2011/12/15 Gleb Natapov <gleb@xxxxxxxxxx>: > On Thu, Dec 15, 2011 at 11:21:37AM +0800, Liu ping fan wrote: >> On Tue, Dec 13, 2011 at 7:36 PM, Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote: >> > On Mon, Dec 12, 2011 at 10:41:23AM +0800, Liu Ping Fan wrote: >> >> From: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> >> >> >> >> Currently, vcpu can be destructed only when kvm instance destroyed. >> >> Change this to vcpu's destruction taken when its refcnt is zero, >> >> and then vcpu MUST and CAN be destroyed before kvm's destroy. >> >> >> >> Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> >> >> --- >> >> arch/x86/kvm/i8254.c | 10 ++++-- >> >> arch/x86/kvm/i8259.c | 12 +++++-- >> >> arch/x86/kvm/mmu.c | 7 ++-- >> >> arch/x86/kvm/x86.c | 54 +++++++++++++++++++---------------- >> >> include/linux/kvm_host.h | 71 ++++++++++++++++++++++++++++++++++++++++++---- >> >> virt/kvm/irq_comm.c | 7 +++- >> >> virt/kvm/kvm_main.c | 62 +++++++++++++++++++++++++++++++++------ >> >> 7 files changed, 170 insertions(+), 53 deletions(-) >> > >> > This needs a full audit of paths that access vcpus. See for one example >> > bsp_vcpu pointer. >> > >> Yes, I had missed it and just paid attention to the access path to >> vcpu in kvm_lapic and the path used in async_pf. I will correct it >> later. >> BTW, I want to make it sure that because kvm_lapic will be destroyed >> before vcpu, so it is safe to bypass the access path there, and the >> situation is the same in async_pf for we have called >> kvm_clear_async_pf_completion_queue before zapping vcpu. Am I right? >> >> As to the scene like bsp_vcpu, I think that introducing refcount like >> in V2 can handle it easier. Please help to review these changes in V4 >> which I will send a little later. >> > Since bsp_vcpu pointer will never be released or re-assigned introducing > reference count to keep the pointer valid is not necessary. The counter > will never reach 0 and bsp vcpu will never be freed. Just disallow OK. And I have a question -- who will play the role to guard bsp_vcpu? kernel or qemu? Must I add something in kernel to protect the bsp_vcpu > removal of bsp_vcpu. Or better get rid of bsp_vcpu at all since its only > use is invalid anyway. > I will dig into it and see how to handle it. Thanks and regards, ping fan > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
