git: 37b52f666115 - stable/13 - bhyve: Drop volatile qualifiers from virtio rings

The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=37b52f666115cc24e9bc5165d2d17be0338c3b8b

commit 37b52f666115cc24e9bc5165d2d17be0338c3b8b
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-11-11 15:02:10 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-11-29 17:40:13 +0000

    bhyve: Drop volatile qualifiers from virtio rings
    
    The qualifiers are there presumably because these rings are mapped into
    the guest, but they do not appear to be required for correctness, and
    bhyve generally doesn't qualify accesses to guest memory this way.
    Moreover, the qualifiers are discarded by snapshot code, causing clang
    to emit warnings.  Just stop using volatile here.
    
    MFC after:      2 weeks
    Reviewed by:    corvink, jhb
    Differential Revision:  https://reviews.freebsd.org/D37291
    
    (cherry picked from commit 593200c23b57ea6977bf5084b91fc5c63dacbb80)
---
 usr.sbin/bhyve/virtio.c | 13 ++++++-------
 usr.sbin/bhyve/virtio.h |  8 ++++----
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/usr.sbin/bhyve/virtio.c b/usr.sbin/bhyve/virtio.c
index a63e85e6692f..b55b36bb5978 100644
--- a/usr.sbin/bhyve/virtio.c
+++ b/usr.sbin/bhyve/virtio.c
@@ -214,10 +214,9 @@ vi_vq_init(struct virtio_softc *vs, uint32_t pfn)
  * descriptor.
  */
 static inline void
-_vq_record(int i, volatile struct vring_desc *vd,
-	   struct vmctx *ctx, struct iovec *iov, int n_iov,
-	   struct vi_req *reqp) {
-
+_vq_record(int i, struct vring_desc *vd, struct vmctx *ctx, struct iovec *iov,
+    int n_iov, struct vi_req *reqp)
+{
 	if (i >= n_iov)
 		return;
 	iov[i].iov_base = paddr_guest2host(ctx, vd->addr, vd->len);
@@ -271,7 +270,7 @@ vq_getchain(struct vqueue_info *vq, struct iovec *iov, int niov,
 	u_int ndesc, n_indir;
 	u_int idx, next;
 	struct vi_req req;
-	volatile struct vring_desc *vdir, *vindir, *vp;
+	struct vring_desc *vdir, *vindir, *vp;
 	struct vmctx *ctx;
 	struct virtio_softc *vs;
 	const char *name;
@@ -409,8 +408,8 @@ vq_retchains(struct vqueue_info *vq, uint16_t n_chains)
 void
 vq_relchain_prepare(struct vqueue_info *vq, uint16_t idx, uint32_t iolen)
 {
-	volatile struct vring_used *vuh;
-	volatile struct vring_used_elem *vue;
+	struct vring_used *vuh;
+	struct vring_used_elem *vue;
 	uint16_t mask;
 
 	/*
diff --git a/usr.sbin/bhyve/virtio.h b/usr.sbin/bhyve/virtio.h
index a14765e49764..51c57da8c46d 100644
--- a/usr.sbin/bhyve/virtio.h
+++ b/usr.sbin/bhyve/virtio.h
@@ -298,14 +298,14 @@ struct vqueue_info {
 
 	uint32_t vq_pfn;	/* PFN of virt queue (not shifted!) */
 
-	volatile struct vring_desc *vq_desc;	/* descriptor array */
-	volatile struct vring_avail *vq_avail;	/* the "avail" ring */
-	volatile struct vring_used *vq_used;	/* the "used" ring */
+	struct vring_desc *vq_desc;	/* descriptor array */
+	struct vring_avail *vq_avail;	/* the "avail" ring */
+	struct vring_used *vq_used;	/* the "used" ring */
 
 };
 /* as noted above, these are sort of backwards, name-wise */
 #define VQ_AVAIL_EVENT_IDX(vq) \
-	(*(volatile uint16_t *)&(vq)->vq_used->ring[(vq)->vq_qsize])
+	(*(uint16_t *)&(vq)->vq_used->ring[(vq)->vq_qsize])
 #define VQ_USED_EVENT_IDX(vq) \
 	((vq)->vq_avail->ring[(vq)->vq_qsize])