From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD2BCC433DF for ; Tue, 11 Aug 2020 12:03:14 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 89C192075D for ; Tue, 11 Aug 2020 12:03:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="R+ECLTVR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89C192075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45468 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k5Szp-0006KD-Lk for qemu-devel@archiver.kernel.org; Tue, 11 Aug 2020 08:03:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59668) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5Sz3-0005s2-PT for qemu-devel@nongnu.org; Tue, 11 Aug 2020 08:02:25 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:26335 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k5Sz0-0002Dk-RG for qemu-devel@nongnu.org; Tue, 11 Aug 2020 08:02:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597147341; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=XRE32AsdoxPjsDiqDcFNatTyYtDw1PEuBrES1gt7Vas=; b=R+ECLTVRCLK1XtHeTiqh6p8fG+HkHmcggt8Vh5VrN1wsen02JIfJLKx2l/jfAvd2DX7zFr xW2+hWcPn/B7XuX/Rv8sfwkAyay1cDHvScsvRIXrrGOdpgW9zwGBS9S88OV+vScluOVugt hqXVeHfTUoegprFQEwwgRcZTX5cBEek= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-541-akHCSct9M5ezJP-CgLkTJQ-1; Tue, 11 Aug 2020 08:02:19 -0400 X-MC-Unique: akHCSct9M5ezJP-CgLkTJQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DF0621009443; Tue, 11 Aug 2020 12:02:17 +0000 (UTC) Received: from [10.36.112.235] (ovpn-112-235.ams2.redhat.com [10.36.112.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id DDDD56F136; Tue, 11 Aug 2020 12:02:07 +0000 (UTC) Subject: Re: [PATCH v2] virtio-rng: return available data with O_NONBLOCK To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , mwilck@suse.com, "Michael S. Tsirkin" , Jason Wang References: <20200715133255.10526-1-mwilck@suse.com> <7cfc4316-922b-8606-72ce-80205ef55572@redhat.com> From: Laurent Vivier Autocrypt: addr=lvivier@redhat.com; prefer-encrypt=mutual; keydata= mQINBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABtCNMYXVyZW50IFZp dmllciA8bHZpdmllckByZWRoYXQuY29tPokCOAQTAQIAIgUCVgVQgAIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjwpgg//fSGy0Rs/t8cPFuzoY1cex4limJQfReLr SJXCANg9NOWy/bFK5wunj+h/RCFxIFhZcyXveurkBwYikDPUrBoBRoOJY/BHK0iZo7/WQkur 6H5losVZtrotmKOGnP/lJYZ3H6OWvXzdz8LL5hb3TvGOP68K8Bn8UsIaZJoeiKhaNR0sOJyI YYbgFQPWMHfVwHD/U+/gqRhD7apVysxv5by/pKDln1I5v0cRRH6hd8M8oXgKhF2+rAOL7gvh jEHSSWKUlMjC7YwwjSZmUkL+TQyE18e2XBk85X8Da3FznrLiHZFHQ/NzETYxRjnOzD7/kOVy gKD/o7asyWQVU65mh/ECrtjfhtCBSYmIIVkopoLaVJ/kEbVJQegT2P6NgERC/31kmTF69vn8 uQyW11Hk8tyubicByL3/XVBrq4jZdJW3cePNJbTNaT0d/bjMg5zCWHbMErUib2Nellnbg6bc 2HLDe0NLVPuRZhHUHM9hO/JNnHfvgiRQDh6loNOUnm9Iw2YiVgZNnT4soUehMZ7au8PwSl4I KYE4ulJ8RRiydN7fES3IZWmOPlyskp1QMQBD/w16o+lEtY6HSFEzsK3o0vuBRBVp2WKnssVH qeeV01ZHw0bvWKjxVNOksP98eJfWLfV9l9e7s6TaAeySKRRubtJ+21PRuYAxKsaueBfUE7ZT 7ze0LUxhdXJlbnQgVml2aWVyIChSZWQgSGF0KSA8bHZpdmllckByZWRoYXQuY29tPokCOAQT AQIAIgUCVgUmGQIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjxtNBAA o2xGmbXl9vJQALkj7MVlsMlgewQ1rdoZl+bZ6ythTSBsqwwtl1BUTQGA1GF2LAchRVYca5bJ lw4ai5OdZ/rc5dco2XgrRFtj1np703BzNEhGU1EFxtms/Y9YOobq/GZpck5rK8jV4osEb8oc 