2019-08-12 15:09:05 +08:00
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Gao Junhao <junhao.gao@intel.com>
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Date: Thu, 30 May 2019 11:22:02 +0000
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Subject: [PATCH] vbs: set memory barrier for virtio_vq
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When virtio backend driver gets avail_idx or sets used_idx, memory
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barrier can make sure of sequence of reading and writing. It can
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guarantee the accuracy of avail_idx and used_idx.
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Change-Id: I4eb4a34395c215d297b24fb993dbedccfa5d95ce
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Tracked-On: projectacrn/acrn-hypervisor#3207
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Signed-off-by: Gao Junhao <junhao.gao@intel.com>
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Reviewed-by: Yu Wang <yu1.wang@intel.com>
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Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
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---
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drivers/vbs/vq.c | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/drivers/vbs/vq.c b/drivers/vbs/vq.c
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2020-05-05 09:02:46 +08:00
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index 3a714441f..180d1b223 100644
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2019-08-12 15:09:05 +08:00
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--- a/drivers/vbs/vq.c
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+++ b/drivers/vbs/vq.c
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@@ -145,6 +145,7 @@ int virtio_vq_getchain(struct virtio_vq_info *vq, uint16_t *pidx,
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dev = vq->dev;
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name = dev->name;
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+ rmb();
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/*
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* Note: it's the responsibility of the guest not to
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* update vq->vq_avail->va_idx until all of the descriptors
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@@ -288,6 +289,8 @@ void virtio_vq_relchain(struct virtio_vq_info *vq, uint16_t idx,
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vue = &vuh->ring[uidx++ & mask];
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vue->id = idx;
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vue->len = iolen;
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+ /* Make sure buffer is written before we update index. */
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+ wmb();
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vuh->idx = uidx;
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}
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EXPORT_SYMBOL(virtio_vq_relchain);
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@@ -322,6 +325,7 @@ void virtio_vq_endchains(struct virtio_vq_info *vq, int used_all_avail)
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* In any case, though, if NOTIFY_ON_EMPTY is set and the
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* entire avail was processed, we need to interrupt always.
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*/
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+ mb();
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dev = vq->dev;
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old_idx = vq->save_used;
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vq->save_used = new_idx = vq->used->idx;
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--
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https://clearlinux.org
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