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, 599 insertions, 0 deletions

diff --git a/scripts/dtc/dtc-parser.y b/scripts/dtc/dtc-parser.y
new file mode 100644
index 000000000..4d5eece52
--- /dev/null
+++ b/scripts/dtc/dtc-parser.y
@@ -0,0 +1,599 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * (C) Copyright David Gibson <dwg@au1.ibm.com>, IBM Corporation.  2005.
+ */
+%locations
+
+%{
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "dtc.h"
+#include "srcpos.h"
+
+extern int yylex(void);
+extern void yyerror(char const *s);
+#define ERROR(loc, ...) \
+	do { \
+		srcpos_error((loc), "Error", __VA_ARGS__); \
+		treesource_error = true; \
+	} while (0)
+
+#define YYERROR_CALL(msg) yyerror(msg)
+
+extern struct dt_info *parser_output;
+extern bool treesource_error;
+
+static bool is_ref_relative(const char *ref)
+{
+	return ref[0] != '/' && strchr(&ref[1], '/');
+}
+
+%}
+
+%union {
+	char *propnodename;
+	char *labelref;
+	uint8_t byte;
+	struct data data;
+
+	struct {
+		struct data	data;
+		int		bits;
+	} array;
+
+	struct property *prop;
+	struct property *proplist;
+	struct node *node;
+	struct node *nodelist;
+	struct reserve_info *re;
+	uint64_t integer;
+	unsigned int flags;
+}
+
+%token DT_V1
+%token DT_PLUGIN
+%token DT_MEMRESERVE
+%token DT_LSHIFT DT_RSHIFT DT_LE DT_GE DT_EQ DT_NE DT_AND DT_OR
+%token DT_BITS
+%token DT_DEL_PROP
+%token DT_DEL_NODE
+%token DT_OMIT_NO_REF
+%token <propnodename> DT_PROPNODENAME
+%token <integer> DT_LITERAL
+%token <integer> DT_CHAR_LITERAL
+%token <byte> DT_BYTE
+%token <data> DT_STRING
+%token <labelref> DT_LABEL
+%token <labelref> DT_LABEL_REF
+%token <labelref> DT_PATH_REF
+%token DT_INCBIN
+
+%type <data> propdata
+%type <data> propdataprefix
+%type <flags> header
+%type <flags> headers
+%type <re> memreserve
+%type <re> memreserves
+%type <array> arrayprefix
+%type <data> bytestring
+%type <prop> propdef
+%type <proplist> proplist
+%type <labelref> dt_ref
+
+%type <node> devicetree
+%type <node> nodedef
+%type <node> subnode
+%type <nodelist> subnodes
+
+%type <integer> integer_prim
+%type <integer> integer_unary
+%type <integer> integer_mul
+%type <integer> integer_add
+%type <integer> integer_shift
+%type <integer> integer_rela
+%type <integer> integer_eq
+%type <integer> integer_bitand
+%type <integer> integer_bitxor
+%type <integer> integer_bitor
+%type <integer> integer_and
+%type <integer> integer_or
+%type <integer> integer_trinary
+%type <integer> integer_expr
+
+%%
+
+sourcefile:
+	  headers memreserves devicetree
+		{
+			parser_output = build_dt_info($1, $2, $3,
+			                              guess_boot_cpuid($3));
+		}
+	;
+
+header:
+	  DT_V1 ';'
+		{
+			$$ = DTSF_V1;
+		}
+	| DT_V1 ';' DT_PLUGIN ';'
+		{
+			$$ = DTSF_V1 | DTSF_PLUGIN;
+		}
+	;
+
+headers:
+	  header
+	| header headers
+		{
+			if ($2 != $1)
+				ERROR(&@2, "Header flags don't match earlier ones");
