Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 660 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/guest-state-buffer.c b/arch/powerpc/kvm/guest-state-buffer.c
new file mode 100644
index 000000000..42843eca6
--- /dev/null
+++ b/arch/powerpc/kvm/guest-state-buffer.c
@@ -0,0 +1,660 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "asm/hvcall.h"
+#include <linux/log2.h>
+#include <asm/pgalloc.h>
+#include <asm/guest-state-buffer.h>
+
+static const u16 kvmppc_gse_iden_len[__KVMPPC_GSE_TYPE_MAX] = {
+	[KVMPPC_GSE_BE32] = sizeof(__be32),
+	[KVMPPC_GSE_BE64] = sizeof(__be64),
+	[KVMPPC_GSE_VEC128] = sizeof(vector128),
+	[KVMPPC_GSE_PARTITION_TABLE] = sizeof(struct kvmppc_gs_part_table),
+	[KVMPPC_GSE_PROCESS_TABLE] = sizeof(struct kvmppc_gs_proc_table),
+	[KVMPPC_GSE_BUFFER] = sizeof(struct kvmppc_gs_buff_info),
+};
+
+/**
+ * kvmppc_gsb_new() - create a new guest state buffer
+ * @size: total size of the guest state buffer (includes header)
+ * @guest_id: guest_id
+ * @vcpu_id: vcpu_id
+ * @flags: GFP flags
+ *
+ * Returns a guest state buffer.
+ */
+struct kvmppc_gs_buff *kvmppc_gsb_new(size_t size, unsigned long guest_id,
+				      unsigned long vcpu_id, gfp_t flags)
+{
+	struct kvmppc_gs_buff *gsb;
+
+	gsb = kzalloc_obj(*gsb, flags);
+	if (!gsb)
+		return NULL;
+
+	size = roundup_pow_of_two(size);
+	gsb->hdr = kzalloc(size, GFP_KERNEL);
+	if (!gsb->hdr)
+		goto free;
+
+	gsb->capacity = size;
+	gsb->len = sizeof(struct kvmppc_gs_header);
+	gsb->vcpu_id = vcpu_id;
+	gsb->guest_id = guest_id;
+
+	gsb->hdr->nelems = cpu_to_be32(0);
+
+	return gsb;
+
+free:
+	kfree(gsb);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsb_new);
+
+/**
+ * kvmppc_gsb_free() - free a guest state buffer
+ * @gsb: guest state buffer
+ */
+void kvmppc_gsb_free(struct kvmppc_gs_buff *gsb)
+{
+	kfree(gsb->hdr);
+	kfree(gsb);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsb_free);
+
+/**
+ * kvmppc_gsb_put() - allocate space in a guest state buffer
+ * @gsb: buffer to allocate in
+ * @size: amount of space to allocate
+ *
+ * Returns a pointer to the amount of space requested within the buffer and
+ * increments the count of elements in the buffer.
+ *
+ * Does not check if there is enough space in the buffer.
+ */
+void *kvmppc_gsb_put(struct kvmppc_gs_buff *gsb, size_t size)
+{
+	u32 nelems = kvmppc_gsb_nelems(gsb);
+	void *p;
+
+	p = (void *)kvmppc_gsb_header(gsb) + kvmppc_gsb_len(gsb);
+	gsb->len += size;
+
+	kvmppc_gsb_header(gsb)->nelems = cpu_to_be32(nelems + 1);
+	return p;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsb_put);
+
+static int kvmppc_gsid_class(u16 iden)
+{
+	if ((iden >= KVMPPC_GSE_GUESTWIDE_START) &&
+	    (iden <= KVMPPC_GSE_GUESTWIDE_END))
+		return KVMPPC_GS_CLASS_GUESTWIDE;
+
+	if ((iden >= KVMPPC_GSE_HOSTWIDE_START) &&
+	    (iden <= KVMPPC_GSE_HOSTWIDE_END))
+		return KVMPPC_GS_CLASS_HOSTWIDE;
+
+	if ((iden >= KVMPPC_GSE_META_START) && (iden <= KVMPPC_GSE_META_END))
