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, 133 insertions, 0 deletions

diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
new file mode 100644
index 000000000..cf5ecae4a
--- /dev/null
+++ b/include/net/phonet/phonet.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * File: af_phonet.h
+ *
+ * Phonet sockets kernel definitions
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ */
+
+#ifndef AF_PHONET_H
+#define AF_PHONET_H
+
+#include <linux/phonet.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+
+/*
+ * The lower layers may not require more space, ever. Make sure it's
+ * enough.
+ */
+#define MAX_PHONET_HEADER	(8 + MAX_HEADER)
+
+/*
+ * Every Phonet* socket has this structure first in its
+ * protocol-specific structure under name c.
+ */
+struct pn_sock {
+	struct sock	sk;
+	u16		sobject;
+	u16		dobject;
+	u8		resource;
+};
+
+static inline struct pn_sock *pn_sk(struct sock *sk)
+{
+	return (struct pn_sock *)sk;
+}
+
+extern const struct proto_ops phonet_dgram_ops;
+
+void pn_sock_init(void);
+struct sock *pn_find_sock_by_sa(struct net *net, const struct sockaddr_pn *sa);
+void pn_deliver_sock_broadcast(struct net *net, struct sk_buff *skb);
+void phonet_get_local_port_range(int *min, int *max);
+int pn_sock_hash(struct sock *sk);
+void pn_sock_unhash(struct sock *sk);
+int pn_sock_get_port(struct sock *sk, unsigned short sport);
+
+struct sock *pn_find_sock_by_res(struct net *net, u8 res);
+int pn_sock_bind_res(struct sock *sock, u8 res);
+int pn_sock_unbind_res(struct sock *sk, u8 res);
+void pn_sock_unbind_all_res(struct sock *sk);
+
+int pn_skb_send(struct sock *sk, struct sk_buff *skb,
+		const struct sockaddr_pn *target);
+
+static inline struct phonethdr *pn_hdr(struct sk_buff *skb)
+{
+	return (struct phonethdr *)skb_network_header(skb);
+}
+
+static inline struct phonetmsg *pn_msg(struct sk_buff *skb)
+{
+	return (struct phonetmsg *)skb_transport_header(skb);
+}
+
+/*
+ * Get the other party's sockaddr from received skb. The skb begins
+ * with a Phonet header.
+ */
+static inline
+void pn_skb_get_src_sockaddr(struct sk_buff *skb, struct sockaddr_pn *sa)
+{
+	struct phonethdr *ph = pn_hdr(skb);
+	u16 obj = pn_object(ph->pn_sdev, ph->pn_sobj);
+
+	sa->spn_family = AF_PHONET;
+	pn_sockaddr_set_object(sa, obj);
+	pn_sockaddr_set_resource(sa, ph->pn_res);
+	memset(sa->spn_zero, 0, sizeof(sa->spn_zero));
+}
+
+static inline
+void pn_skb_get_dst_sockaddr(struct sk_buff *skb, struct sockaddr_pn *sa)
+{
+	struct phonethdr *ph = pn_hdr(skb);
+	u16 obj = pn_object(ph->pn_rdev, ph->pn_robj);
+
+	sa->spn_family = AF_PHONET;
+	pn_sockaddr_set_object(sa, obj);
+	pn_sockaddr_set_resource(sa, ph->pn_res);
+	memset(sa->spn_zero, 0, sizeof(sa->spn_zero));
+}
+
+/* Protocols in Phonet protocol family. */
+struct phonet_protocol {
+	const struct proto_ops	*ops;
+	struct proto		*prot;
+	int			sock_type;
+};
+
+int phonet_proto_register(unsigned int protocol,
+		const struct phonet_protocol *pp);
+void phonet_proto_unregister(unsigned int protocol,
+		const struct phonet_protocol *pp);
+
+int phonet_sysctl_init(void);
+void phonet_sysctl_exit(void);
+int isi_register(void);
+void isi_unregister(void);
+
+static inline bool sk_is_phonet(struct sock *sk)
+{
+	return sk->sk_family == PF_PHONET;
+}
+
+static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd,
+				  void __user *arg)
+{
+	int karg;
+
+	switch (cmd) {
+	case SIOCPNADDRESOURCE:
+	case SIOCPNDELRESOURCE:
+		if (get_user(karg, (int __user *)arg))
+			return -EFAULT;
+
+		return sk->sk_prot->ioctl(sk, cmd, &karg);
+	}
+	/* A positive return value means that the ioctl was not processed */
+	return 1;
+}
+#endif