[RFC PATCH] PPC: KVM: vfio kvm device: support spapr tce

This is a very rough change set required for ppc64 to use this KVM device.

vfio_rm.c is a piece of code which is going to be called from the realmode (MMU off),
and I will put everything spapr-related under #ifdef CONFIG_SPAPR_TCE_IOMMU,
it is just friday and I have to run :)

This is an RFC but it works.

Signed-off-by: Alexey Kardashevskiy <redacted>
---
 arch/powerpc/kvm/Kconfig  |  1 +
 arch/powerpc/kvm/Makefile |  4 ++++
 include/linux/kvm_host.h  |  8 ++++---
 include/linux/vfio.h      |  3 +++
 include/uapi/linux/kvm.h  |  1 +
 virt/kvm/vfio.c           | 46 ++++++++++++++++++++++++++++++++++++++++
 virt/kvm/vfio_rm.c        | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 114 insertions(+), 3 deletions(-)
 create mode 100644 virt/kvm/vfio_rm.c

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 61b3535..d1b7f64 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig

@@ -60,6 +60,7 @@ config KVM_BOOK3S_64
 	select KVM_BOOK3S_64_HANDLER
 	select KVM
 	select SPAPR_TCE_IOMMU
+	select KVM_VFIO
 	---help---
 	  Support running unmodified book3s_64 and book3s_32 guest kernels
 	  in virtual machines on book3s_64 host processors.

diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 6646c95..fc2878b 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile

@@ -55,6 +55,8 @@ kvm-objs-$(CONFIG_KVM_E500MC) := $(kvm-e500mc-objs)
 
 kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_PR) := \
 	$(KVM)/coalesced_mmio.o \
+	$(KVM)/vfio.o \
+	$(KVM)/vfio_rm.o \
 	fpu.o \
 	book3s_paired_singles.o \
 	book3s_pr.o \

@@ -76,6 +78,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
 kvm-book3s_64-builtin-xics-objs-$(CONFIG_KVM_XICS) := \
 	book3s_hv_rm_xics.o
 kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
+	$(KVM)/vfio_rm.o \
 	book3s_hv_rmhandlers.o \
 	book3s_hv_rm_mmu.o \
 	book3s_64_vio_hv.o \

@@ -89,6 +92,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_XICS) += \
 
 kvm-book3s_64-module-objs := \
 	$(KVM)/kvm_main.o \
+	$(KVM)/vfio.o \
 	$(KVM)/eventfd.o \
 	powerpc.o \
 	emulate.o \

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ad2b581..43c0290 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -407,6 +407,8 @@ struct kvm {
 #endif
 	long tlbs_dirty;
 	struct list_head devices;
+
+	struct kvm_vfio *vfio;
 };
 
 #define kvm_err(fmt, ...) \

@@ -677,15 +679,15 @@ void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
 void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
 bool kvm_arch_has_noncoherent_dma(struct kvm *kvm);
 #else
-static inline void kvm_arch_register_noncoherent_dma(void)
+static inline void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline void kvm_arch_unregister_noncoherent_dma(void)
+static inline void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline bool kvm_arch_has_noncoherent_dma(void)
+static inline bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 {
 	return false;
 }

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 24579a0..681e19b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h

@@ -97,4 +97,7 @@ extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
 
+extern struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm,
+		unsigned long liobn);
+
 #endif /* VFIO_H */

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7c1a349..a74ad16 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h

@@ -847,6 +847,7 @@ struct kvm_device_attr {
 #define  KVM_DEV_VFIO_GROUP			1
 #define   KVM_DEV_VFIO_GROUP_ADD			1
 #define   KVM_DEV_VFIO_GROUP_DEL			2
+#define  KVM_DEV_VFIO_SPAPR_TCE_LIOBN		2
 
 /*
  * ioctls for VM fds

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 2e336a7..39dea9f 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c