3xEgCm/xFwI/2DOe0/s2cHKzRkvdmKWEDhT1M+7UhtSCnloX776zCsrofYiHP2kasFyMa/5R 9J1Rt9Ax/jEAX5vFJ8+NPf68497nBfrAtLM3Xp03YJSr/LDxer44Mevhz8dFw7IMRLhnuSfr 8jP93lr6Wa8zOe3pGmFXZWpNdkV/L0HaeKwTyDKKdUDH4U7SBnE1gcDfe9x08G+oDfVhqED8 qStKCxPYxRUKIdUjGPF3f5oj7N56Q5zZaZkfxeLNTQ13LDt3wGbVHyZxzFc81B+qT8mkm74y RbeVSuviPTYjbBQ66GsUgiZZpDUyJ6s54fWqQdJf4VFwd7M/mS8WEejbSjglGHMxMGiBeRik Y0+ur5KAF7z0D1KfW1kHO9ImQ0FbEbMbTMf9u2+QOCrSWOz/rj23EwPrCQ2TSRI2fWakMJZ+ zQZvy+ei3D7lZ09I9BT/GfFkTIONgtNfDxwyMc4v4XyP0IvvZs/YZqt7j3atyTZM0S2HSaZ9 rXmQYkBt1/u691cZfvy+Tr2xZaDpFcjPkci5Ag0EVgUmGQEQALxSQRbl/QOnmssVDxWhHM5T Gxl7oLNJms2zmBpcmlrIsn8nNz0rRyxT460k2niaTwowSRK8KWVDeAW6ZAaWiYjLlTunoKwv F8vP3JyWpBz0diTxL5o+xpvy/Q6YU3BNefdq8Vy3rFsxgW7mMSrI/CxJ667y8ot5DVugeS2N yHfmZlPGE0Nsy7hlebS4liisXOrN3jFzasKyUws3VXek4V65lHwB23BVzsnFMn/bw/rPliqX Gcwl8CoJu8dSyrCcd1Ibs0/Inq9S9+t0VmWiQWfQkz4rvEeTQkp/VfgZ6z98JRW7S6l6eoph oWs0/ZyRfOm+QVSqRfFZdxdP2PlGeIFMC3fXJgygXJkFPyWkVElr76JTbtSHsGWbt6xUlYHK XWo+xf9WgtLeby3cfSkEchACrxDrQpj+Jt/JFP+q997dybkyZ5IoHWuPkn7uZGBrKIHmBunT co1+cKSuRiSCYpBIXZMHCzPgVDjk4viPbrV9NwRkmaOxVvye0vctJeWvJ6KA7NoAURplIGCq kCRwg0MmLrfoZnK/gRqVJ/f6adhU1oo6z4p2/z3PemA0C0ANatgHgBb90cd16AUxpdEQmOCm dNnNJF/3Zt3inzF+NFzHoM5Vwq6rc1JPjfC3oqRLJzqAEHBDjQFlqNR3IFCIAo4SYQRBdAHB CzkM4rWyRhuVABEBAAGJAh8EGAECAAkFAlYFJhkCGwwACgkQ8ww4vT8vvjwg9w//VQrcnVg3 TsjEybxDEUBm8dBmnKqcnTBFmxN5FFtIWlEuY8+YMiWRykd8Ln9RJ/98/ghABHz9TN8TRo2b 6WimV64FmlVn17Ri6FgFU3xNt9TTEChqAcNg88eYryKsYpFwegGpwUlaUaaGh1m9OrTzcQy+ klVfZWaVJ9Nw0keoGRGb8j4XjVpL8+2xOhXKrM1fzzb8JtAuSbuzZSQPDwQEI5CKKxp7zf76 J21YeRrEW4WDznPyVcDTa+tz++q2S/BpP4W98bXCBIuQgs2m+OflERv5c3Ojldp04/S4NEjX EYRWdiCxN7ca5iPml5gLtuvhJMSy36glU6IW9kn30IWuSoBpTkgV7rLUEhh9Ms82VWW/h2Tx L8enfx40PrfbDtWwqRID3WY8jLrjKfTdR3LW8BnUDNkG+c4FzvvGUs8AvuqxxyHbXAfDx9o/ jXfPHVRmJVhSmd+hC3mcQ+4iX5bBPBPMoDqSoLt5w9GoQQ6gDVP2ZjTWqwSRMLzNr37rJjZ1 pt0DCMMTbiYIUcrhX8eveCJtY7NGWNyxFCRkhxRuGcpwPmRVDwOl39MB3iTsRighiMnijkbL XiKoJ5CDVvX5yicNqYJPKh5MFXN1bvsBkmYiStMRbrD0HoY1kx5/VozBtc70OU0EB8Wrv9hZ D+Ofp0T3KOr1RUHvCZoLURfFhSQ= Message-ID: <7affb721-9686-1262-b7cf-d9681646b602@redhat.com> Date: Tue, 11 Aug 2020 14:02:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <7cfc4316-922b-8606-72ce-80205ef55572@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lvivier@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=lvivier@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/11 04:41:55 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Amit Shah , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/08/2020 12:37, Philippe Mathieu-Daudé wrote: > You Cc'ed qemu-devel, so Cc'ing the virtio-rng maintainers. > > On 7/15/20 3:32 PM, mwilck@suse.com wrote: >> From: Martin Wilck >> >> If a program opens /dev/hwrng with O_NONBLOCK and uses poll() and >> non-blocking read() to retrieve random data, it ends up in a tight >> loop with poll() always returning POLLIN and read() returning EAGAIN. >> This repeats forever until some process makes a blocking read() call. >> The reason is that virtio_read() always returns 0 in non-blocking mode, >> even if data is available. Worse, it fetches random data from the >> hypervisor after every non-blocking