KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/sound/soc/sof/stream-ipc.c b/sound/soc/sof/stream-ipc.c
new file mode 100644
index 000000000..78758cf58
--- /dev/null
+++ b/sound/soc/sof/stream-ipc.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2019 Intel Corporation
+//
+// Authors: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
+
+/* Generic SOF IPC code */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <sound/pcm.h>
+#include <sound/sof/stream.h>
+
+#include "ops.h"
+#include "sof-priv.h"
+#include "sof-audio.h"
+
+struct sof_stream {
+	size_t posn_offset;
+};
+
+/* Mailbox-based Generic IPC implementation */
+int sof_ipc_msg_data(struct snd_sof_dev *sdev,
+		     struct snd_sof_pcm_stream *sps,
+		     void *p, size_t sz)
+{
+	if (!sps || !sdev->stream_box.size) {
+		snd_sof_dsp_mailbox_read(sdev, sdev->dsp_box.offset, p, sz);
+	} else {
+		size_t posn_offset;
+
+		if (sps->substream) {
+			struct sof_stream *stream = sps->substream->runtime->private_data;
+
+			/* The stream might already be closed */
+			if (!stream)
+				return -ESTRPIPE;
+
+			posn_offset = stream->posn_offset;
+		} else if (sps->cstream) {
+
+			struct sof_compr_stream *sstream = sps->cstream->runtime->private_data;
+
+			if (!sstream)
+				return -ESTRPIPE;
+
+			posn_offset = sstream->posn_offset;
+
+		} else {
+			dev_err(sdev->dev, "%s: No stream opened\n", __func__);
+			return -EINVAL;
+		}
+
+		snd_sof_dsp_mailbox_read(sdev, posn_offset, p, sz);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_ipc_msg_data);
+
+int sof_set_stream_data_offset(struct snd_sof_dev *sdev,
+			       struct snd_sof_pcm_stream *sps,
+			       size_t posn_offset)
+{
+	/* check if offset is overflow or it is not aligned */
+	if (posn_offset > sdev->stream_box.size ||
+	    posn_offset % sizeof(struct sof_ipc_stream_posn) != 0)
+		return -EINVAL;
+
+	posn_offset += sdev->stream_box.offset;
+
+	if (sps->substream) {
+		struct sof_stream *stream = sps->substream->runtime->private_data;
+
+		stream->posn_offset = posn_offset;
+		dev_dbg(sdev->dev, "pcm: stream dir %d, posn mailbox offset is %zu",
+			sps->substream->stream, posn_offset);
+	} else if (sps->cstream) {
+		struct sof_compr_stream *sstream = sps->cstream->runtime->private_data;
+
+		sstream->posn_offset = posn_offset;
+		dev_dbg(sdev->dev, "compr: stream dir %d, posn mailbox offset is %zu",
+			sps->cstream->direction, posn_offset);
+	} else {
+		dev_err(sdev->dev, "No stream opened");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_set_stream_data_offset);
+
+int sof_stream_pcm_open(struct snd_sof_dev *sdev,
+			struct snd_pcm_substream *substream)
+{
+	struct sof_stream *stream = kmalloc_obj(*stream);
+
+	if (!stream)
+		return -ENOMEM;
+
+	/* binding pcm substream to hda stream */
+	substream->runtime->private_data = stream;
+
+	/* align to DMA minimum transfer size */
+	snd_pcm_hw_constraint_step(substream->runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
+
+	/* avoid circular buffer wrap in middle of period */
+	snd_pcm_hw_constraint_integer(substream->runtime,
+				      SNDRV_PCM_HW_PARAM_PERIODS);
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_stream_pcm_open);
+
+int sof_stream_pcm_close(struct snd_sof_dev *sdev,
+			 struct snd_pcm_substream *substream)
+{
+	struct sof_stream *stream = substream->runtime->private_data;
+
+	substream->runtime->private_data = NULL;
+	kfree(stream);
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_stream_pcm_close);