* [PATCH] KVM: x86: should release vcpu when closing vcpu fd
@ 2013-08-28 8:08 Chen Fan
2013-08-28 8:21 ` Gleb Natapov
0 siblings, 1 reply; 4+ messages in thread
From: Chen Fan @ 2013-08-28 8:08 UTC (permalink / raw)
To: kvm
If we want to remove a vcpu from vm, we should not be only to
put kvm, we need to decrease online vcpus and free struct kvm_vcpu
when closing a vcpu file descriptor.
Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
---
arch/x86/kvm/x86.c | 14 ++++++++++++++
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 4 +++-
3 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d21bce5..3370de1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6904,6 +6904,20 @@ static void kvm_free_vcpus(struct kvm *kvm)
mutex_unlock(&kvm->lock);
}
+void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu)
+{
+ struct kvm *kvm = vcpu->kvm;
+
+ mutex_lock(&kvm->lock);
+ atomic_dec(&kvm->online_vcpus);
+ kvm->vcpus[atomic_read(&kvm->online_vcpus)] = NULL;
+ mutex_unlock(&kvm->lock);
+
+ kvm_clear_async_pf_completion_queue(vcpu);
+ kvm_unload_vcpu_mmu(vcpu);
+ kvm_arch_vcpu_free(vcpu);
+}
+
void kvm_arch_sync_events(struct kvm *kvm)
{
kvm_free_all_assigned_devices(kvm);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a63d83e..e0811f97 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -631,6 +631,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id);
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu);
int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
+void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu);
int kvm_arch_hardware_enable(void *garbage);
void kvm_arch_hardware_disable(void *garbage);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1580dd4..442014b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1873,8 +1873,10 @@ static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
static int kvm_vcpu_release(struct inode *inode, struct file *filp)
{
struct kvm_vcpu *vcpu = filp->private_data;
+ struct kvm *kvm = vcpu->kvm;
- kvm_put_kvm(vcpu->kvm);
+ kvm_arch_vcpu_release(vcpu);
+ kvm_put_kvm(kvm);
return 0;
}
--
1.8.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] KVM: x86: should release vcpu when closing vcpu fd
2013-08-28 8:08 [PATCH] KVM: x86: should release vcpu when closing vcpu fd Chen Fan
@ 2013-08-28 8:21 ` Gleb Natapov
2013-08-29 3:06 ` chenfan
0 siblings, 1 reply; 4+ messages in thread
From: Gleb Natapov @ 2013-08-28 8:21 UTC (permalink / raw)
To: Chen Fan; +Cc: kvm
On Wed, Aug 28, 2013 at 04:08:10PM +0800, Chen Fan wrote:
> If we want to remove a vcpu from vm, we should not be only to
> put kvm, we need to decrease online vcpus and free struct kvm_vcpu
> when closing a vcpu file descriptor.
>
It much more complicated that what you do here. kvm->vcpus[] is accessed
without locking and kvm->online_vcpus is assumed to be greater than max
occupied index in kvm->vcpus[]. Attempt where made to make it possible
to destroy individual vcpus separately from destroying VM before, but
they were unsuccessful thus far.
