From 758ccc89b83cc15d575204091c1a1fec306245cb Mon Sep 17 00:00:00 2001 From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Date: Fri, 31 May 2013 08:36:20 +0800 Subject: [PATCH] KVM: x86: drop calling kvm_mmu_zap_all in emulator_fix_hypercall Quote Gleb's mail: | Back then kvm->lock protected memslot access so code like: | | mutex_lock(&vcpu->kvm->lock); | kvm_mmu_zap_all(vcpu->kvm); | mutex_unlock(&vcpu->kvm->lock); | | which is what 7aa81cc0 does was enough to guaranty that no vcpu will | run while code is patched. This is no longer the case and | mutex_lock(&vcpu->kvm->lock); is gone from that code path long time ago, | so now kvm_mmu_zap_all() there is useless and the code is incorrect. So we drop it and it will be fixed later Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> --- arch/x86/kvm/x86.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8d28810a5f88..6739b1d4ce7c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5523,13 +5523,6 @@ static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt) char instruction[3]; unsigned long rip = kvm_rip_read(vcpu); - /* - * Blow out the MMU to ensure that no other VCPU has an active mapping - * to ensure that the updated hypercall appears atomically across all - * VCPUs. - */ - kvm_mmu_zap_all(vcpu->kvm); - kvm_x86_ops->patch_hypercall(vcpu, instruction); return emulator_write_emulated(ctxt, rip, instruction, 3, NULL); -- 2.34.1