From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Egger, Christoph" Subject: Re: [PATCH] x86/MCE: bypass uninitialized vcpu in vMCE injection Date: Wed, 7 May 2014 15:25:04 +0200 Message-ID: <536A3430.9060408@amazon.de> References: <1399447758-11798-1-git-send-email-kai.huang@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1399447758-11798-1-git-send-email-kai.huang@linux.intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Kai Huang , xen-devel@lists.xen.org Cc: yang.z.zhang@intel.com, jinsong.liu@alibaba-inc.com, kevin.tian@intel.com, dongxiao.xu@intel.com, JBeulich@suse.com List-Id: xen-devel@lists.xenproject.org On 07.05.14 09:29, Kai Huang wrote: > Dom0 may bring up less number of vCPUs than xen hypervisor actually created for > it, and in this case, on Intel platform, vMCE injection to dom0 will fail due to > injecting vMCE to uninitialized vcpu, and cause dom0 crash. > > Signed-off-by: Kai Huang > --- > xen/arch/x86/cpu/mcheck/vmce.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/xen/arch/x86/cpu/mcheck/vmce.c b/xen/arch/x86/cpu/mcheck/vmce.c > index c83375e..72fe924 100644 > --- a/xen/arch/x86/cpu/mcheck/vmce.c > +++ b/xen/arch/x86/cpu/mcheck/vmce.c > @@ -356,6 +356,10 @@ int inject_vmce(struct domain *d, int vcpu) > if ( vcpu != VMCE_INJECT_BROADCAST && vcpu != v->vcpu_id ) > continue; > > + /* In case of broadcasting, don't inject to uninitialized VCPU */ > + if ( vcpu == VMCE_INJECT_BROADCAST && !v->is_initialised ) > + continue; > + What happens when you inject to exactly one uninitialized VCPU? I think what you want is this: /* Don't inject to uninitialized VCPU */ if ( !v->is_initialised ) continue; > if ( (has_hvm_container_domain(d) || > guest_has_trap_callback(d, v->vcpu_id, TRAP_machine_check)) && > !test_and_set_bool(v->mce_pending) ) >