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, 47 insertions, 0 deletions

diff --git a/include/sound/ump_convert.h b/include/sound/ump_convert.h
new file mode 100644
index 000000000..682499b87
--- /dev/null
+++ b/include/sound/ump_convert.h
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef __SOUND_UMP_CONVERT_H
+#define __SOUND_UMP_CONVERT_H
+
+#include <sound/ump_msg.h>
+
+/* context for converting from legacy control messages to UMP packet */
+struct ump_cvt_to_ump_bank {
+	bool rpn_set;
+	bool nrpn_set;
+	bool bank_set;
+	unsigned char cc_rpn_msb, cc_rpn_lsb;
+	unsigned char cc_nrpn_msb, cc_nrpn_lsb;
+	unsigned char cc_data_msb, cc_data_lsb;
+	unsigned char cc_bank_msb, cc_bank_lsb;
+	bool cc_data_msb_set, cc_data_lsb_set;
+};
+
+/* context for converting from MIDI1 byte stream to UMP packet */
+struct ump_cvt_to_ump {
+	/* MIDI1 intermediate buffer */
+	unsigned char buf[6]; /* up to 6 bytes for SysEx */
+	int len;
+	int cmd_bytes;
+
+	/* UMP output packet */
+	u32 ump[4];
+	int ump_bytes;
+
+	/* various status */
+	unsigned int in_sysex;
+	struct ump_cvt_to_ump_bank bank[16];	/* per channel */
+};
+
+int snd_ump_convert_from_ump(const u32 *data, unsigned char *dst,
+			     unsigned char *group_ret);
+void snd_ump_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
+			    unsigned int protocol, unsigned char c);
+
+/* reset the converter context, called at each open to ump */
+static inline void snd_ump_convert_reset(struct ump_cvt_to_ump *ctx)
+{
+	memset(ctx, 0, sizeof(*ctx));
+
+}
+
+#endif /* __SOUND_UMP_CONVERT_H */