@@ -22,6 +22,7 @@
 struct kvm_vfio_group {
 	struct list_head node;
 	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */
 };
 
 struct kvm_vfio {

@@ -188,12 +189,52 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 	return -ENXIO;
 }
 
+static int kvm_vfio_set_spapr_tce_liobn(struct kvm_device *dev,
+		long attr, u64 arg)
+{
+	struct kvm_vfio *kv = dev->private;
+	struct vfio_group *vfio_group;
+	struct kvm_vfio_group *kvg;
+	void __user *argp = (void __user *)arg;
+	struct fd f;
+	int32_t fd;
+	uint64_t liobn = attr;
+
+	if (get_user(fd, (int32_t __user *)argp))
+		return -EFAULT;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	vfio_group = kvm_vfio_group_get_external_user(f.file);
+	fdput(f);
+
+	list_for_each_entry(kvg, &kv->group_list, node) {
+		if (kvg->vfio_group == vfio_group) {
+			WARN_ON(kvg->liobn);
+			kvg->liobn = liobn;
+			kvm_vfio_group_put_external_user(vfio_group);
+			return 0;
+		}
+	}
+
+	kvm_vfio_group_put_external_user(vfio_group);
+
+	return -ENXIO;
+}
+
 static int kvm_vfio_set_attr(struct kvm_device *dev,
 			     struct kvm_device_attr *attr)
 {
 	switch (attr->group) {
 	case KVM_DEV_VFIO_GROUP:
 		return kvm_vfio_set_group(dev, attr->attr, attr->addr);
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return kvm_vfio_set_spapr_tce_liobn(dev, attr->attr,
+				attr->addr);
+#endif
 	}
 
 	return -ENXIO;

@@ -211,6 +252,10 @@ static int kvm_vfio_has_attr(struct kvm_device *dev,
 		}
 
 		break;
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return 0;
+#endif
 	}
 
 	return -ENXIO;

@@ -250,6 +295,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
 	mutex_init(&kv->lock);
 
 	dev->private = kv;
+	dev->kvm->vfio = kv;
 
 	return 0;
 }

diff --git a/virt/kvm/vfio_rm.c b/virt/kvm/vfio_rm.c
new file mode 100644
index 0000000..ee9fd96
--- /dev/null
+++ b/virt/kvm/vfio_rm.c

@@ -0,0 +1,54 @@
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/kvm_host.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+
+struct kvm_vfio_group {
+	struct list_head node;
+	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */
+};
+
+struct kvm_vfio {
+	struct list_head group_list;
+	struct mutex lock;
+	bool noncoherent;
+};
+
+struct vfio_group {
+	struct kref			kref;
+	int				minor;
+	atomic_t			container_users;
+	struct iommu_group		*iommu_group;
+	struct vfio_container		*container;
+	struct list_head		device_list;
+	struct mutex			device_lock;
+	struct device			*dev;
+	struct notifier_block		nb;
+	struct list_head		vfio_next;
+	struct list_head		container_next;
+	atomic_t			opened;
+};
+
+struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm, unsigned long liobn)
+{
+	struct kvm_vfio_group *kvg;
+
+	if (!kvm->vfio)
+		return NULL;
+
+	list_for_each_entry(kvg, &kvm->vfio->group_list, node) {
+		if (kvg->liobn == liobn)
+			return kvg->vfio_group->iommu_group;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(vfio_find_group_by_liobn);
+
+

-- 
1.8.4.rc4

On Fri, 2013-10-04 at 22:24 +1000, Alexey Kardashevskiy wrote:

<cringe> can't this be on kvm->arch?

Will fix in my series.

Wrong header file.

Perhaps an arch pointer or at least a union.

Users shouldn't be able to trigger WARN_ON so easily, return -EBUSY,
allow it to be unset and re-set, or just allow the overwrite.