+			$$ = $1;
+		}
+	;
+
+memreserves:
+	  /* empty */
+		{
+			$$ = NULL;
+		}
+	| memreserve memreserves
+		{
+			$$ = chain_reserve_entry($1, $2);
+		}
+	;
+
+memreserve:
+	  DT_MEMRESERVE integer_prim integer_prim ';'
+		{
+			$$ = build_reserve_entry($2, $3);
+		}
+	| DT_LABEL memreserve
+		{
+			add_label(&$2->labels, $1);
+			$$ = $2;
+		}
+	;
+
+dt_ref: DT_LABEL_REF | DT_PATH_REF;
+
+devicetree:
+	  '/' nodedef
+		{
+			$$ = name_node($2, "");
+		}
+	| devicetree '/' nodedef
+		{
+			$$ = merge_nodes($1, $3);
+		}
+	| dt_ref nodedef
+		{
+			/*
+			 * We rely on the rule being always:
+			 *   versioninfo plugindecl memreserves devicetree
+			 * so $-1 is what we want (plugindecl)
+			 */
+			if (!($<flags>-1 & DTSF_PLUGIN))
+				ERROR(&@2, "Label or path %s not found", $1);
+			else if (is_ref_relative($1))
+				ERROR(&@2, "Label-relative reference %s not supported in plugin", $1);
+			$$ = add_orphan_node(
+					name_node(build_node(NULL, NULL, NULL),
+						  ""),
+					$2, $1);
+		}
+	| devicetree DT_LABEL dt_ref nodedef
+		{
+			struct node *target = get_node_by_ref($1, $3);
+
+			if (($<flags>-1 & DTSF_PLUGIN) && is_ref_relative($3))
+				ERROR(&@2, "Label-relative reference %s not supported in plugin", $3);
+
+			if (target) {
+				add_label(&target->labels, $2);
+				merge_nodes(target, $4);
+			} else
+				ERROR(&@3, "Label or path %s not found", $3);
+			$$ = $1;
+		}
+	| devicetree DT_PATH_REF nodedef
+		{
+			/*
+			 * We rely on the rule being always:
+			 *   versioninfo plugindecl memreserves devicetree
+			 * so $-1 is what we want (plugindecl)
+			 */
+			if ($<flags>-1 & DTSF_PLUGIN) {
+				if (is_ref_relative($2))
+					ERROR(&@2, "Label-relative reference %s not supported in plugin", $2);
+				add_orphan_node($1, $3, $2);
+			} else {
+				struct node *target = get_node_by_ref($1, $2);
+
+				if (target)
+					merge_nodes(target, $3);
+				else
+					ERROR(&@2, "Label or path %s not found", $2);
+			}
+			$$ = $1;
+		}
+	| devicetree DT_LABEL_REF nodedef
+		{
+			struct node *target = get_node_by_ref($1, $2);
+
+			if (target) {
+				merge_nodes(target, $3);
+			} else {
+				/*
+				 * We rely on the rule being always:
+				 *   versioninfo plugindecl memreserves devicetree
+				 * so $-1 is what we want (plugindecl)
+				 */
+				if ($<flags>-1 & DTSF_PLUGIN)
+					add_orphan_node($1, $3, $2);
+				else
+					ERROR(&@2, "Label or path %s not found", $2);
+			}
+			$$ = $1;
+		}
+	| devicetree DT_DEL_NODE dt_ref ';'
+		{
+			struct node *target = get_node_by_ref($1, $3);
+
+			if (target)
+				delete_node(target);
+			else
+				ERROR(&@3, "Label or path %s not found", $3);
+
+
+			$$ = $1;
+		}
+	| devicetree DT_OMIT_NO_REF dt_ref ';'
+		{
+			struct node *target = get_node_by_ref($1, $3);
+
+			if (target)
+				omit_node_if_unused(target);
+			else
+				ERROR(&@3, "Label or path %s not found", $3);
