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| author | Paolo Bonzini <pbonzini@redhat.com> | 2015-07-29 11:06:34 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-07-29 14:27:23 +0200 |
| commit | c847fe8895fded71d0b9a0ba58d3828320fd1824 (patch) | |
| tree | 8a2e5f7f5cf0300c3cea056c782884cfae72bde0 /arch/x86/kvm | |
| parent | KVM: move code related to KVM_SET_BOOT_CPU_ID to x86 (diff) | |
| download | linux-c847fe8895fded71d0b9a0ba58d3828320fd1824.tar.xz linux-c847fe8895fded71d0b9a0ba58d3828320fd1824.zip | |
KVM: x86: remove unnecessary memory barriers for shared MSRs
There is no smp_rmb matching the smp_wmb. shared_msr_update is called from
hardware_enable, which in turn is called via on_each_cpu. on_each_cpu
and must imply a read memory barrier (on x86 the rmb is achieved simply
through asm volatile in native_apic_mem_write).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/x86.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c675ea3351cf..2d62229aac26 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -222,11 +222,9 @@ static void shared_msr_update(unsigned slot, u32 msr) void kvm_define_shared_msr(unsigned slot, u32 msr) { BUG_ON(slot >= KVM_NR_SHARED_MSRS); + shared_msrs_global.msrs[slot] = msr; if (slot >= shared_msrs_global.nr) shared_msrs_global.nr = slot + 1; - shared_msrs_global.msrs[slot] = msr; - /* we need ensured the shared_msr_global have been updated */ - smp_wmb(); } EXPORT_SYMBOL_GPL(kvm_define_shared_msr); |