+		return KVMPPC_GS_CLASS_META;
+
+	if ((iden >= KVMPPC_GSE_DW_REGS_START) &&
+	    (iden <= KVMPPC_GSE_DW_REGS_END))
+		return KVMPPC_GS_CLASS_DWORD_REG;
+
+	if ((iden >= KVMPPC_GSE_W_REGS_START) &&
+	    (iden <= KVMPPC_GSE_W_REGS_END))
+		return KVMPPC_GS_CLASS_WORD_REG;
+
+	if ((iden >= KVMPPC_GSE_VSRS_START) && (iden <= KVMPPC_GSE_VSRS_END))
+		return KVMPPC_GS_CLASS_VECTOR;
+
+	if ((iden >= KVMPPC_GSE_INTR_REGS_START) &&
+	    (iden <= KVMPPC_GSE_INTR_REGS_END))
+		return KVMPPC_GS_CLASS_INTR;
+
+	return -1;
+}
+
+static int kvmppc_gsid_type(u16 iden)
+{
+	int type = -1;
+
+	switch (kvmppc_gsid_class(iden)) {
+	case KVMPPC_GS_CLASS_HOSTWIDE:
+		switch (iden) {
+		case KVMPPC_GSID_L0_GUEST_HEAP:
+			fallthrough;
+		case KVMPPC_GSID_L0_GUEST_HEAP_MAX:
+			fallthrough;
+		case KVMPPC_GSID_L0_GUEST_PGTABLE_SIZE:
+			fallthrough;
+		case KVMPPC_GSID_L0_GUEST_PGTABLE_SIZE_MAX:
+			fallthrough;
+		case KVMPPC_GSID_L0_GUEST_PGTABLE_RECLAIM:
+			type = KVMPPC_GSE_BE64;
+			break;
+		}
+		break;
+	case KVMPPC_GS_CLASS_GUESTWIDE:
+		switch (iden) {
+		case KVMPPC_GSID_HOST_STATE_SIZE:
+		case KVMPPC_GSID_RUN_OUTPUT_MIN_SIZE:
+		case KVMPPC_GSID_TB_OFFSET:
+			type = KVMPPC_GSE_BE64;
+			break;
+		case KVMPPC_GSID_PARTITION_TABLE:
+			type = KVMPPC_GSE_PARTITION_TABLE;
+			break;
+		case KVMPPC_GSID_PROCESS_TABLE:
+			type = KVMPPC_GSE_PROCESS_TABLE;
+			break;
+		case KVMPPC_GSID_LOGICAL_PVR:
+			type = KVMPPC_GSE_BE32;
+			break;
+		}
+		break;
+	case KVMPPC_GS_CLASS_META:
+		switch (iden) {
+		case KVMPPC_GSID_RUN_INPUT:
+		case KVMPPC_GSID_RUN_OUTPUT:
+			type = KVMPPC_GSE_BUFFER;
+			break;
+		case KVMPPC_GSID_VPA:
+			type = KVMPPC_GSE_BE64;
+			break;
+		}
+		break;
+	case KVMPPC_GS_CLASS_DWORD_REG:
+		type = KVMPPC_GSE_BE64;
+		break;
+	case KVMPPC_GS_CLASS_WORD_REG:
+		type = KVMPPC_GSE_BE32;
+		break;
+	case KVMPPC_GS_CLASS_VECTOR:
+		type = KVMPPC_GSE_VEC128;
+		break;
+	case KVMPPC_GS_CLASS_INTR:
+		switch (iden) {
+		case KVMPPC_GSID_HDAR:
+		case KVMPPC_GSID_ASDR:
+		case KVMPPC_GSID_HEIR:
+			type = KVMPPC_GSE_BE64;
+			break;
+		case KVMPPC_GSID_HDSISR:
+			type = KVMPPC_GSE_BE32;
+			break;
+		}
+		break;
+	}
+
+	return type;
+}
+
+/**
+ * kvmppc_gsid_flags() - the flags for a guest state ID
+ * @iden: guest state ID
+ *
+ * Returns any flags for the guest state ID.
+ */
+unsigned long kvmppc_gsid_flags(u16 iden)
+{
+	unsigned long flags = 0;
+
+	switch (kvmppc_gsid_class(iden)) {
+	case KVMPPC_GS_CLASS_GUESTWIDE:
+		flags = KVMPPC_GS_FLAGS_WIDE;
+		break;
+	case KVMPPC_GS_CLASS_HOSTWIDE:
+		flags = KVMPPC_GS_FLAGS_HOST_WIDE;
+		break;
+	case KVMPPC_GS_CLASS_META:
+	case KVMPPC_GS_CLASS_DWORD_REG:
+	case KVMPPC_GS_CLASS_WORD_REG:
+	case KVMPPC_GS_CLASS_VECTOR:
+	case KVMPPC_GS_CLASS_INTR:
+		break;
+	}
+
+	return flags;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsid_flags);
+
+/**
+ * kvmppc_gsid_size() - the size of a guest state ID
+ * @iden: guest state ID
+ *
+ * Returns the size of guest state ID.
