From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH] KVM: x86: fix access memslots w/o hold srcu read lock
Date: Sun, 02 Nov 2014 07:50:29 +0100
Message-ID: <5455D435.5050405@redhat.com>
References: <1414730012-7278-1-git-send-email-wanpeng.li@linux.intel.com> <54531E7B.1040006@intel.com> <5453663B.90500@redhat.com> <54544A45.1000505@gmail.com>
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Cc: Gleb Natapov <gleb@kernel.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Takashi Iwai <tiwai@suse.de>, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Wanpeng Li <kernellwp@gmail.com>,
	"Chen, Tiejun" <tiejun.chen@intel.com>,
	Wanpeng Li <wanpeng.li@linux.intel.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <54544A45.1000505@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org



On 01/11/2014 03:49, Wanpeng Li wrote:
> 
> This is also not enough. I see the warning in the below path during the
> test:
> 
> kvm_arch_vcpu_ioctl_run
> -> kvm_apic_accept_events
> -> kvm_vcpu_reset

Hmm, better bypass the problem altogether:

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a0f78dbaabee..3e556c68351b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4579,7 +4579,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 		vmcs_write32(TPR_THRESHOLD, 0);
 	}
 
-	kvm_vcpu_reload_apic_access_page(vcpu);
+	kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu);
 
 	if (vmx_vm_has_apicv(vcpu->kvm))
 		memset(&vmx->pi_desc, 0, sizeof(struct pi_desc));

(untested)

Paolo