You're kidding, right?  These are intentionally private data structures
that are blatantly copied so that you can extract what you want.  NACK.
The iommu_group is available off struct device, do you even need vfio or
this kvm-vfio device to get from liobn to iommu_group?  Thanks,

Alex

On 05.10.2013 2:05, Alex Williamson wrote:

On Fri, 2013-10-04 at 22:24 +1000, Alexey Kardashevskiy wrote:

quoted

This is a very rough change set required for ppc64 to use this KVM device.

vfio_rm.c is a piece of code which is going to be called from the realmode (MMU off),
and I will put everything spapr-related under #ifdef CONFIG_SPAPR_TCE_IOMMU,
it is just friday and I have to run :)

This is an RFC but it works.

Signed-off-by: Alexey Kardashevskiy <redacted>
---
 arch/powerpc/kvm/Kconfig  |  1 +
 arch/powerpc/kvm/Makefile |  4 ++++
 include/linux/kvm_host.h  |  8 ++++---
 include/linux/vfio.h      |  3 +++
 include/uapi/linux/kvm.h  |  1 +
 virt/kvm/vfio.c           | 46 ++++++++++++++++++++++++++++++++++++++++
 virt/kvm/vfio_rm.c        | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 114 insertions(+), 3 deletions(-)
 create mode 100644 virt/kvm/vfio_rm.c

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 61b3535..d1b7f64 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig

@@ -60,6 +60,7 @@ config KVM_BOOK3S_64
 	select KVM_BOOK3S_64_HANDLER
 	select KVM
 	select SPAPR_TCE_IOMMU
+	select KVM_VFIO
 	---help---
 	  Support running unmodified book3s_64 and book3s_32 guest kernels
 	  in virtual machines on book3s_64 host processors.

diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 6646c95..fc2878b 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile

@@ -55,6 +55,8 @@ kvm-objs-$(CONFIG_KVM_E500MC) := $(kvm-e500mc-objs)
 
 kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_PR) := \
 	$(KVM)/coalesced_mmio.o \
+	$(KVM)/vfio.o \
+	$(KVM)/vfio_rm.o \
 	fpu.o \
 	book3s_paired_singles.o \
 	book3s_pr.o \

@@ -76,6 +78,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
 kvm-book3s_64-builtin-xics-objs-$(CONFIG_KVM_XICS) := \
 	book3s_hv_rm_xics.o
 kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
+	$(KVM)/vfio_rm.o \
 	book3s_hv_rmhandlers.o \
 	book3s_hv_rm_mmu.o \
 	book3s_64_vio_hv.o \

@@ -89,6 +92,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_XICS) += \
 
 kvm-book3s_64-module-objs := \
 	$(KVM)/kvm_main.o \
+	$(KVM)/vfio.o \
 	$(KVM)/eventfd.o \
 	powerpc.o \
 	emulate.o \

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ad2b581..43c0290 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -407,6 +407,8 @@ struct kvm {
 #endif
 	long tlbs_dirty;
 	struct list_head devices;
+
+	struct kvm_vfio *vfio;

<cringe> can't this be on kvm->arch?

It can, I just thought since it is valid for more than just one
platform, it can go here.

quoted

 };
 
 #define kvm_err(fmt, ...) \

@@ -677,15 +679,15 @@ void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
 void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
 bool kvm_arch_has_noncoherent_dma(struct kvm *kvm);
 #else
-static inline void kvm_arch_register_noncoherent_dma(void)
+static inline void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline void kvm_arch_unregister_noncoherent_dma(void)
+static inline void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline bool kvm_arch_has_noncoherent_dma(void)
+static inline bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 {
 	return false;
 }

Will fix in my series.

quoted

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 24579a0..681e19b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h

@@ -97,4 +97,7 @@ extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
 
+extern struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm,
+		unsigned long liobn);
+

Wrong header file.

quoted

 #endif /* VFIO_H */

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7c1a349..a74ad16 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h