+
+
+			$$ = $1;
+		}
+	;
+
+nodedef:
+	  '{' proplist subnodes '}' ';'
+		{
+			$$ = build_node($2, $3, &@$);
+		}
+	;
+
+proplist:
+	  /* empty */
+		{
+			$$ = NULL;
+		}
+	| proplist propdef
+		{
+			$$ = chain_property($2, $1);
+		}
+	;
+
+propdef:
+	  DT_PROPNODENAME '=' propdata ';'
+		{
+			$$ = build_property($1, $3, &@$);
+			free($1);
+		}
+	| DT_PROPNODENAME ';'
+		{
+			$$ = build_property($1, empty_data, &@$);
+			free($1);
+		}
+	| DT_DEL_PROP DT_PROPNODENAME ';'
+		{
+			$$ = build_property_delete($2);
+			free($2);
+		}
+	| DT_LABEL propdef
+		{
+			add_label(&$2->labels, $1);
+			$$ = $2;
+		}
+	;
+
+propdata:
+	  propdataprefix DT_STRING
+		{
+			$$ = data_merge($1, $2);
+		}
+	| propdataprefix arrayprefix '>'
+		{
+			$$ = data_merge($1, $2.data);
+		}
+	| propdataprefix '[' bytestring ']'
+		{
+			$$ = data_merge($1, $3);
+		}
+	| propdataprefix dt_ref
+		{
+			$1 = data_add_marker($1, TYPE_STRING, $2);
+			$$ = data_add_marker($1, REF_PATH, $2);
+		}
+	| propdataprefix DT_INCBIN '(' DT_STRING ',' integer_prim ',' integer_prim ')'
+		{
+			FILE *f = srcfile_relative_open($4.val, NULL);
+			struct data d;
+
+			if ($6 != 0)
+				if (fseek(f, $6, SEEK_SET) != 0)
+					die("Couldn't seek to offset %llu in \"%s\": %s",
+					    (unsigned long long)$6, $4.val,
+					    strerror(errno));
+
+			d = data_copy_file(f, $8);
+
+			$$ = data_merge($1, d);
+			fclose(f);
+		}
+	| propdataprefix DT_INCBIN '(' DT_STRING ')'
+		{
+			FILE *f = srcfile_relative_open($4.val, NULL);
+			struct data d = empty_data;
+
+			d = data_copy_file(f, -1);
+
+			$$ = data_merge($1, d);
+			fclose(f);
+		}
+	| propdata DT_LABEL
+		{
+			$$ = data_add_marker($1, LABEL, $2);
+		}
+	;
+
+propdataprefix:
+	  /* empty */
+		{
+			$$ = empty_data;
+		}
+	| propdata ','
+		{
+			$$ = $1;
+		}
+	| propdataprefix DT_LABEL
+		{
+			$$ = data_add_marker($1, LABEL, $2);
+		}
+	;
+
+arrayprefix:
+	DT_BITS DT_LITERAL '<'
+		{
+			unsigned long long bits;
+			enum markertype type = TYPE_UINT32;
+
+			bits = $2;
+
+			switch (bits) {
+			case 8: type = TYPE_UINT8; break;
+			case 16: type = TYPE_UINT16; break;
+			case 32: type = TYPE_UINT32; break;
+			case 64: type = TYPE_UINT64; break;
+			default:
+				ERROR(&@2, "Array elements must be"
+				      " 8, 16, 32 or 64-bits");
+				bits = 32;
+			}
+
+			$$.data = data_add_marker(empty_data, type, NULL);
+			$$.bits = bits;
+		}
+	| '<'
+		{
+			$$.data = data_add_marker(empty_data, TYPE_UINT32, NULL);
+			$$.bits = 32;
+		}
+	| arrayprefix integer_prim
+		{
+			if ($1.bits < 64) {
+				uint64_t mask = (1ULL << $1.bits) - 1;
+				/*
+				 * Bits above mask must either be all zero
+				 * (positive within range of mask) or all one
+				 * (negative and sign-extended). The second
+				 * condition is true if when we set all bits
+				 * within the mask to one (i.e. | in the
+				 * mask), all bits are one.