+ */
+u16 kvmppc_gsid_size(u16 iden)
+{
+	int type;
+
+	type = kvmppc_gsid_type(iden);
+	if (type == -1)
+		return 0;
+
+	if (type >= __KVMPPC_GSE_TYPE_MAX)
+		return 0;
+
+	return kvmppc_gse_iden_len[type];
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsid_size);
+
+/**
+ * kvmppc_gsid_mask() - the settable bits of a guest state ID
+ * @iden: guest state ID
+ *
+ * Returns a mask of settable bits for a guest state ID.
+ */
+u64 kvmppc_gsid_mask(u16 iden)
+{
+	u64 mask = ~0ull;
+
+	switch (iden) {
+	case KVMPPC_GSID_LPCR:
+		mask = LPCR_DPFD | LPCR_ILE | LPCR_AIL | LPCR_LD | LPCR_MER |
+		       LPCR_GTSE;
+		break;
+	case KVMPPC_GSID_MSR:
+		mask = ~(MSR_HV | MSR_S | MSR_ME);
+		break;
+	}
+
+	return mask;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsid_mask);
+
+/**
+ * __kvmppc_gse_put() - add a guest state element to a buffer
+ * @gsb: buffer to the element to
+ * @iden: guest state ID
+ * @size: length of data
+ * @data: pointer to data
+ */
+int __kvmppc_gse_put(struct kvmppc_gs_buff *gsb, u16 iden, u16 size,
+		     const void *data)
+{
+	struct kvmppc_gs_elem *gse;
+	u16 total_size;
+
+	total_size = sizeof(*gse) + size;
+	if (total_size + kvmppc_gsb_len(gsb) > kvmppc_gsb_capacity(gsb))
+		return -ENOMEM;
+
+	if (kvmppc_gsid_size(iden) != size)
+		return -EINVAL;
+
+	gse = kvmppc_gsb_put(gsb, total_size);
+	gse->iden = cpu_to_be16(iden);
+	gse->len = cpu_to_be16(size);
+	memcpy(gse->data, data, size);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__kvmppc_gse_put);
+
+/**
+ * kvmppc_gse_parse() - create a parse map from a guest state buffer
+ * @gsp: guest state parser
+ * @gsb: guest state buffer
+ */
+int kvmppc_gse_parse(struct kvmppc_gs_parser *gsp, struct kvmppc_gs_buff *gsb)
+{
+	struct kvmppc_gs_elem *curr;
+	int rem, i;
+
+	kvmppc_gsb_for_each_elem(i, curr, gsb, rem) {
+		if (kvmppc_gse_len(curr) !=
+		    kvmppc_gsid_size(kvmppc_gse_iden(curr)))
+			return -EINVAL;
+		kvmppc_gsp_insert(gsp, kvmppc_gse_iden(curr), curr);
+	}
+
+	if (kvmppc_gsb_nelems(gsb) != i)
+		return -EINVAL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gse_parse);
+
+static inline int kvmppc_gse_flatten_iden(u16 iden)
+{
+	int bit = 0;
+	int class;
+
+	class = kvmppc_gsid_class(iden);
+
+	if (class == KVMPPC_GS_CLASS_GUESTWIDE) {
+		bit += iden - KVMPPC_GSE_GUESTWIDE_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_GUESTWIDE_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_HOSTWIDE) {
+		bit += iden - KVMPPC_GSE_HOSTWIDE_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_HOSTWIDE_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_META) {
+		bit += iden - KVMPPC_GSE_META_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_META_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_DWORD_REG) {
+		bit += iden - KVMPPC_GSE_DW_REGS_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_DW_REGS_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_WORD_REG) {
+		bit += iden - KVMPPC_GSE_W_REGS_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_W_REGS_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_VECTOR) {
+		bit += iden - KVMPPC_GSE_VSRS_START;
+		return bit;
+	}
+
+	bit += KVMPPC_GSE_VSRS_COUNT;
+
+	if (class == KVMPPC_GS_CLASS_INTR) {
+		bit += iden - KVMPPC_GSE_INTR_REGS_START;
+		return bit;
+	}
+
+	return 0;
+}
+
+static inline u16 kvmppc_gse_unflatten_iden(int bit)
+{
+	u16 iden;
+
+	if (bit < KVMPPC_GSE_GUESTWIDE_COUNT) {
+		iden = KVMPPC_GSE_GUESTWIDE_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_GUESTWIDE_COUNT;
+
+	if (bit < KVMPPC_GSE_HOSTWIDE_COUNT) {
+		iden = KVMPPC_GSE_HOSTWIDE_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_HOSTWIDE_COUNT;
