113 lines
3.5 KiB
Diff
113 lines
3.5 KiB
Diff
From 92aff3cc1a412de01e9563802fa48848eae5283f Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
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Date: Thu, 21 Dec 2023 16:58:41 +0100
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Subject: [PATCH 065/101] backends/iommufd: Remove mutex
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Eric Auger <eric.auger@redhat.com>
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RH-MergeRequest: 211: IOMMUFD backend backport
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RH-Jira: RHEL-19302 RHEL-21057
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RH-Acked-by: Cédric Le Goater <clg@redhat.com>
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RH-Acked-by: Sebastian Ott <sebott@redhat.com>
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RH-Commit: [64/67] 65518432b18f18ceadafe1b0698cdaa962e84f61 (eauger1/centos-qemu-kvm)
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Coverity reports a concurrent data access violation because be->users
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is being accessed in iommufd_backend_can_be_deleted() without holding
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the mutex.
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However, these routines are called from the QEMU main thread when a
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device is created. In this case, the code paths should be protected by
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the BQL lock and it should be safe to drop the IOMMUFD backend mutex.
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Simply remove it.
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Fixes: CID 1531550
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Fixes: CID 1531549
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Reviewed-by: Eric Auger <eric.auger@redhat.com>
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Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
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Signed-off-by: Cédric Le Goater <clg@redhat.com>
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(cherry picked from commit 19368b1905b4b917e915526fcbd5bfa3f7439451)
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Signed-off-by: Eric Auger <eric.auger@redhat.com>
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---
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backends/iommufd.c | 7 -------
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include/sysemu/iommufd.h | 2 --
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2 files changed, 9 deletions(-)
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diff --git a/backends/iommufd.c b/backends/iommufd.c
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index 393c0d9a37..1ef683c7b0 100644
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--- a/backends/iommufd.c
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+++ b/backends/iommufd.c
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@@ -29,7 +29,6 @@ static void iommufd_backend_init(Object *obj)
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be->fd = -1;
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be->users = 0;
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be->owned = true;
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- qemu_mutex_init(&be->lock);
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}
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static void iommufd_backend_finalize(Object *obj)
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@@ -52,10 +51,8 @@ static void iommufd_backend_set_fd(Object *obj, const char *str, Error **errp)
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error_prepend(errp, "Could not parse remote object fd %s:", str);
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return;
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}
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- qemu_mutex_lock(&be->lock);
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be->fd = fd;
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be->owned = false;
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- qemu_mutex_unlock(&be->lock);
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trace_iommu_backend_set_fd(be->fd);
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}
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@@ -79,7 +76,6 @@ int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
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{
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int fd, ret = 0;
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- qemu_mutex_lock(&be->lock);
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if (be->owned && !be->users) {
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fd = qemu_open_old("/dev/iommu", O_RDWR);
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if (fd < 0) {
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@@ -93,13 +89,11 @@ int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
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out:
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trace_iommufd_backend_connect(be->fd, be->owned,
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be->users, ret);
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- qemu_mutex_unlock(&be->lock);
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return ret;
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}
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void iommufd_backend_disconnect(IOMMUFDBackend *be)
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{
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- qemu_mutex_lock(&be->lock);
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if (!be->users) {
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goto out;
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}
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@@ -110,7 +104,6 @@ void iommufd_backend_disconnect(IOMMUFDBackend *be)
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}
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out:
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trace_iommufd_backend_disconnect(be->fd, be->users);
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- qemu_mutex_unlock(&be->lock);
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}
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int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
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diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
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index 9c5524b0ed..9af27ebd6c 100644
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--- a/include/sysemu/iommufd.h
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+++ b/include/sysemu/iommufd.h
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@@ -2,7 +2,6 @@
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#define SYSEMU_IOMMUFD_H
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#include "qom/object.h"
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-#include "qemu/thread.h"
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#include "exec/hwaddr.h"
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#include "exec/cpu-common.h"
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@@ -19,7 +18,6 @@ struct IOMMUFDBackend {
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/*< protected >*/
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int fd; /* /dev/iommu file descriptor */
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bool owned; /* is the /dev/iommu opened internally */
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- QemuMutex lock;
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uint32_t users;
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/*< public >*/
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--
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2.39.3
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