn = KVM_PFN_ERR_FAULT; else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) { r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn); - if (r == -EAGAIN) - goto retry; if (r < 0) pfn = KVM_PFN_ERR_FAULT; } else {