call, without ever using this data. >> >> The following test program illustrates the behavior and can be used >> for testing and experiments. The problem will only be seen if all >> tasks use non-blocking access; otherwise the blocking reads will >> "recharge" the random pool and cause other, non-blocking reads to >> succeed at least sometimes. >> >> /* Whether to use non-blocking mode in a task, problem occurs if CONDITION is 1 */ >> //#define CONDITION (getpid() % 2 != 0) >> >> static volatile sig_atomic_t stop; >> static void handler(int sig __attribute__((unused))) { stop = 1; } >> >> static void loop(int fd, int sec) >> { >> struct pollfd pfd = { .fd = fd, .events = POLLIN, }; >> unsigned long errors = 0, eagains = 0, bytes = 0, succ = 0; >> int size, rc, rd; >> >> srandom(getpid()); >> if (CONDITION && fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK) == -1) >> perror("fcntl"); >> size = MINBUFSIZ + random() % (MAXBUFSIZ - MINBUFSIZ + 1); >> >> for(;;) { >> char buf[size]; >> >> if (stop) >> break; >> rc = poll(&pfd, 1, sec); >> if (rc > 0) { >> rd = read(fd, buf, sizeof(buf)); >> if (rd == -1 && errno == EAGAIN) >> eagains++; >> else if (rd == -1) >> errors++; >> else { >> succ++; >> bytes += rd; >> write(1, buf, sizeof(buf)); >> } >> } else if (rc == -1) { >> if (errno != EINTR) >> perror("poll"); >> break; >> } else >> fprintf(stderr, "poll: timeout\n"); >> } >> fprintf(stderr, >> "pid %d %sblocking, bufsize %d, %d seconds, %lu bytes read, %lu success, %lu eagain, %lu errors\n", >> getpid(), CONDITION ? "non-" : "", size, sec, bytes, succ, eagains, errors); >> } >> >> int main(void) >> { >> int fd; >> >> fork(); fork(); >> fd = open("/dev/hwrng", O_RDONLY); >> if (fd == -1) { >> perror("open"); >> return 1; >> }; >> signal(SIGALRM, handler); >> alarm(SECONDS); >> loop(fd, SECONDS); >> close(fd); >> wait(NULL); >> return 0; >> } >> >> void loop(int fd) >> { >> struct pollfd pfd0 = { .fd = fd, .events = POLLIN, }; >> int rc; >> unsigned int n; >> >> for (n = LOOPS; n > 0; n--) { >> struct pollfd pfd = pfd0; >> char buf[SIZE]; >> >> rc = poll(&pfd, 1, 1); >> if (rc > 0) { >> int rd = read(fd, buf, sizeof(buf)); >> >> if (rd == -1) >> perror("read"); >> else >> printf("read %d bytes\n", rd); >> } else if (rc == -1) >> perror("poll"); >> else >> fprintf(stderr, "timeout\n"); >> >> } >> } >> >> int main(void) >> { >> int fd; >> >> fd = open("/dev/hwrng", O_RDONLY|O_NONBLOCK); >> if (fd == -1) { >> perror("open"); >> return 1; >> }; >> loop(fd); >> close(fd); >> return 0; >> } >> >> This can be observed in the real word e.g. with nested qemu/KVM virtual >> machines, if both the "outer" and "inner" VMs have a virtio-rng device. >> If the "inner" VM requests random data, qemu running in the "outer" VM >> uses this device in a non-blocking manner like the test program above. >> >> Fix it by returning available data if a previous hypervisor call has >> completed in the meantime. I tested the patch with the program above, >> and with rng-tools. >> >> Signed-off-by: Martin Wilck >> --- >> drivers/char/hw_random/virtio-rng.