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
> arch/x86/kvm/x86.c | 14 ++++++++++++++
> include/linux/kvm_host.h | 1 +
> virt/kvm/kvm_main.c | 4 +++-
> 3 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d21bce5..3370de1 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6904,6 +6904,20 @@ static void kvm_free_vcpus(struct kvm *kvm)
> mutex_unlock(&kvm->lock);
> }
>
> +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu)
> +{
> + struct kvm *kvm = vcpu->kvm;
> +
> + mutex_lock(&kvm->lock);
> + atomic_dec(&kvm->online_vcpus);
> + kvm->vcpus[atomic_read(&kvm->online_vcpus)] = NULL;
> + mutex_unlock(&kvm->lock);
> +
> + kvm_clear_async_pf_completion_queue(vcpu);
> + kvm_unload_vcpu_mmu(vcpu);
> + kvm_arch_vcpu_free(vcpu);
> +}
> +
> void kvm_arch_sync_events(struct kvm *kvm)
> {
> kvm_free_all_assigned_devices(kvm);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index a63d83e..e0811f97 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -631,6 +631,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id);
> int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu);
> int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
> void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
> +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu);
>
> int kvm_arch_hardware_enable(void *garbage);
> void kvm_arch_hardware_disable(void *garbage);
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 1580dd4..442014b 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1873,8 +1873,10 @@ static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
> static int kvm_vcpu_release(struct inode *inode, struct file *filp)
> {
> struct kvm_vcpu *vcpu = filp->private_data;
> + struct kvm *kvm = vcpu->kvm;
>
> - kvm_put_kvm(vcpu->kvm);
> + kvm_arch_vcpu_release(vcpu);
> + kvm_put_kvm(kvm);
> return 0;
> }
>
> --
> 1.8.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Gleb.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] KVM: x86: should release vcpu when closing vcpu fd
2013-08-28 8:21 ` Gleb Natapov
@ 2013-08-29 3:06 ` chenfan
2013-08-29 3:20 ` Gleb Natapov
0 siblings, 1 reply; 4+ messages in thread
From: chenfan @ 2013-08-29 3:06 UTC (permalink / raw)
To: Gleb Natapov; +Cc: kvm
On Wed, 2013-08-28 at 11:21 +0300, Gleb Natapov wrote:
> On Wed, Aug 28, 2013 at 04:08:10PM +0800, Chen Fan wrote:
> > If we want to remove a vcpu from vm, we should not be only to
> > put kvm, we need to decrease online vcpus and free struct kvm_vcpu
> > when closing a vcpu file descriptor.
> >
> It much more complicated that what you do here. kvm->vcpus[] is accessed
> without locking and kvm->online_vcpus is assumed to be greater than max
> occupied index in kvm->vcpus[]. Attempt where made to make it possible
> to destroy individual vcpus separately from destroying VM before, but
> they were unsuccessful thus far.
>
Oh, the motivation of this patch is for QEMU for implementing cpu
hot-remove, I want to remove the vcpu from KVM after QEMU closing the
kvm_fd. there I need some advice for this feature. if this patch is not
comprehensive enough，I want to know the reasons for a more detailed.
Could you tell me?
Thanks,
Chen
> > Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> > ---
> > arch/x86/kvm/x86.c | 14 ++++++++++++++
> > include/linux/kvm_host.h | 1 +
> > virt/kvm/kvm_main.c | 4 +++-
> > 3 files changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index d21bce5..3370de1 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -6904,6 +6904,20 @@ static void kvm_free_vcpus(struct kvm *kvm)
> > mutex_unlock(&kvm->lock);
> > }
> >
> > +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu)
> > +{
> > + struct kvm *kvm = vcpu->kvm;
> > +
> > + mutex_lock(&kvm->lock);
> > + atomic_dec(&kvm->online_vcpus);
> > + kvm->vcpus[atomic_read(&kvm->online_vcpus)] = NULL;
> > + mutex_unlock(&kvm->lock);
> > +
> > + kvm_clear_async_pf_completion_queue(vcpu);
> > + kvm_unload_vcpu_mmu(vcpu);
> > + kvm_arch_vcpu_free(vcpu);
> > +}
> > +
> > void kvm_arch_sync_events(struct kvm *kvm)
> > {
> > kvm_free_all_assigned_devices(kvm);
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index a63d83e..e0811f97 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -631,6 +631,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id);
> > int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu);
> > int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
> > void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
> > +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu);
> >
> > int kvm_arch_hardware_enable(void *garbage);
> > void kvm_arch_hardware_disable(void *garbage);
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index 1580dd4..442014b 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -1873,8 +1873,10 @@ static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
> > static int kvm_vcpu_release(struct inode *inode, struct file *filp)
> > {
> > struct kvm_vcpu *vcpu = filp->private_data;
> > + struct kvm *kvm = vcpu->kvm;
> >
> > - kvm_put_kvm(vcpu->kvm);
> > + kvm_arch_vcpu_release(vcpu);
> > + kvm_put_kvm(kvm);
> > return 0;
> > }
> >
> > --
> > 1.8.1.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> --
> Gleb.