+
+	if (bit < KVMPPC_GSE_META_COUNT) {
+		iden = KVMPPC_GSE_META_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_META_COUNT;
+
+	if (bit < KVMPPC_GSE_DW_REGS_COUNT) {
+		iden = KVMPPC_GSE_DW_REGS_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_DW_REGS_COUNT;
+
+	if (bit < KVMPPC_GSE_W_REGS_COUNT) {
+		iden = KVMPPC_GSE_W_REGS_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_W_REGS_COUNT;
+
+	if (bit < KVMPPC_GSE_VSRS_COUNT) {
+		iden = KVMPPC_GSE_VSRS_START + bit;
+		return iden;
+	}
+	bit -= KVMPPC_GSE_VSRS_COUNT;
+
+	if (bit < KVMPPC_GSE_IDEN_COUNT) {
+		iden = KVMPPC_GSE_INTR_REGS_START + bit;
+		return iden;
+	}
+
+	return 0;
+}
+
+/**
+ * kvmppc_gsp_insert() - add a mapping from an guest state ID to an element
+ * @gsp: guest state parser
+ * @iden: guest state id (key)
+ * @gse: guest state element (value)
+ */
+void kvmppc_gsp_insert(struct kvmppc_gs_parser *gsp, u16 iden,
+		       struct kvmppc_gs_elem *gse)
+{
+	int i;
+
+	i = kvmppc_gse_flatten_iden(iden);
+	kvmppc_gsbm_set(&gsp->iterator, iden);
+	gsp->gses[i] = gse;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsp_insert);
+
+/**
+ * kvmppc_gsp_lookup() - lookup an element from a guest state ID
+ * @gsp: guest state parser
+ * @iden: guest state ID (key)
+ *
+ * Returns the guest state element if present.
+ */
+struct kvmppc_gs_elem *kvmppc_gsp_lookup(struct kvmppc_gs_parser *gsp, u16 iden)
+{
+	int i;
+
+	i = kvmppc_gse_flatten_iden(iden);
+	return gsp->gses[i];
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsp_lookup);
+
+/**
+ * kvmppc_gsbm_set() - set the guest state ID
+ * @gsbm: guest state bitmap
+ * @iden: guest state ID
+ */
+void kvmppc_gsbm_set(struct kvmppc_gs_bitmap *gsbm, u16 iden)
+{
+	set_bit(kvmppc_gse_flatten_iden(iden), gsbm->bitmap);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsbm_set);
+
+/**
+ * kvmppc_gsbm_clear() - clear the guest state ID
+ * @gsbm: guest state bitmap
+ * @iden: guest state ID
+ */
+void kvmppc_gsbm_clear(struct kvmppc_gs_bitmap *gsbm, u16 iden)
+{
+	clear_bit(kvmppc_gse_flatten_iden(iden), gsbm->bitmap);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsbm_clear);
+
+/**
+ * kvmppc_gsbm_test() - test the guest state ID
+ * @gsbm: guest state bitmap
+ * @iden: guest state ID
+ */
+bool kvmppc_gsbm_test(struct kvmppc_gs_bitmap *gsbm, u16 iden)
+{
+	return test_bit(kvmppc_gse_flatten_iden(iden), gsbm->bitmap);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsbm_test);
+
+/**
+ * kvmppc_gsbm_next() - return the next set guest state ID
+ * @gsbm: guest state bitmap
+ * @prev: last guest state ID
+ */
+u16 kvmppc_gsbm_next(struct kvmppc_gs_bitmap *gsbm, u16 prev)
+{
+	int bit, pbit;
+
+	pbit = prev ? kvmppc_gse_flatten_iden(prev) + 1 : 0;
+	bit = find_next_bit(gsbm->bitmap, KVMPPC_GSE_IDEN_COUNT, pbit);
+
+	if (bit < KVMPPC_GSE_IDEN_COUNT)
+		return kvmppc_gse_unflatten_iden(bit);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsbm_next);
+
+/**
+ * kvmppc_gsm_init() - initialize a guest state message
+ * @gsm: guest state message
+ * @ops: callbacks
+ * @data: private data
+ * @flags: guest wide or thread wide
+ */
+int kvmppc_gsm_init(struct kvmppc_gs_msg *gsm, struct kvmppc_gs_msg_ops *ops,
+		    void *data, unsigned long flags)
+{
+	memset(gsm, 0, sizeof(*gsm));
+	gsm->ops = ops;
+	gsm->data = data;
+	gsm->flags = flags;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_init);
+
+/**
+ * kvmppc_gsm_new() - creates a new guest state message
+ * @ops: callbacks
+ * @data: private data
+ * @flags: guest wide or thread wide
+ * @gfp_flags: GFP allocation flags
+ *
+ * Returns an initialized guest state message.