+				 */
+				if (($2 > mask) && (($2 | mask) != -1ULL)) {
+					char *loc = srcpos_string(&@2);
+					fprintf(stderr,
+						"WARNING: %s: Value 0x%016" PRIx64
+						" truncated to 0x%0*" PRIx64 "\n",
+						loc, $2, $1.bits / 4, ($2 & mask));
+					free(loc);
+				}
+			}
+
+			$$.data = data_append_integer($1.data, $2, $1.bits);
+		}
+	| arrayprefix dt_ref
+		{
+			uint64_t val = ~0ULL >> (64 - $1.bits);
+
+			if ($1.bits == 32)
+				$1.data = data_add_marker($1.data,
+							  REF_PHANDLE,
+							  $2);
+			else
+				ERROR(&@2, "References are only allowed in "
+					    "arrays with 32-bit elements.");
+
+			$$.data = data_append_integer($1.data, val, $1.bits);
+		}
+	| arrayprefix DT_LABEL
+		{
+			$$.data = data_add_marker($1.data, LABEL, $2);
+		}
+	;
+
+integer_prim:
+	  DT_LITERAL
+	| DT_CHAR_LITERAL
+	| '(' integer_expr ')'
+		{
+			$$ = $2;
+		}
+	;
+
+integer_expr:
+	integer_trinary
+	;
+
+integer_trinary:
+	  integer_or
+	| integer_or '?' integer_expr ':' integer_trinary { $$ = $1 ? $3 : $5; }
+	;
+
+integer_or:
+	  integer_and
+	| integer_or DT_OR integer_and { $$ = $1 || $3; }
+	;
+
+integer_and:
+	  integer_bitor
+	| integer_and DT_AND integer_bitor { $$ = $1 && $3; }
+	;
+
+integer_bitor:
+	  integer_bitxor
+	| integer_bitor '|' integer_bitxor { $$ = $1 | $3; }
+	;
+
+integer_bitxor:
+	  integer_bitand
+	| integer_bitxor '^' integer_bitand { $$ = $1 ^ $3; }
+	;
+
+integer_bitand:
+	  integer_eq
+	| integer_bitand '&' integer_eq { $$ = $1 & $3; }
+	;
+
+integer_eq:
+	  integer_rela
+	| integer_eq DT_EQ integer_rela { $$ = $1 == $3; }
+	| integer_eq DT_NE integer_rela { $$ = $1 != $3; }
+	;
+
+integer_rela:
+	  integer_shift
+	| integer_rela '<' integer_shift { $$ = $1 < $3; }
+	| integer_rela '>' integer_shift { $$ = $1 > $3; }
+	| integer_rela DT_LE integer_shift { $$ = $1 <= $3; }
+	| integer_rela DT_GE integer_shift { $$ = $1 >= $3; }
+	;
+
+integer_shift:
+	  integer_shift DT_LSHIFT integer_add { $$ = ($3 < 64) ? ($1 << $3) : 0; }
+	| integer_shift DT_RSHIFT integer_add { $$ = ($3 < 64) ? ($1 >> $3) : 0; }
+	| integer_add
+	;
+
+integer_add:
+	  integer_add '+' integer_mul { $$ = $1 + $3; }
+	| integer_add '-' integer_mul { $$ = $1 - $3; }
+	| integer_mul
+	;
+
+integer_mul:
+	  integer_mul '*' integer_unary { $$ = $1 * $3; }
+	| integer_mul '/' integer_unary
+		{
+			if ($3 != 0) {
+				$$ = $1 / $3;
+			} else {
+				ERROR(&@$, "Division by zero");
+				$$ = 0;
+			}
+		}
+	| integer_mul '%' integer_unary
+		{
+			if ($3 != 0) {
+				$$ = $1 % $3;
+			} else {
+				ERROR(&@$, "Division by zero");
+				$$ = 0;
+			}
+		}
+	| integer_unary
+	;
+
+integer_unary:
+	  integer_prim
+	| '-' integer_unary { $$ = -$2; }
+	| '~' integer_unary { $$ = ~$2; }
+	| '!' integer_unary { $$ = !$2; }
+	;
+
+bytestring:
+	  /* empty */
+		{
+			$$ = data_add_marker(empty_data, TYPE_UINT8, NULL);
+		}
+	| bytestring DT_BYTE
+		{
+			$$ = data_append_byte($1, $2);
+		}
+	| bytestring DT_LABEL
+		{
+			$$ = data_add_marker($1, LABEL, $2);
+		}
+	;
+
+subnodes:
+	  /* empty */
+		{
+			$$ = NULL;
+		}
+	| subnode subnodes
+		{
+			$$ = chain_node($1, $2);
+		}
+	| subnode propdef
+		{
+			ERROR(&@2, "Properties must precede subnodes");
+			YYERROR;
+		}
+	;
+
+subnode:
+	  DT_PROPNODENAME nodedef
+		{
+			$$ = name_node($2, $1);
+			free($1);
+		}
+	| DT_DEL_NODE DT_PROPNODENAME ';'
+		{
+			$$ = name_node(build_node_delete(&@$), $2);
+			free($2);
+		}
+	| DT_OMIT_NO_REF subnode
+		{
+			$$ = omit_node_if_unused($2);
+		}
+	| DT_LABEL subnode
+		{
+			add_label(&$2->labels, $1);
+			$$ = $2;
+		}
+	;
+
+%%
+
+void yyerror(char const *s)
+{
+	ERROR(&yylloc, "%s", s);
+}