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] KVM: x86: should release vcpu when closing vcpu fd
2013-08-29 3:06 ` chenfan
@ 2013-08-29 3:20 ` Gleb Natapov
0 siblings, 0 replies; 4+ messages in thread
From: Gleb Natapov @ 2013-08-29 3:20 UTC (permalink / raw)
To: chenfan; +Cc: kvm
On Thu, Aug 29, 2013 at 11:06:47AM +0800, chenfan wrote:
> On Wed, 2013-08-28 at 11:21 +0300, Gleb Natapov wrote:
> > On Wed, Aug 28, 2013 at 04:08:10PM +0800, Chen Fan wrote:
> > > If we want to remove a vcpu from vm, we should not be only to
> > > put kvm, we need to decrease online vcpus and free struct kvm_vcpu
> > > when closing a vcpu file descriptor.
> > >
> > It much more complicated that what you do here. kvm->vcpus[] is accessed
> > without locking and kvm->online_vcpus is assumed to be greater than max
> > occupied index in kvm->vcpus[]. Attempt where made to make it possible
> > to destroy individual vcpus separately from destroying VM before, but
> > they were unsuccessful thus far.
> >
> Oh, the motivation of this patch is for QEMU for implementing cpu
> hot-remove, I want to remove the vcpu from KVM after QEMU closing the
> kvm_fd. there I need some advice for this feature. if this patch is not
> comprehensive enough，I want to know the reasons for a more detailed.
> Could you tell me?
>
I told you above.
> Thanks,
> Chen
>
> > > Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> > > ---
> > > arch/x86/kvm/x86.c | 14 ++++++++++++++
> > > include/linux/kvm_host.h | 1 +
> > > virt/kvm/kvm_main.c | 4 +++-
> > > 3 files changed, 18 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > > index d21bce5..3370de1 100644
> > > --- a/arch/x86/kvm/x86.c
> > > +++ b/arch/x86/kvm/x86.c
> > > @@ -6904,6 +6904,20 @@ static void kvm_free_vcpus(struct kvm *kvm)
> > > mutex_unlock(&kvm->lock);
> > > }
> > >
> > > +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu)
> > > +{
> > > + struct kvm *kvm = vcpu->kvm;
> > > +
> > > + mutex_lock(&kvm->lock);
> > > + atomic_dec(&kvm->online_vcpus);
> > > + kvm->vcpus[atomic_read(&kvm->online_vcpus)] = NULL;
> > > + mutex_unlock(&kvm->lock);
> > > +
> > > + kvm_clear_async_pf_completion_queue(vcpu);
> > > + kvm_unload_vcpu_mmu(vcpu);
> > > + kvm_arch_vcpu_free(vcpu);
> > > +}
> > > +
> > > void kvm_arch_sync_events(struct kvm *kvm)
> > > {
> > > kvm_free_all_assigned_devices(kvm);
> > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > > index a63d83e..e0811f97 100644
> > > --- a/include/linux/kvm_host.h
> > > +++ b/include/linux/kvm_host.h
> > > @@ -631,6 +631,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id);
> > > int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu);
> > > int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
> > > void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
> > > +void kvm_arch_vcpu_release(struct kvm_vcpu *vcpu);
> > >
> > > int kvm_arch_hardware_enable(void *garbage);
> > > void kvm_arch_hardware_disable(void *garbage);
> > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > > index 1580dd4..442014b 100644
> > > --- a/virt/kvm/kvm_main.c
> > > +++ b/virt/kvm/kvm_main.c
> > > @@ -1873,8 +1873,10 @@ static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
> > > static int kvm_vcpu_release(struct inode *inode, struct file *filp)
> > > {
> > > struct kvm_vcpu *vcpu = filp->private_data;
> > > + struct kvm *kvm = vcpu->kvm;
> > >
> > > - kvm_put_kvm(vcpu->kvm);
> > > + kvm_arch_vcpu_release(vcpu);
> > > + kvm_put_kvm(kvm);
> > > return 0;
> > > }
> > >
> > > --
> > > 1.8.1.4
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> > --
> > Gleb.
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Gleb.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-08-29 3:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2013-08-28 8:08 [PATCH] KVM: x86: should release vcpu when closing vcpu fd Chen Fan
2013-08-28 8:21 ` Gleb Natapov
2013-08-29 3:06 ` chenfan
2013-08-29 3:20 ` Gleb Natapov
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