* [PATCH v3] kvm-vfio: do not use module_init
@ 2014-09-24 12:09 Paolo Bonzini
2014-09-24 12:14 ` Will Deacon
2014-09-24 15:41 ` Alex Williamson
0 siblings, 2 replies; 3+ messages in thread
From: Paolo Bonzini @ 2014-09-24 12:09 UTC (permalink / raw)
To: linux-kernel, kvm; +Cc: Will Deacon, Gleb Natapov, Alex Williamson
/me got confused between the kernel and QEMU. In the kernel, you can
only have one module_init function, and it will prevent unloading the
module unless you also have the corresponding module_exit function.
So, commit 80ce1639727e (KVM: VFIO: register kvm_device_ops dynamically,
2014-09-02) broke unloading of the kvm module, by adding a module_init
function and no module_exit.
Repair it by making kvm_vfio_ops_init weak, and checking it in
kvm_init.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alex Williamson <Alex.Williamson@redhat.com>
Fixes: 80ce1639727e9d38729c34f162378508c307ca25
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/kvm_main.c | 4 ++++
virt/kvm/vfio.c | 4 ++--
virt/kvm/vfio.h | 13 +++++++++++++
3 files changed, 19 insertions(+), 2 deletions(-)
create mode 100644 virt/kvm/vfio.h
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index db57363cc287..499db0977f3c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -57,6 +57,7 @@
#include "coalesced_mmio.h"
#include "async_pf.h"
+#include "vfio.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
@@ -3226,6 +3227,9 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
goto out_undebugfs;
}
+ r = kvm_vfio_ops_init();
+ WARN_ON(r);
+
return 0;
out_undebugfs:
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index bb11b36ee8a2..281e7cf2b8e5 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/vfio.h>
+#include "vfio.h"
struct kvm_vfio_group {
struct list_head node;
@@ -278,8 +279,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
return 0;
}
-static int __init kvm_vfio_ops_init(void)
+int kvm_vfio_ops_init(void)
{
return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
}
-module_init(kvm_vfio_ops_init);
diff --git a/virt/kvm/vfio.h b/virt/kvm/vfio.h
new file mode 100644
index 000000000000..92eac75d6b62
--- /dev/null
+++ b/virt/kvm/vfio.h
@@ -0,0 +1,13 @@
+#ifndef __KVM_VFIO_H
+#define __KVM_VFIO_H
+
+#ifdef CONFIG_KVM_VFIO
+int kvm_vfio_ops_init(void);
+#else
+static inline int kvm_vfio_ops_init(void)
+{
+ return 0;
+}
+#endif
+
+#endif
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3] kvm-vfio: do not use module_init
2014-09-24 12:09 [PATCH v3] kvm-vfio: do not use module_init Paolo Bonzini
@ 2014-09-24 12:14 ` Will Deacon
2014-09-24 15:41 ` Alex Williamson
1 sibling, 0 replies; 3+ messages in thread
From: Will Deacon @ 2014-09-24 12:14 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm, Gleb Natapov, Alex Williamson
On Wed, Sep 24, 2014 at 01:09:28PM +0100, Paolo Bonzini wrote:
> /me got confused between the kernel and QEMU. In the kernel, you can
> only have one module_init function, and it will prevent unloading the
> module unless you also have the corresponding module_exit function.
>
> So, commit 80ce1639727e (KVM: VFIO: register kvm_device_ops dynamically,
> 2014-09-02) broke unloading of the kvm module, by adding a module_init
> function and no module_exit.
>
> Repair it by making kvm_vfio_ops_init weak, and checking it in
> kvm_init.