@@ -847,6 +847,7 @@ struct kvm_device_attr {
 #define  KVM_DEV_VFIO_GROUP			1
 #define   KVM_DEV_VFIO_GROUP_ADD			1
 #define   KVM_DEV_VFIO_GROUP_DEL			2
+#define  KVM_DEV_VFIO_SPAPR_TCE_LIOBN		2
 
 /*
  * ioctls for VM fds

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 2e336a7..39dea9f 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c

@@ -22,6 +22,7 @@
 struct kvm_vfio_group {
 	struct list_head node;
 	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */

Perhaps an arch pointer or at least a union.

quoted

 };
 
 struct kvm_vfio {

@@ -188,12 +189,52 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 	return -ENXIO;
 }
 
+static int kvm_vfio_set_spapr_tce_liobn(struct kvm_device *dev,
+		long attr, u64 arg)
+{
+	struct kvm_vfio *kv = dev->private;
+	struct vfio_group *vfio_group;
+	struct kvm_vfio_group *kvg;
+	void __user *argp = (void __user *)arg;
+	struct fd f;
+	int32_t fd;
+	uint64_t liobn = attr;
+
+	if (get_user(fd, (int32_t __user *)argp))
+		return -EFAULT;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	vfio_group = kvm_vfio_group_get_external_user(f.file);
+	fdput(f);
+
+	list_for_each_entry(kvg, &kv->group_list, node) {
+		if (kvg->vfio_group == vfio_group) {
+			WARN_ON(kvg->liobn);

Users shouldn't be able to trigger WARN_ON so easily, return -EBUSY,
allow it to be unset and re-set, or just allow the overwrite.

quoted

+			kvg->liobn = liobn;
+			kvm_vfio_group_put_external_user(vfio_group);
+			return 0;
+		}
+	}
+
+	kvm_vfio_group_put_external_user(vfio_group);
+
+	return -ENXIO;
+}
+
 static int kvm_vfio_set_attr(struct kvm_device *dev,
 			     struct kvm_device_attr *attr)
 {
 	switch (attr->group) {
 	case KVM_DEV_VFIO_GROUP:
 		return kvm_vfio_set_group(dev, attr->attr, attr->addr);
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return kvm_vfio_set_spapr_tce_liobn(dev, attr->attr,
+				attr->addr);
+#endif
 	}
 
 	return -ENXIO;

@@ -211,6 +252,10 @@ static int kvm_vfio_has_attr(struct kvm_device *dev,
 		}
 
 		break;
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return 0;
+#endif
 	}
 
 	return -ENXIO;

@@ -250,6 +295,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
 	mutex_init(&kv->lock);
 
 	dev->private = kv;
+	dev->kvm->vfio = kv;
 
 	return 0;
 }

diff --git a/virt/kvm/vfio_rm.c b/virt/kvm/vfio_rm.c
new file mode 100644
index 0000000..ee9fd96
--- /dev/null
+++ b/virt/kvm/vfio_rm.c

@@ -0,0 +1,54 @@
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/kvm_host.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+
+struct kvm_vfio_group {
+	struct list_head node;
+	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */
+};
+
+struct kvm_vfio {
+	struct list_head group_list;
+	struct mutex lock;
+	bool noncoherent;
+};
+
+struct vfio_group {
+	struct kref			kref;
+	int				minor;
+	atomic_t			container_users;
+	struct iommu_group		*iommu_group;
+	struct vfio_container		*container;
+	struct list_head		device_list;
+	struct mutex			device_lock;
+	struct device			*dev;
+	struct notifier_block		nb;
+	struct list_head		vfio_next;
+	struct list_head		container_next;
+	atomic_t			opened;
+};
+
+struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm, unsigned long liobn)
+{
+	struct kvm_vfio_group *kvg;
+
+	if (!kvm->vfio)
+		return NULL;
+
+	list_for_each_entry(kvg, &kvm->vfio->group_list, node) {
+		if (kvg->liobn == liobn)
+			return kvg->vfio_group->iommu_group;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(vfio_find_group_by_liobn);
+
+

