Merge remote-tracking branch 'remotes/stefanha-gitlab/tags/block-pull-request' into staging

Pull request

v2:
 * Removed clang-format call from scripts/block-coroutine-wrapper.py. This
   avoids the issue with clang version incompatibility. It could be added back
   in the future but the code is readable without reformatting and it also
   makes the build less dependent on the environment.

# gpg: Signature made Mon 05 Oct 2020 16:42:28 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha-gitlab/tags/block-pull-request:
  util/vfio-helpers: Rework the IOVA allocator to avoid IOVA reserved regions
  util/vfio-helpers: Collect IOVA reserved regions
  docs: add 'io_uring' option to 'aio' param in qemu-options.hx
  include/block/block.h: drop non-ascii quotation mark
  block/io: refactor save/load vmstate
  block: drop bdrv_prwv
  block: generate coroutine-wrapper code
  scripts: add block-coroutine-wrapper.py
  block: declare some coroutine functions in block/coroutines.h
  block/io: refactor coroutine wrappers
  block: return error-code from bdrv_invalidate_cache
  block/nvme: Replace magic value by SCALE_MS definition
  block/nvme: Use register definitions from 'block/nvme.h'
  block/nvme: Drop NVMeRegs structure, directly use NvmeBar
  block/nvme: Reduce I/O registers scope
  block/nvme: Map doorbells pages write-only
  util/vfio-helpers: Pass page protections to qemu_vfio_pci_map_bar()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/scripts/block-coroutine-wrapper.py b/scripts/block-coroutine-wrapper.py
new file mode 100644
index 0000000000..0461fd1c45
--- /dev/null
+++ b/scripts/block-coroutine-wrapper.py
@@ -0,0 +1,167 @@
+#! /usr/bin/env python3
+"""Generate coroutine wrappers for block subsystem.
+
+The program parses one or several concatenated c files from stdin,
+searches for functions with the 'generated_co_wrapper' specifier
+and generates corresponding wrappers on stdout.
+
+Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...
+
+Copyright (c) 2020 Virtuozzo International GmbH.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+
+import sys
+import re
+from typing import Iterator
+
+
+def gen_header():
+    copyright = re.sub('^.*Copyright', 'Copyright', __doc__, flags=re.DOTALL)
+    copyright = re.sub('^(?=.)', ' * ', copyright.strip(), flags=re.MULTILINE)
+    copyright = re.sub('^$', ' *', copyright, flags=re.MULTILINE)
+    return f"""\
+/*
+ * File is generated by scripts/block-coroutine-wrapper.py
+ *
+{copyright}
+ */
+
+#include "qemu/osdep.h"
+#include "block/coroutines.h"
+#include "block/block-gen.h"
+#include "block/block_int.h"\
+"""
+
+
+class ParamDecl:
+    param_re = re.compile(r'(?P<decl>'
+                          r'(?P<type>.*[ *])'
+                          r'(?P<name>[a-z][a-z0-9_]*)'
+                          r')')
+
+    def __init__(self, param_decl: str) -> None:
+        m = self.param_re.match(param_decl.strip())
+        if m is None:
+            raise ValueError(f'Wrong parameter declaration: "{param_decl}"')
+        self.decl = m.group('decl')
+        self.type = m.group('type')
+        self.name = m.group('name')
+
+
+class FuncDecl:
+    def __init__(self, return_type: str, name: str, args: str) -> None:
+        self.return_type = return_type.strip()
+        self.name = name.strip()
+        self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
+
+    def gen_list(self, format: str) -> str:
+        return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
+
+    def gen_block(self, format: str) -> str:
+        return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)
+
+
+# Match wrappers declared with a generated_co_wrapper mark
+func_decl_re = re.compile(r'^int\s*generated_co_wrapper\s*'
+                          r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
+                          r'\((?P<args>[^)]*)\);$', re.MULTILINE)
+
+
+def func_decl_iter(text: str) -> Iterator:
+    for m in func_decl_re.finditer(text):
+        yield FuncDecl(return_type='int',
+                       name=m.group('wrapper_name'),
+                       args=m.group('args'))
+
+
+def snake_to_camel(func_name: str) -> str:
+    """
+    Convert underscore names like 'some_function_name' to camel-case like
+    'SomeFunctionName'
+    """
+    words = func_name.split('_')
+    words = [w[0].upper() + w[1:] for w in words]
+    return ''.join(words)
+
+
+def gen_wrapper(func: FuncDecl) -> str:
+    assert func.name.startswith('bdrv_')
+    assert not func.name.startswith('bdrv_co_')
+    assert func.return_type == 'int'
+    assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *']
+
+    name = 'bdrv_co_' + func.name[5:]
+    bs = 'bs' if func.args[0].type == 'BlockDriverState *' else 'child->bs'
+    struct_name = snake_to_camel(name)
+
+    return f"""\
+/*
+ * Wrappers for {name}
+ */
+
+typedef struct {struct_name} {{
+    BdrvPollCo poll_state;
+{ func.gen_block('    {decl};') }
+}} {struct_name};
+
+static void coroutine_fn {name}_entry(void *opaque)
+{{
+    {struct_name} *s = opaque;
+
+    s->poll_state.ret = {name}({ func.gen_list('s->{name}') });
+    s->poll_state.in_progress = false;
+
+    aio_wait_kick();
+}}
+
+int {func.name}({ func.gen_list('{decl}') })
+{{
+    if (qemu_in_coroutine()) {{
+        return {name}({ func.gen_list('{name}') });
+    }} else {{
+        {struct_name} s = {{
+            .poll_state.bs = {bs},
+            .poll_state.in_progress = true,
+
+{ func.gen_block('            .{name} = {name},') }
+        }};
+
+        s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
+
+        return bdrv_poll_co(&s.poll_state);
+    }}
+}}"""
+
+
+def gen_wrappers(input_code: str) -> str:
+    res = ''
+    for func in func_decl_iter(input_code):
+        res += '\n\n\n'
+        res += gen_wrapper(func)
+
+    return res
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 3:
+        exit(f'Usage: {sys.argv[0]} OUT_FILE.c IN_FILE.[ch]...')
+
+    with open(sys.argv[1], 'w', encoding='utf-8') as f_out:
+        f_out.write(gen_header())
+        for fname in sys.argv[2:]:
+            with open(fname, encoding='utf-8') as f_in:
+                f_out.write(gen_wrappers(f_in.read()))
+                f_out.write('\n')