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, 127 insertions, 0 deletions

diff --git a/sound/soc/sof/iomem-utils.c b/sound/soc/sof/iomem-utils.c
new file mode 100644
index 000000000..f6cb79082
--- /dev/null
+++ b/sound/soc/sof/iomem-utils.c
@@ -0,0 +1,127 @@
+// 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) 2018-2022 Intel Corporation
+//
+// Author: Keyon Jie <yang.jie@linux.intel.com>
+//
+
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/platform_device.h>
+#include <linux/unaligned.h>
+#include <sound/soc.h>
+#include <sound/sof.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+/*
+ * Register IO
+ *
+ * The sof_io_xyz() wrappers are typically referenced in snd_sof_dsp_ops
+ * structures and cannot be inlined.
+ */
+
+void sof_io_write(struct snd_sof_dev *sdev, void __iomem *addr, u32 value)
+{
+	writel(value, addr);
+}
+EXPORT_SYMBOL(sof_io_write);
+
+u32 sof_io_read(struct snd_sof_dev *sdev, void __iomem *addr)
+{
+	return readl(addr);
+}
+EXPORT_SYMBOL(sof_io_read);
+
+void sof_io_write64(struct snd_sof_dev *sdev, void __iomem *addr, u64 value)
+{
+	writeq(value, addr);
+}
+EXPORT_SYMBOL(sof_io_write64);
+
+u64 sof_io_read64(struct snd_sof_dev *sdev, void __iomem *addr)
+{
+	return readq(addr);
+}
+EXPORT_SYMBOL(sof_io_read64);
+
+/*
+ * IPC Mailbox IO
+ */
+
+void sof_mailbox_write(struct snd_sof_dev *sdev, u32 offset,
+		       void *message, size_t bytes)
+{
+	void __iomem *dest = sdev->bar[sdev->mailbox_bar] + offset;
+
+	memcpy_toio(dest, message, bytes);
+}
+EXPORT_SYMBOL(sof_mailbox_write);
+
+void sof_mailbox_read(struct snd_sof_dev *sdev, u32 offset,
+		      void *message, size_t bytes)
+{
+	void __iomem *src = sdev->bar[sdev->mailbox_bar] + offset;
+
+	memcpy_fromio(message, src, bytes);
+}
+EXPORT_SYMBOL(sof_mailbox_read);
+
+/*
+ * Memory copy.
+ */
+
+int sof_block_write(struct snd_sof_dev *sdev, enum snd_sof_fw_blk_type blk_type,
+		    u32 offset, void *src, size_t size)
+{
+	int bar = snd_sof_dsp_get_bar_index(sdev, blk_type);
+	const u8 *src_byte = src;
+	void __iomem *dest;
+	u32 affected_mask;
+	u32 tmp;
+	int m, n;
+
+	if (bar < 0)
+		return bar;
+
+	dest = sdev->bar[bar] + offset;
+
+	m = size / 4;
+	n = size % 4;
+
+	/* __iowrite32_copy use 32bit size values so divide by 4 */
+	__iowrite32_copy(dest, src, m);
+
+	if (n) {
+		affected_mask = (1 << (8 * n)) - 1;
+
+		/* first read the 32bit data of dest, then change affected
+		 * bytes, and write back to dest. For unaffected bytes, it
+		 * should not be changed
+		 */
+		tmp = ioread32(dest + m * 4);
+		tmp &= ~affected_mask;
+
+		tmp |= *(u32 *)(src_byte + m * 4) & affected_mask;
+		iowrite32(tmp, dest + m * 4);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_block_write);
+
+int sof_block_read(struct snd_sof_dev *sdev, enum snd_sof_fw_blk_type blk_type,
+		   u32 offset, void *dest, size_t size)
+{
+	int bar = snd_sof_dsp_get_bar_index(sdev, blk_type);
+
+	if (bar < 0)
+		return bar;
+
+	memcpy_fromio(dest, sdev->bar[bar] + offset, size);
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_block_read);