Commit 5a48a622 authored Apr 11, 2017 by Wanpeng Li Committed by Radim Krčmář Apr 12, 2017

x86/kvm: virt_xxx memory barriers instead of mandatory barriers

virt_xxx memory barriers are implemented trivially using the low-level
__smp_xxx macros, __smp_xxx is equal to a compiler barrier for strong
TSO memory model, however, mandatory barriers will unconditional add
memory barriers, this patch replaces the rmb() in kvm_steal_clock() by
virt_rmb().

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

parent bd8fab39

arch/x86/kernel/kvm.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -396,9 +396,9 @@ static u64 kvm_steal_clock(int cpu)
	src = &per_cpu(steal_time, cpu);		src = &per_cpu(steal_time, cpu);
	do {		do {
	version = src->version;		version = src->version;
	rmb();		virt_rmb();
	steal = src->steal;		steal = src->steal;
	rmb();		virt_rmb();
	} while ((version & 1) \|\| (version != src->version));		} while ((version & 1) \|\| (version != src->version));

	return steal;		return steal;