52e850dea9
Some state is shared between the block migration code and its AIO callbacks. Once block migration will run outside the iothread, the block migration code and the AIO callbacks will be able to run concurrently. Protect the critical sections with a separate lock. Do the same for completed_sectors, which can be used from the monitor. Reviewed-by: Orit Wasserman <owasserm@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
#ifndef __QEMU_BARRIER_H
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#define __QEMU_BARRIER_H 1
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/* Compiler barrier */
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#define barrier() asm volatile("" ::: "memory")
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#if defined(__i386__)
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#include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */
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/*
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* Because of the strongly ordered x86 storage model, wmb() and rmb() are nops
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* on x86(well, a compiler barrier only). Well, at least as long as
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* qemu doesn't do accesses to write-combining memory or non-temporal
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* load/stores from C code.
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*/
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#define smp_wmb() barrier()
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#define smp_rmb() barrier()
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/*
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* We use GCC builtin if it's available, as that can use
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* mfence on 32 bit as well, e.g. if built with -march=pentium-m.
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* However, on i386, there seem to be known bugs as recently as 4.3.
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* */
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#if QEMU_GNUC_PREREQ(4, 4)
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#define smp_mb() __sync_synchronize()
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#else
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#define smp_mb() asm volatile("lock; addl $0,0(%%esp) " ::: "memory")
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#endif
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#elif defined(__x86_64__)
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#define smp_wmb() barrier()
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#define smp_rmb() barrier()
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#define smp_mb() asm volatile("mfence" ::: "memory")
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#elif defined(_ARCH_PPC)
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/*
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* We use an eieio() for wmb() on powerpc. This assumes we don't
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* need to order cacheable and non-cacheable stores with respect to
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* each other
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*/
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#define smp_wmb() asm volatile("eieio" ::: "memory")
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#if defined(__powerpc64__)
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#define smp_rmb() asm volatile("lwsync" ::: "memory")
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#else
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#define smp_rmb() asm volatile("sync" ::: "memory")
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#endif
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#define smp_mb() asm volatile("sync" ::: "memory")
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#else
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/*
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* For (host) platforms we don't have explicit barrier definitions
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* for, we use the gcc __sync_synchronize() primitive to generate a
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* full barrier. This should be safe on all platforms, though it may
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* be overkill for wmb() and rmb().
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*/
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#define smp_wmb() __sync_synchronize()
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#define smp_mb() __sync_synchronize()
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#define smp_rmb() __sync_synchronize()
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#endif
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#endif
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