Re: [PATCH RESEND v4] powerpc: kvm: fix rare but potential deadlock scene

2013-11-20 Thread Alexander Graf
Am 20.11.2013 um 03:42 schrieb Liu ping fan kernelf...@gmail.com: On Tue, Nov 19, 2013 at 6:39 PM, Alexander Graf ag...@suse.de wrote: On 19.11.2013, at 07:12, Liu Ping Fan kernelf...@gmail.com wrote: Since kvmppc_hv_find_lock_hpte() is called from both virtmode and realmode, so it

Re: [PATCH RESEND v4] powerpc: kvm: fix rare but potential deadlock scene

2013-11-19 Thread Alexander Graf
On 19.11.2013, at 07:12, Liu Ping Fan kernelf...@gmail.com wrote: Since kvmppc_hv_find_lock_hpte() is called from both virtmode and realmode, so it can trigger the deadlock. Suppose the following scene: Two physical cpuM, cpuN, two VM instances A, B, each VM has a group of vcpus. If

Re: [PATCH RESEND v4] powerpc: kvm: fix rare but potential deadlock scene

2013-11-19 Thread Liu ping fan
On Tue, Nov 19, 2013 at 6:39 PM, Alexander Graf ag...@suse.de wrote: On 19.11.2013, at 07:12, Liu Ping Fan kernelf...@gmail.com wrote: Since kvmppc_hv_find_lock_hpte() is called from both virtmode and realmode, so it can trigger the deadlock. Suppose the following scene: Two physical

[PATCH RESEND v4] powerpc: kvm: fix rare but potential deadlock scene

2013-11-18 Thread Liu Ping Fan
Since kvmppc_hv_find_lock_hpte() is called from both virtmode and realmode, so it can trigger the deadlock. Suppose the following scene: Two physical cpuM, cpuN, two VM instances A, B, each VM has a group of vcpus. If on cpuM, vcpu_A_1 holds bitlock X (HPTE_V_HVLOCK), then is switched out, and