133 lines
4.4 KiB
Diff
133 lines
4.4 KiB
Diff
From ffbd90e5f4eba620c7cd631b04f0ed31beb22ffa Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Tue, 17 May 2022 12:07:56 +0100
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Subject: [PATCH 1/6] coroutine-ucontext: use QEMU_DEFINE_STATIC_CO_TLS()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
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RH-MergeRequest: 89: coroutine: use coroutine TLS macros to protect thread-local variables
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RH-Commit: [1/3] a9782fe8e919c4bd317b7e8744c7ff57d898add3 (stefanha/centos-stream-qemu-kvm)
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RH-Bugzilla: 1952483
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RH-Acked-by: Hanna Reitz <hreitz@redhat.com>
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RH-Acked-by: Eric Blake <eblake@redhat.com>
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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Thread-Local Storage variables cannot be used directly from coroutine
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code because the compiler may optimize TLS variable accesses across
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qemu_coroutine_yield() calls. When the coroutine is re-entered from
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another thread the TLS variables from the old thread must no longer be
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used.
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Use QEMU_DEFINE_STATIC_CO_TLS() for the current and leader variables.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Message-Id: <20220307153853.602859-2-stefanha@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 34145a307d849d0b6734d0222a7aa0bb9eef7407)
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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util/coroutine-ucontext.c | 38 ++++++++++++++++++++++++--------------
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1 file changed, 24 insertions(+), 14 deletions(-)
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diff --git a/util/coroutine-ucontext.c b/util/coroutine-ucontext.c
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index 904b375192..127d5a13c8 100644
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--- a/util/coroutine-ucontext.c
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+++ b/util/coroutine-ucontext.c
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@@ -25,6 +25,7 @@
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#include "qemu/osdep.h"
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#include <ucontext.h>
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#include "qemu/coroutine_int.h"
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+#include "qemu/coroutine-tls.h"
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#ifdef CONFIG_VALGRIND_H
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#include <valgrind/valgrind.h>
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@@ -66,8 +67,8 @@ typedef struct {
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/**
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* Per-thread coroutine bookkeeping
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*/
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-static __thread CoroutineUContext leader;
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-static __thread Coroutine *current;
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+QEMU_DEFINE_STATIC_CO_TLS(Coroutine *, current);
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+QEMU_DEFINE_STATIC_CO_TLS(CoroutineUContext, leader);
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/*
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* va_args to makecontext() must be type 'int', so passing
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@@ -97,14 +98,15 @@ static inline __attribute__((always_inline))
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void finish_switch_fiber(void *fake_stack_save)
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{
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#ifdef CONFIG_ASAN
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+ CoroutineUContext *leaderp = get_ptr_leader();
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const void *bottom_old;
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size_t size_old;
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__sanitizer_finish_switch_fiber(fake_stack_save, &bottom_old, &size_old);
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- if (!leader.stack) {
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- leader.stack = (void *)bottom_old;
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- leader.stack_size = size_old;
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+ if (!leaderp->stack) {
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+ leaderp->stack = (void *)bottom_old;
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+ leaderp->stack_size = size_old;
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}
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#endif
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#ifdef CONFIG_TSAN
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@@ -161,8 +163,10 @@ static void coroutine_trampoline(int i0, int i1)
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/* Initialize longjmp environment and switch back the caller */
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if (!sigsetjmp(self->env, 0)) {
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- start_switch_fiber_asan(COROUTINE_YIELD, &fake_stack_save, leader.stack,
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- leader.stack_size);
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+ CoroutineUContext *leaderp = get_ptr_leader();
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+
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+ start_switch_fiber_asan(COROUTINE_YIELD, &fake_stack_save,
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+ leaderp->stack, leaderp->stack_size);
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start_switch_fiber_tsan(&fake_stack_save, self, true); /* true=caller */
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siglongjmp(*(sigjmp_buf *)co->entry_arg, 1);
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}
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@@ -297,7 +301,7 @@ qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
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int ret;
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void *fake_stack_save = NULL;
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- current = to_;
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+ set_current(to_);
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ret = sigsetjmp(from->env, 0);
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if (ret == 0) {
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@@ -315,18 +319,24 @@ qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
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Coroutine *qemu_coroutine_self(void)
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{
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- if (!current) {
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- current = &leader.base;
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+ Coroutine *self = get_current();
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+ CoroutineUContext *leaderp = get_ptr_leader();
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+
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+ if (!self) {
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+ self = &leaderp->base;
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+ set_current(self);
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}
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#ifdef CONFIG_TSAN
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- if (!leader.tsan_co_fiber) {
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- leader.tsan_co_fiber = __tsan_get_current_fiber();
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+ if (!leaderp->tsan_co_fiber) {
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+ leaderp->tsan_co_fiber = __tsan_get_current_fiber();
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}
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#endif
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- return current;
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+ return self;
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}
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bool qemu_in_coroutine(void)
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{
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- return current && current->caller;
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+ Coroutine *self = get_current();
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+
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+ return self && self->caller;
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}
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--
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2.31.1
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