From nobody Mon Feb 9 06:34:13 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1489460563841334.5039221329773; Mon, 13 Mar 2017 20:02:43 -0700 (PDT) Received: from localhost ([::1]:56116 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cncjR-0007UA-MV for importer@patchew.org; Mon, 13 Mar 2017 23:02:41 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59035) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cncih-0007Sr-WD for qemu-devel@nongnu.org; Mon, 13 Mar 2017 23:01:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cncig-0002VU-M2 for qemu-devel@nongnu.org; Mon, 13 Mar 2017 23:01:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57320) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cncig-0002VJ-EK for qemu-devel@nongnu.org; Mon, 13 Mar 2017 23:01:54 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 83E9F3B721; Tue, 14 Mar 2017 03:01:54 +0000 (UTC) Received: from jason-ThinkPad-T450s.redhat.com (vpn1-6-24.pek2.redhat.com [10.72.6.24]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v2E31kkO030343; Mon, 13 Mar 2017 23:01:52 -0400 From: Jason Wang To: mst@redhat.com, qemu-devel@nongnu.org Date: Tue, 14 Mar 2017 11:01:41 +0800 Message-Id: <1489460502-6686-3-git-send-email-jasowang@redhat.com> In-Reply-To: <1489460502-6686-1-git-send-email-jasowang@redhat.com> References: <1489460502-6686-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 14 Mar 2017 03:01:54 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH V3 2/3] virtio: destroy region cache during reset X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Cornelia Huck , Paolo Bonzini , Jason Wang Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We don't destroy region cache during reset which can make the maps of previous driver leaked to a buggy or malicious driver that don't set vring address before starting to use the device. Fix this by destroy the region cache during reset and validate it before trying to see them. Cc: Cornelia Huck Cc: Paolo Bonzini Signed-off-by: Jason Wang Reviewed-by: Cornelia Huck --- Changes from V2: - introduce a helper and assert caches !=3D NULL Changes from v1: - switch to use rcu in virtio_virtqueue_region_cache() - use unlikely() when needed --- hw/virtio/virtio.c | 46 ++++++++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 16 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 9164579..f607a09 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -185,10 +185,16 @@ static void vring_desc_read(VirtIODevice *vdev, VRing= Desc *desc, virtio_tswap16s(vdev, &desc->next); } =20 +static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *= vq) +{ + VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + assert(caches !=3D NULL); + return caches; +} /* Called within rcu_read_lock(). */ static inline uint16_t vring_avail_flags(VirtQueue *vq) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingAvail, flags); return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); } @@ -196,7 +202,7 @@ static inline uint16_t vring_avail_flags(VirtQueue *vq) /* Called within rcu_read_lock(). */ static inline uint16_t vring_avail_idx(VirtQueue *vq) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingAvail, idx); vq->shadow_avail_idx =3D virtio_lduw_phys_cached(vq->vdev, &caches->av= ail, pa); return vq->shadow_avail_idx; @@ -205,7 +211,7 @@ static inline uint16_t vring_avail_idx(VirtQueue *vq) /* Called within rcu_read_lock(). */ static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingAvail, ring[i]); return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); } @@ -220,7 +226,7 @@ static inline uint16_t vring_get_used_event(VirtQueue *= vq) static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem, int i) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingUsed, ring[i]); virtio_tswap32s(vq->vdev, &uelem->id); virtio_tswap32s(vq->vdev, &uelem->len); @@ -231,7 +237,7 @@ static inline void vring_used_write(VirtQueue *vq, VRin= gUsedElem *uelem, /* Called within rcu_read_lock(). */ static uint16_t vring_used_idx(VirtQueue *vq) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingUsed, idx); return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); } @@ -239,7 +245,7 @@ static uint16_t vring_used_idx(VirtQueue *vq) /* Called within rcu_read_lock(). */ static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); hwaddr pa =3D offsetof(VRingUsed, idx); virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val); address_space_cache_invalidate(&caches->used, pa, sizeof(val)); @@ -249,11 +255,10 @@ static inline void vring_used_idx_set(VirtQueue *vq, = uint16_t val) /* Called within rcu_read_lock(). */ static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); VirtIODevice *vdev =3D vq->vdev; hwaddr pa =3D offsetof(VRingUsed, flags); uint16_t flags =3D virtio_lduw_phys_cached(vq->vdev, &caches->used, pa= ); - virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask); address_space_cache_invalidate(&caches->used, pa, sizeof(flags)); } @@ -261,7 +266,7 @@ static inline void vring_used_flags_set_bit(VirtQueue *= vq, int mask) /* Called within rcu_read_lock(). */ static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) { - VRingMemoryRegionCaches *caches =3D atomic_rcu_read(&vq->vring.caches); + VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); VirtIODevice *vdev =3D vq->vdev; hwaddr pa =3D offsetof(VRingUsed, flags); uint16_t flags =3D virtio_lduw_phys_cached(vq->vdev, &caches->used, pa= ); @@ -279,7 +284,7 @@ static inline void vring_set_avail_event(VirtQueue *vq,= uint16_t val) return; } =20 - caches =3D atomic_rcu_read(&vq->vring.caches); + caches =3D vring_get_region_caches(vq); pa =3D offsetof(VRingUsed, ring[vq->vring.num]); virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val); address_space_cache_invalidate(&caches->used, pa, sizeof(val)); @@ -577,7 +582,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned = int *in_bytes, total_bufs =3D in_total =3D out_total =3D 0; =20 max =3D vq->vring.num; - caches =3D atomic_rcu_read(&vq->vring.caches); + caches =3D vring_get_region_caches(vq); if (caches->desc.len < max * sizeof(VRingDesc)) { virtio_error(vdev, "Cannot map descriptor ring"); goto err; @@ -844,7 +849,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) =20 i =3D head; =20 - caches =3D atomic_rcu_read(&vq->vring.caches); + caches =3D vring_get_region_caches(vq); if (caches->desc.len < max * sizeof(VRingDesc)) { virtio_error(vdev, "Cannot map descriptor ring"); goto done; @@ -1143,6 +1148,17 @@ static enum virtio_device_endian virtio_current_cpu_= endian(void) } } =20 +static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq) +{ + VRingMemoryRegionCaches *caches; + + caches =3D atomic_read(&vq->vring.caches); + atomic_rcu_set(&vq->vring.caches, NULL); + if (caches) { + call_rcu(caches, virtio_free_region_cache, rcu); + } +} + void virtio_reset(void *opaque) { VirtIODevice *vdev =3D opaque; @@ -1183,6 +1199,7 @@ void virtio_reset(void *opaque) vdev->vq[i].notification =3D true; vdev->vq[i].vring.num =3D vdev->vq[i].vring.num_default; vdev->vq[i].inuse =3D 0; + virtio_virtqueue_reset_region_cache(&vdev->vq[i]); } } =20 @@ -2477,13 +2494,10 @@ static void virtio_device_free_virtqueues(VirtIODev= ice *vdev) } =20 for (i =3D 0; i < VIRTIO_QUEUE_MAX; i++) { - VRingMemoryRegionCaches *caches; if (vdev->vq[i].vring.num =3D=3D 0) { break; } - caches =3D atomic_read(&vdev->vq[i].vring.caches); - atomic_set(&vdev->vq[i].vring.caches, NULL); - virtio_free_region_cache(caches); + virtio_virtqueue_reset_region_cache(&vdev->vq[i]); } g_free(vdev->vq); } --=20 2.7.4