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, 90 insertions, 0 deletions

diff --git a/include/sound/initval.h b/include/sound/initval.h
new file mode 100644
index 000000000..a1ff3b486
--- /dev/null
+++ b/include/sound/initval.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __SOUND_INITVAL_H
+#define __SOUND_INITVAL_H
+
+/*
+ *  Init values for soundcard modules
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ */
+
+#define SNDRV_AUTO_PORT		1
+#define SNDRV_AUTO_IRQ		0xffff
+#define SNDRV_AUTO_DMA		0xffff
+#define SNDRV_AUTO_DMA_SIZE	(0x7fffffff)
+
+#define SNDRV_DEFAULT_IDX1	(-1)
+#define SNDRV_DEFAULT_STR1	NULL
+#define SNDRV_DEFAULT_ENABLE1	1
+#define SNDRV_DEFAULT_PORT1	SNDRV_AUTO_PORT
+#define SNDRV_DEFAULT_IRQ1	SNDRV_AUTO_IRQ
+#define SNDRV_DEFAULT_DMA1	SNDRV_AUTO_DMA
+#define SNDRV_DEFAULT_DMA_SIZE1	SNDRV_AUTO_DMA_SIZE
+#define SNDRV_DEFAULT_PTR1	SNDRV_DEFAULT_STR1
+
+#define SNDRV_DEFAULT_IDX	{ [0 ... (SNDRV_CARDS-1)] = -1 }
+#define SNDRV_DEFAULT_STR	{ [0 ... (SNDRV_CARDS-1)] = NULL }
+#define SNDRV_DEFAULT_ENABLE	{ 1, [1 ... (SNDRV_CARDS-1)] = 0 }
+#define SNDRV_DEFAULT_ENABLE_PNP { [0 ... (SNDRV_CARDS-1)] = 1 }
+#ifdef CONFIG_PNP
+#define SNDRV_DEFAULT_ENABLE_ISAPNP SNDRV_DEFAULT_ENABLE_PNP
+#else
+#define SNDRV_DEFAULT_ENABLE_ISAPNP SNDRV_DEFAULT_ENABLE
+#endif
+#define SNDRV_DEFAULT_PORT	{ [0 ... (SNDRV_CARDS-1)] = SNDRV_AUTO_PORT }
+#define SNDRV_DEFAULT_IRQ	{ [0 ... (SNDRV_CARDS-1)] = SNDRV_AUTO_IRQ }
+#define SNDRV_DEFAULT_DMA	{ [0 ... (SNDRV_CARDS-1)] = SNDRV_AUTO_DMA }
+#define SNDRV_DEFAULT_DMA_SIZE	{ [0 ... (SNDRV_CARDS-1)] = SNDRV_AUTO_DMA_SIZE }
+#define SNDRV_DEFAULT_PTR	SNDRV_DEFAULT_STR
+
+#ifdef SNDRV_LEGACY_FIND_FREE_IOPORT
+static long snd_legacy_find_free_ioport(const long *port_table, long size)
+{
+	while (*port_table != -1) {
+		if (request_region(*port_table, size, "ALSA test")) {
+			release_region(*port_table, size);
+			return *port_table;
+		}
+		port_table++;
+	}
+	return -1;
+}
+#endif
+
+#ifdef SNDRV_LEGACY_FIND_FREE_IRQ
+#include <linux/interrupt.h>
+
+static irqreturn_t snd_legacy_empty_irq_handler(int irq, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
+static int snd_legacy_find_free_irq(const int *irq_table)
+{
+	while (*irq_table != -1) {
+		if (!request_irq(*irq_table, snd_legacy_empty_irq_handler,
+				 IRQF_PROBE_SHARED, "ALSA Test IRQ",
+				 (void *) irq_table)) {
+			free_irq(*irq_table, (void *) irq_table);
+			return *irq_table;
+		}
+		irq_table++;
+	}
+	return -1;
+}
+#endif
+
+#ifdef SNDRV_LEGACY_FIND_FREE_DMA
+static int snd_legacy_find_free_dma(const int *dma_table)
+{
+	while (*dma_table != -1) {
+		if (!request_dma(*dma_table, "ALSA Test DMA")) {
+			free_dma(*dma_table);
+			return *dma_table;
+		}
+		dma_table++;
+	}
+	return -1;
+}
+#endif
+
+#endif /* __SOUND_INITVAL_H */