From: "Jan Beulich" <JBeulich@suse.com> To: qemu-devel@nongnu.org Cc: anthony.perard@citrix.com, Paul Durrant <paul.durrant@citrix.com>, Stefano Stabellini <sstabellini@kernel.org>, xen-devel <xen-devel@lists.xenproject.org> Subject: [Qemu-devel] [PATCH 2/3] xen: slightly simplify bufioreq handling Date: Wed, 23 Nov 2016 02:24:40 -0700 [thread overview] Message-ID: <58356E680200007800121299@prv-mh.provo.novell.com> (raw) In-Reply-To: <58356D610200007800121289@prv-mh.provo.novell.com> There's no point setting fields always receiving the same value on each iteration, as handle_ioreq() doesn't alter them anyway. Set state and count once ahead of the loop, drop the redundant clearing of data_is_ptr, and avoid the meaningless setting of df altogether. Also avoid doing an unsigned long calculation of size when the field to be initialized is only 32 bits wide (and the shift value in the range 0...3). Signed-off-by: Jan Beulich <jbeulich@suse.com> --- a/xen-hvm.c +++ b/xen-hvm.c @@ -995,6 +995,8 @@ static int handle_buffered_iopage(XenIOS } memset(&req, 0x00, sizeof(req)); + req.state = STATE_IOREQ_READY; + req.count = 1; for (;;) { uint32_t rdptr = buf_page->read_pointer, wrptr; @@ -1009,15 +1011,11 @@ static int handle_buffered_iopage(XenIOS break; } buf_req = &buf_page->buf_ioreq[rdptr % IOREQ_BUFFER_SLOT_NUM]; - req.size = 1UL << buf_req->size; - req.count = 1; + req.size = 1U << buf_req->size; req.addr = buf_req->addr; req.data = buf_req->data; - req.state = STATE_IOREQ_READY; req.dir = buf_req->dir; - req.df = 1; req.type = buf_req->type; - req.data_is_ptr = 0; xen_rmb(); qw = (req.size == 8); if (qw) { @@ -1032,6 +1030,13 @@ static int handle_buffered_iopage(XenIOS handle_ioreq(state, &req); + /* Only req.data may get updated by handle_ioreq(), albeit even that + * should not happen as such data would never make it to the guest. + */ + assert(req.state == STATE_IOREQ_READY); + assert(req.count == 1); + assert(!req.data_is_ptr); + atomic_add(&buf_page->read_pointer, qw + 1); }
WARNING: multiple messages have this Message-ID (diff)
From: "Jan Beulich" <JBeulich@suse.com> To: qemu-devel@nongnu.org Cc: anthony.perard@citrix.com, xen-devel <xen-devel@lists.xenproject.org>, Paul Durrant <paul.durrant@citrix.com>, Stefano Stabellini <sstabellini@kernel.org> Subject: [PATCH 2/3] xen: slightly simplify bufioreq handling Date: Wed, 23 Nov 2016 02:24:40 -0700 [thread overview] Message-ID: <58356E680200007800121299@prv-mh.provo.novell.com> (raw) In-Reply-To: <58356D610200007800121289@prv-mh.provo.novell.com> There's no point setting fields always receiving the same value on each iteration, as handle_ioreq() doesn't alter them anyway. Set state and count once ahead of the loop, drop the redundant clearing of data_is_ptr, and avoid the meaningless setting of df altogether. Also avoid doing an unsigned long calculation of size when the field to be initialized is only 32 bits wide (and the shift value in the range 0...3). Signed-off-by: Jan Beulich <jbeulich@suse.com> --- a/xen-hvm.c +++ b/xen-hvm.c @@ -995,6 +995,8 @@ static int handle_buffered_iopage(XenIOS } memset(&req, 0x00, sizeof(req)); + req.state = STATE_IOREQ_READY; + req.count = 1; for (;;) { uint32_t rdptr = buf_page->read_pointer, wrptr; @@ -1009,15 +1011,11 @@ static int handle_buffered_iopage(XenIOS break; } buf_req = &buf_page->buf_ioreq[rdptr % IOREQ_BUFFER_SLOT_NUM]; - req.size = 1UL << buf_req->size; - req.count = 1; + req.size = 1U << buf_req->size; req.addr = buf_req->addr; req.data = buf_req->data; - req.state = STATE_IOREQ_READY; req.dir = buf_req->dir; - req.df = 1; req.type = buf_req->type; - req.data_is_ptr = 0; xen_rmb(); qw = (req.size == 8); if (qw) { @@ -1032,6 +1030,13 @@ static int handle_buffered_iopage(XenIOS handle_ioreq(state, &req); + /* Only req.data may get updated by handle_ioreq(), albeit even that + * should not happen as such data would never make it to the guest. + */ + assert(req.state == STATE_IOREQ_READY); + assert(req.count == 1); + assert(!req.data_is_ptr); + atomic_add(&buf_page->read_pointer, qw + 1); } _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-11-23 9:24 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-11-23 9:20 [Qemu-devel] [PATCH 0/3] xen: XSA-197 follow-ups Jan Beulich 2016-11-23 9:24 ` [PATCH 1/3] xen: fix quad word bufioreq handling Jan Beulich 2016-11-23 9:24 ` [Qemu-devel] " Jan Beulich 2016-11-23 9:48 ` Paul Durrant 2016-11-23 10:36 ` Jan Beulich 2016-11-23 10:36 ` [Qemu-devel] " Jan Beulich 2016-11-23 10:45 ` Paul Durrant 2016-11-23 11:28 ` Jan Beulich 2016-11-23 11:28 ` [Qemu-devel] " Jan Beulich 2016-11-23 18:01 ` Stefano Stabellini 2016-11-23 18:01 ` Stefano Stabellini 2016-11-23 10:45 ` Paul Durrant 2016-11-23 9:48 ` Paul Durrant 2016-11-23 9:24 ` Jan Beulich [this message] 2016-11-23 9:24 ` [PATCH 2/3] xen: slightly simplify " Jan Beulich 2016-11-23 9:51 ` [Qemu-devel] " Paul Durrant 2016-11-23 9:51 ` Paul Durrant 2016-11-23 18:13 ` Stefano Stabellini 2016-11-23 18:13 ` [Qemu-devel] " Stefano Stabellini 2016-11-24 10:31 ` Jan Beulich 2016-11-24 10:31 ` Jan Beulich 2016-11-23 9:25 ` [Qemu-devel] [PATCH 3/3] xen: ignore direction in " Jan Beulich 2016-11-23 9:25 ` Jan Beulich 2016-11-23 9:55 ` [Qemu-devel] " Paul Durrant 2016-11-23 9:55 ` Paul Durrant 2016-11-23 18:16 ` Stefano Stabellini 2016-11-23 18:16 ` [Qemu-devel] " Stefano Stabellini
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