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c >> index 79a6e47b5fbc..984713b35892 100644 >> --- a/drivers/char/hw_random/virtio-rng.c >> +++ b/drivers/char/hw_random/virtio-rng.c >> @@ -59,6 +59,20 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) >> if (vi->hwrng_removed) >> return -ENODEV; >> >> + /* >> + * If the previous call was non-blocking, we may have got some >> + * randomness already. >> + */ >> + if (vi->busy && completion_done(&vi->have_data)) { >> + unsigned int len; >> + >> + vi->busy = false; >> + len = vi->data_avail > size ? size : vi->data_avail; >> + vi->data_avail -= len; You don't need to modify data_avail. As busy is set to false, the buffer will be reused. and it is always overwritten by virtqueue_get_buf(). And moreover, if it was reused it would be always the beginning. >> + if (len) >> + return len; >> + } >> + >> if (!vi->busy) { >> vi->busy = true; >> reinit_completion(&vi->have_data); >> > Why don't you modify only the wait case? Something like: if (!wait && !completion_done(&vi->have_data)) { return 0; } then at the end you can do "return min(size, vi->data_avail);". Thanks, Laurent From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24E20C433E0 for ; Tue, 11 Aug 2020 12:02:39 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E4CB72075D for ; Tue, 11 Aug 2020 12:02:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="R+ECLTVR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4CB72075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id AD49C876A5; Tue, 11 Aug 2020 12:02:38 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Hn7ulXyLtVxY; Tue, 11 Aug 2020 12:02:37 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id E1F44875B7; Tue, 11 Aug 2020 12:02:37 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id D07BAC013C; Tue, 11 Aug 2020 12:02:37 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2D186C004D for ; Tue, 11 Aug 2020 12:02:37 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 162E92154F for ; Tue, 11 Aug 2020 12:02:37 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pQ4eExLIoj5f for ; Tue, 11 Aug 2020 12:02:23 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by silver.osuosl.org (Postfix) with ESMTPS id D090B204EF for ; Tue, 11 Aug 2020 12:02:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597147341; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=XRE32AsdoxPjsDiqDcFNatTyYtDw1PEuBrES1gt7Vas=; b=R+ECLTVRCLK1XtHeTiqh6p8fG+HkHmcggt8Vh5VrN1wsen02JIfJLKx2l/jfAvd2DX7zFr xW2+hWcPn/B7XuX/Rv8sfwkAyay1cDHvScsvRIXrrGOdpgW9zwGBS9S88OV+vScluOVugt hqXVeHfTUoegprFQEwwgRcZTX5cBEek= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-541-akHCSct9M5ezJP-CgLkTJQ-1; Tue, 11 Aug 2020 08:02:19 -0400 X-MC-Unique: akHCSct9M5ezJP-CgLkTJQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DF0621009443; Tue, 11 Aug 2020 12:02:17 +0000 (UTC) Received: from [10.36.112.235] (ovpn-112-235.ams2.redhat.com [10.36.112.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id DDDD56F136; Tue, 11 Aug 2020 12:02:07 +0000 (UTC) Subject: Re: [PATCH v2] virtio-rng: return available data with O_NONBLOCK To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , mwilck@suse.com, "Michael S. 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