>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Gleb Natapov <gleb@kernel.org>
> Cc: Alex Williamson <Alex.Williamson@redhat.com>
> Fixes: 80ce1639727e9d38729c34f162378508c307ca25
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> virt/kvm/kvm_main.c | 4 ++++
> virt/kvm/vfio.c | 4 ++--
> virt/kvm/vfio.h | 13 +++++++++++++
> 3 files changed, 19 insertions(+), 2 deletions(-)
> create mode 100644 virt/kvm/vfio.h
Looks good to me, thanks for fixing this:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index db57363cc287..499db0977f3c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -57,6 +57,7 @@
>
> #include "coalesced_mmio.h"
> #include "async_pf.h"
> +#include "vfio.h"
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/kvm.h>
> @@ -3226,6 +3227,9 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
> goto out_undebugfs;
> }
>
> + r = kvm_vfio_ops_init();
> + WARN_ON(r);
> +
> return 0;
>
> out_undebugfs:
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index bb11b36ee8a2..281e7cf2b8e5 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -18,6 +18,7 @@
> #include <linux/slab.h>
> #include <linux/uaccess.h>
> #include <linux/vfio.h>
> +#include "vfio.h"
>
> struct kvm_vfio_group {
> struct list_head node;
> @@ -278,8 +279,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
> return 0;
> }
>
> -static int __init kvm_vfio_ops_init(void)
> +int kvm_vfio_ops_init(void)
> {
> return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
> }
> -module_init(kvm_vfio_ops_init);
> diff --git a/virt/kvm/vfio.h b/virt/kvm/vfio.h
> new file mode 100644
> index 000000000000..92eac75d6b62
> --- /dev/null
> +++ b/virt/kvm/vfio.h
> @@ -0,0 +1,13 @@
> +#ifndef __KVM_VFIO_H
> +#define __KVM_VFIO_H
> +
> +#ifdef CONFIG_KVM_VFIO
> +int kvm_vfio_ops_init(void);
> +#else
> +static inline int kvm_vfio_ops_init(void)
> +{
> + return 0;
> +}
> +#endif
> +
> +#endif
> --
> 1.8.3.1
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] kvm-vfio: do not use module_init
2014-09-24 12:09 [PATCH v3] kvm-vfio: do not use module_init Paolo Bonzini
2014-09-24 12:14 ` Will Deacon
@ 2014-09-24 15:41 ` Alex Williamson
1 sibling, 0 replies; 3+ messages in thread
From: Alex Williamson @ 2014-09-24 15:41 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm, Will Deacon, Gleb Natapov
On Wed, 2014-09-24 at 14:09 +0200, Paolo Bonzini wrote:
> /me got confused between the kernel and QEMU. In the kernel, you can
> only have one module_init function, and it will prevent unloading the
> module unless you also have the corresponding module_exit function.
>
> So, commit 80ce1639727e (KVM: VFIO: register kvm_device_ops dynamically,
> 2014-09-02) broke unloading of the kvm module, by adding a module_init
> function and no module_exit.
>
> Repair it by making kvm_vfio_ops_init weak, and checking it in
> kvm_init.
>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Gleb Natapov <gleb@kernel.org>
> Cc: Alex Williamson <Alex.Williamson@redhat.com>
> Fixes: 80ce1639727e9d38729c34f162378508c307ca25
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> virt/kvm/kvm_main.c | 4 ++++
> virt/kvm/vfio.c | 4 ++--
> virt/kvm/vfio.h | 13 +++++++++++++
> 3 files changed, 19 insertions(+), 2 deletions(-)
> create mode 100644 virt/kvm/vfio.h
Thanks Paolo
Acked-by: Alex Williamson <alex.williamson@redhat.com>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index db57363cc287..499db0977f3c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -57,6 +57,7 @@
>
> #include "coalesced_mmio.h"
> #include "async_pf.h"
> +#include "vfio.h"
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/kvm.h>
> @@ -3226,6 +3227,9 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
> goto out_undebugfs;
> }
>
> + r = kvm_vfio_ops_init();
> + WARN_ON(r);
> +
> return 0;
>
> out_undebugfs:
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index bb11b36ee8a2..281e7cf2b8e5 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -18,6 +18,7 @@
> #include <linux/slab.h>
> #include <linux/uaccess.h>
> #include <linux/vfio.h>
> +#include "vfio.h"
>
> struct kvm_vfio_group {
> struct list_head node;
> @@ -278,8 +279,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
> return 0;
> }
>
> -static int __init kvm_vfio_ops_init(void)
> +int kvm_vfio_ops_init(void)
> {
> return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO);
> }
> -module_init(kvm_vfio_ops_init);
> diff --git a/virt/kvm/vfio.h b/virt/kvm/vfio.h
> new file mode 100644
> index 000000000000..92eac75d6b62
> --- /dev/null
> +++ b/virt/kvm/vfio.h
> @@ -0,0 +1,13 @@
> +#ifndef __KVM_VFIO_H
> +#define __KVM_VFIO_H
> +
> +#ifdef CONFIG_KVM_VFIO
> +int kvm_vfio_ops_init(void);
> +#else
> +static inline int kvm_vfio_ops_init(void)
> +{
> + return 0;
> +}
> +#endif
> +
> +#endif
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-09-24 12:14 ` Will Deacon
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