+ */
+struct kvmppc_gs_msg *kvmppc_gsm_new(struct kvmppc_gs_msg_ops *ops, void *data,
+				     unsigned long flags, gfp_t gfp_flags)
+{
+	struct kvmppc_gs_msg *gsm;
+
+	gsm = kzalloc_obj(*gsm, gfp_flags);
+	if (!gsm)
+		return NULL;
+
+	kvmppc_gsm_init(gsm, ops, data, flags);
+
+	return gsm;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_new);
+
+/**
+ * kvmppc_gsm_size() - creates a new guest state message
+ * @gsm: self
+ *
+ * Returns the size required for the message.
+ */
+size_t kvmppc_gsm_size(struct kvmppc_gs_msg *gsm)
+{
+	if (gsm->ops->get_size)
+		return gsm->ops->get_size(gsm);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_size);
+
+/**
+ * kvmppc_gsm_free() - free guest state message
+ * @gsm: guest state message
+ *
+ * Returns the size required for the message.
+ */
+void kvmppc_gsm_free(struct kvmppc_gs_msg *gsm)
+{
+	kfree(gsm);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_free);
+
+/**
+ * kvmppc_gsm_fill_info() - serialises message to guest state buffer format
+ * @gsm: self
+ * @gsb: buffer to serialise into
+ */
+int kvmppc_gsm_fill_info(struct kvmppc_gs_msg *gsm, struct kvmppc_gs_buff *gsb)
+{
+	if (!gsm->ops->fill_info)
+		return -EINVAL;
+
+	return gsm->ops->fill_info(gsb, gsm);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_fill_info);
+
+/**
+ * kvmppc_gsm_refresh_info() - deserialises from guest state buffer
+ * @gsm: self
+ * @gsb: buffer to serialise from
+ */
+int kvmppc_gsm_refresh_info(struct kvmppc_gs_msg *gsm,
+			    struct kvmppc_gs_buff *gsb)
+{
+	if (!gsm->ops->fill_info)
+		return -EINVAL;
+
+	return gsm->ops->refresh_info(gsm, gsb);
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsm_refresh_info);
+
+/**
+ * kvmppc_gsb_send - send all elements in the buffer to the hypervisor.
+ * @gsb: guest state buffer
+ * @flags: guest wide or thread wide
+ *
+ * Performs the H_GUEST_SET_STATE hcall for the guest state buffer.
+ */
+int kvmppc_gsb_send(struct kvmppc_gs_buff *gsb, unsigned long flags)
+{
+	unsigned long hflags = 0;
+	unsigned long i;
+	int rc;
+
+	if (kvmppc_gsb_nelems(gsb) == 0)
+		return 0;
+
+	if (flags & KVMPPC_GS_FLAGS_WIDE)
+		hflags |= H_GUEST_FLAGS_WIDE;
+	if (flags & KVMPPC_GS_FLAGS_HOST_WIDE)
+		hflags |= H_GUEST_FLAGS_HOST_WIDE;
+
+	rc = plpar_guest_set_state(hflags, gsb->guest_id, gsb->vcpu_id,
+				   __pa(gsb->hdr), gsb->capacity, &i);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsb_send);
+
+/**
+ * kvmppc_gsb_recv - request all elements in the buffer have their value
+ * updated.
+ * @gsb: guest state buffer
+ * @flags: guest wide or thread wide
+ *
+ * Performs the H_GUEST_GET_STATE hcall for the guest state buffer.
+ * After returning from the hcall the guest state elements that were
+ * present in the buffer will have updated values from the hypervisor.
+ */
+int kvmppc_gsb_recv(struct kvmppc_gs_buff *gsb, unsigned long flags)
+{
+	unsigned long hflags = 0;
+	unsigned long i;
+	int rc;
+
+	if (flags & KVMPPC_GS_FLAGS_WIDE)
+		hflags |= H_GUEST_FLAGS_WIDE;
+	if (flags & KVMPPC_GS_FLAGS_HOST_WIDE)
+		hflags |= H_GUEST_FLAGS_HOST_WIDE;
+
+	rc = plpar_guest_get_state(hflags, gsb->guest_id, gsb->vcpu_id,
+				   __pa(gsb->hdr), gsb->capacity, &i);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(kvmppc_gsb_recv);