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Thu, 24 Oct 2019 09:10:07 +0000 Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x9O9A7Bh001853; Thu, 24 Oct 2019 09:10:07 GMT Received: from jaraman-bur-1.us.oracle.com (/10.152.33.39) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 24 Oct 2019 02:10:06 -0700 From: Jagannathan Raman To: qemu-devel@nongnu.org Subject: [RFC v4 PATCH 08/49] multi-process: add functions to synchronize proxy and remote endpoints Date: Thu, 24 Oct 2019 05:08:49 -0400 Message-Id: <823727c8cf4bbc563cecebd6a231bea77d81adeb.1571905346.git.jag.raman@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9419 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910240089 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9419 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910240089 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 156.151.31.86 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: elena.ufimtseva@oracle.com, fam@euphon.net, john.g.johnson@oracle.com, kraxel@redhat.com, jag.raman@oracle.com, quintela@redhat.com, mst@redhat.com, armbru@redhat.com, kanth.ghatraju@oracle.com, thuth@redhat.com, ehabkost@redhat.com, konrad.wilk@oracle.com, dgilbert@redhat.com, liran.alon@oracle.com, stefanha@redhat.com, rth@twiddle.net, kwolf@redhat.com, berrange@redhat.com, mreitz@redhat.com, ross.lagerwall@citrix.com, marcandre.lureau@gmail.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" In some cases, for example MMIO read, QEMU has to wait for the remote to complete a command before proceeding. An eventfd based mechanism is added to synchronize QEMU & remote process. Signed-off-by: John G Johnson Signed-off-by: Jagannathan Raman Signed-off-by: Elena Ufimtseva --- v1 -> v2: - Added timeout to synchronization functions include/io/mpqemu-link.h | 9 +++++++++ io/mpqemu-link.c | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/include/io/mpqemu-link.h b/include/io/mpqemu-link.h index 345c67e..dee2dd3 100644 --- a/include/io/mpqemu-link.h +++ b/include/io/mpqemu-link.h @@ -30,7 +30,9 @@ #include #include +#include #include +#include #include "qom/object.h" #include "qemu/thread.h" @@ -147,4 +149,11 @@ void mpqemu_destroy_channel(MPQemuChannel *chan); void mpqemu_link_set_callback(MPQemuLinkState *s, mpqemu_link_callback callback); void mpqemu_start_coms(MPQemuLinkState *s); +#define GET_REMOTE_WAIT eventfd(0, 0) +#define PUT_REMOTE_WAIT(wait) close(wait) +#define PROXY_LINK_WAIT_DONE 1 + +uint64_t wait_for_remote(int efd); +void notify_proxy(int fd, uint64_t val); + #endif diff --git a/io/mpqemu-link.c b/io/mpqemu-link.c index b39f4d0..696aeb1 100644 --- a/io/mpqemu-link.c +++ b/io/mpqemu-link.c @@ -231,6 +231,46 @@ int mpqemu_msg_recv(MPQemuLinkState *s, MPQemuMsg *msg, MPQemuChannel *chan) return rc; } +uint64_t wait_for_remote(int efd) +{ + struct pollfd pfd = { .fd = efd, .events = POLLIN }; + uint64_t val; + int ret; + + ret = poll(&pfd, 1, 1000); + + switch (ret) { + case 0: + qemu_log_mask(LOG_REMOTE_DEBUG, "Error wait_for_remote: Timed out\n"); + /* TODO: Kick-off error recovery */ + return ULLONG_MAX; + case -1: + qemu_log_mask(LOG_REMOTE_DEBUG, "Poll error wait_for_remote: %s\n", + strerror(errno)); + return ULLONG_MAX; + default: + if (read(efd, &val, sizeof(val)) == -1) { + qemu_log_mask(LOG_REMOTE_DEBUG, "Error wait_for_remote: %s\n", + strerror(errno)); + return ULLONG_MAX; + } + } + + val = (val == ULLONG_MAX) ? val : (val - 1); + + return val; +} + +void notify_proxy(int efd, uint64_t val) +{ + val = (val == ULLONG_MAX) ? val : (val + 1); + + if (write(efd, &val, sizeof(val)) == -1) { + qemu_log_mask(LOG_REMOTE_DEBUG, "Error notify_proxy: %s\n", + strerror(errno)); + } +} + static gboolean mpqemu_link_handler_prepare(GSource *gsrc, gint *timeout) { g_assert(timeout);