You're kidding, right?  These are intentionally private data structures
that are blatantly copied so that you can extract what you want.  NACK.
The iommu_group is available off struct device, do you even need vfio or
this kvm-vfio device to get from liobn to iommu_group?  Thanks,

This is an RFC. I am not saying this is what can go to upstream or
anything. I am not kidding (why everyone assumes that?), I am showing
what API I would like to have in the VFIO KVM device. I need the way to
get iommu_table (which is in a private data of iommu_group) by LIOBN and
the VFIO KVM device is the _only_ entity which will know about this
connection (LIOBN is made up by the qemu and told to the guest) and it
cannot go to the kvm.ko - and the patch like this is the best way to
show it as my english obviously sucks.



-- 
With best regards

Alexey Kardashevskiy -- icq: 52150396

On 10/05/2013 11:52 AM, Alexey Kardashevskiy wrote:

On 05.10.2013 2:05, Alex Williamson wrote:

quoted

On Fri, 2013-10-04 at 22:24 +1000, Alexey Kardashevskiy wrote:

quoted

This is a very rough change set required for ppc64 to use this KVM device.

vfio_rm.c is a piece of code which is going to be called from the realmode (MMU off),
and I will put everything spapr-related under #ifdef CONFIG_SPAPR_TCE_IOMMU,
it is just friday and I have to run :)

This is an RFC but it works.

Signed-off-by: Alexey Kardashevskiy <redacted>
---
 arch/powerpc/kvm/Kconfig  |  1 +
 arch/powerpc/kvm/Makefile |  4 ++++
 include/linux/kvm_host.h  |  8 ++++---
 include/linux/vfio.h      |  3 +++
 include/uapi/linux/kvm.h  |  1 +
 virt/kvm/vfio.c           | 46 ++++++++++++++++++++++++++++++++++++++++
 virt/kvm/vfio_rm.c        | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 114 insertions(+), 3 deletions(-)
 create mode 100644 virt/kvm/vfio_rm.c

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 61b3535..d1b7f64 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig

@@ -60,6 +60,7 @@ config KVM_BOOK3S_64
 	select KVM_BOOK3S_64_HANDLER
 	select KVM
 	select SPAPR_TCE_IOMMU
+	select KVM_VFIO
 	---help---
 	  Support running unmodified book3s_64 and book3s_32 guest kernels
 	  in virtual machines on book3s_64 host processors.

diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 6646c95..fc2878b 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile

@@ -55,6 +55,8 @@ kvm-objs-$(CONFIG_KVM_E500MC) := $(kvm-e500mc-objs)
 
 kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_PR) := \
 	$(KVM)/coalesced_mmio.o \
+	$(KVM)/vfio.o \
+	$(KVM)/vfio_rm.o \
 	fpu.o \
 	book3s_paired_singles.o \
 	book3s_pr.o \

@@ -76,6 +78,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
 kvm-book3s_64-builtin-xics-objs-$(CONFIG_KVM_XICS) := \
 	book3s_hv_rm_xics.o
 kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \
+	$(KVM)/vfio_rm.o \
 	book3s_hv_rmhandlers.o \
 	book3s_hv_rm_mmu.o \
 	book3s_64_vio_hv.o \

@@ -89,6 +92,7 @@ kvm-book3s_64-objs-$(CONFIG_KVM_XICS) += \
 
 kvm-book3s_64-module-objs := \
 	$(KVM)/kvm_main.o \
+	$(KVM)/vfio.o \
 	$(KVM)/eventfd.o \
 	powerpc.o \
 	emulate.o \

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ad2b581..43c0290 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -407,6 +407,8 @@ struct kvm {
 #endif
 	long tlbs_dirty;
 	struct list_head devices;
+
+	struct kvm_vfio *vfio;

<cringe> can't this be on kvm->arch?

