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

2013-11-18 Thread Alexander Graf
On 18.11.2013, at 16:32, Alexander Graf wrote: > > On 16.11.2013, at 01:55, Paul Mackerras wrote: > >> On Fri, Nov 15, 2013 at 04:35:00PM +0800, Liu Ping Fan wrote: >>> Since kvmppc_hv_find_lock_hpte() is called from both virtmode and >>> realmode, so it can trigger the deadlock. >>> >>> Sup

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

2013-11-18 Thread Alexander Graf
On 16.11.2013, at 01:55, Paul Mackerras wrote: > On Fri, Nov 15, 2013 at 04:35:00PM +0800, Liu Ping Fan 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

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

2013-11-15 Thread Paul Mackerras
On Fri, Nov 15, 2013 at 04:35:00PM +0800, Liu Ping Fan 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. > > I

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

2013-11-15 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 o