Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Avi Kivity
On 01/31/2011 04:31 PM, Jan Kiszka wrote: >> >> And how would you be kicked out of the select() call if it is waiting >> with a timeout? We only have a single thread here. > > If we use signalfd() (either kernel provided or thread+pipe), we kick > out of select by select()ing it (though I don

Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Jan Kiszka
On 2011-01-31 14:22, Avi Kivity wrote: > On 01/31/2011 01:27 PM, Jan Kiszka wrote: >> On 2011-01-31 11:03, Avi Kivity wrote: >>> On 01/27/2011 04:33 PM, Jan Kiszka wrote: Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between checking for exit_request on vcpu entry and timer

Re: [Qemu-devel] Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Stefan Hajnoczi
On Mon, Jan 31, 2011 at 12:18 PM, Jan Kiszka wrote: > On 2011-01-31 13:13, Stefan Hajnoczi wrote: >> On Mon, Jan 31, 2011 at 11:27 AM, Jan Kiszka wrote: >>> On 2011-01-31 11:03, Avi Kivity wrote: On 01/27/2011 04:33 PM, Jan Kiszka wrote: > Found by Stefan Hajnoczi: There is a race in kvm

Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Avi Kivity
On 01/31/2011 01:27 PM, Jan Kiszka wrote: On 2011-01-31 11:03, Avi Kivity wrote: > On 01/27/2011 04:33 PM, Jan Kiszka wrote: >> Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between >> checking for exit_request on vcpu entry and timer signals arriving >> before KVM starts to catch

Re: [Qemu-devel] Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Jan Kiszka
On 2011-01-31 13:13, Stefan Hajnoczi wrote: > On Mon, Jan 31, 2011 at 11:27 AM, Jan Kiszka wrote: >> On 2011-01-31 11:03, Avi Kivity wrote: >>> On 01/27/2011 04:33 PM, Jan Kiszka wrote: Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between checking for exit_request on vcpu en

Re: [Qemu-devel] Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Stefan Hajnoczi
On Mon, Jan 31, 2011 at 11:27 AM, Jan Kiszka wrote: > On 2011-01-31 11:03, Avi Kivity wrote: >> On 01/27/2011 04:33 PM, Jan Kiszka wrote: >>> Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between >>> checking for exit_request on vcpu entry and timer signals arriving >>> before KVM star

Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Jan Kiszka
On 2011-01-31 11:03, Avi Kivity wrote: > On 01/27/2011 04:33 PM, Jan Kiszka wrote: >> Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between >> checking for exit_request on vcpu entry and timer signals arriving >> before KVM starts to catch them. Plug it by blocking both timer related >>

Re: [PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-31 Thread Avi Kivity
On 01/27/2011 04:33 PM, Jan Kiszka wrote: Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between checking for exit_request on vcpu entry and timer signals arriving before KVM starts to catch them. Plug it by blocking both timer related signals also on !CONFIG_IOTHREAD and process those

[PATCH v3 14/22] kvm: Fix race between timer signals and vcpu entry under !IOTHREAD

2011-01-27 Thread Jan Kiszka
Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between checking for exit_request on vcpu entry and timer signals arriving before KVM starts to catch them. Plug it by blocking both timer related signals also on !CONFIG_IOTHREAD and process those via signalfd. As this fix depends on real