It can, I just thought since it is valid for more than just one
platform, it can go here.

quoted

quoted

 };
 
 #define kvm_err(fmt, ...) \

@@ -677,15 +679,15 @@ void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
 void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
 bool kvm_arch_has_noncoherent_dma(struct kvm *kvm);
 #else
-static inline void kvm_arch_register_noncoherent_dma(void)
+static inline void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline void kvm_arch_unregister_noncoherent_dma(void)
+static inline void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm)
 {
 }
 
-static inline bool kvm_arch_has_noncoherent_dma(void)
+static inline bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 {
 	return false;
 }

Will fix in my series.

quoted

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 24579a0..681e19b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h

@@ -97,4 +97,7 @@ extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
 
+extern struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm,
+		unsigned long liobn);
+

Wrong header file.

btw there are two - uapi/linux/vfio.h and linux/vfio.h. The external user
API is in linux/vfio.h but my change should go to uapi/linux/vfio.h, is
that correct? Or we need a third header? Just asking, no kidding, no arguing :)

quoted

quoted

 #endif /* VFIO_H */

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7c1a349..a74ad16 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h

@@ -847,6 +847,7 @@ struct kvm_device_attr {
 #define  KVM_DEV_VFIO_GROUP			1
 #define   KVM_DEV_VFIO_GROUP_ADD			1
 #define   KVM_DEV_VFIO_GROUP_DEL			2
+#define  KVM_DEV_VFIO_SPAPR_TCE_LIOBN		2
 
 /*
  * ioctls for VM fds

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 2e336a7..39dea9f 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c

@@ -22,6 +22,7 @@
 struct kvm_vfio_group {
 	struct list_head node;
 	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */

Perhaps an arch pointer or at least a union.

quoted

 };
 
 struct kvm_vfio {

@@ -188,12 +189,52 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 	return -ENXIO;
 }
 
+static int kvm_vfio_set_spapr_tce_liobn(struct kvm_device *dev,
+		long attr, u64 arg)
+{
+	struct kvm_vfio *kv = dev->private;
+	struct vfio_group *vfio_group;
+	struct kvm_vfio_group *kvg;
+	void __user *argp = (void __user *)arg;
+	struct fd f;
+	int32_t fd;
+	uint64_t liobn = attr;
+
+	if (get_user(fd, (int32_t __user *)argp))
+		return -EFAULT;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	vfio_group = kvm_vfio_group_get_external_user(f.file);
+	fdput(f);
+
+	list_for_each_entry(kvg, &kv->group_list, node) {
+		if (kvg->vfio_group == vfio_group) {
+			WARN_ON(kvg->liobn);

Users shouldn't be able to trigger WARN_ON so easily, return -EBUSY,
allow it to be unset and re-set, or just allow the overwrite.

quoted

+			kvg->liobn = liobn;
+			kvm_vfio_group_put_external_user(vfio_group);
+			return 0;
+		}
+	}
+
+	kvm_vfio_group_put_external_user(vfio_group);
+
+	return -ENXIO;
+}
+
 static int kvm_vfio_set_attr(struct kvm_device *dev,
 			     struct kvm_device_attr *attr)
 {
 	switch (attr->group) {
 	case KVM_DEV_VFIO_GROUP:
 		return kvm_vfio_set_group(dev, attr->attr, attr->addr);
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return kvm_vfio_set_spapr_tce_liobn(dev, attr->attr,
+				attr->addr);
+#endif
 	}
 
 	return -ENXIO;

@@ -211,6 +252,10 @@ static int kvm_vfio_has_attr(struct kvm_device *dev,
 		}
 
 		break;
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+	case KVM_DEV_VFIO_SPAPR_TCE_LIOBN:
+		return 0;
+#endif
 	}
 
 	return -ENXIO;

@@ -250,6 +295,7 @@ static int kvm_vfio_create(struct kvm_device *dev, u32 type)
 	mutex_init(&kv->lock);
 
 	dev->private = kv;
+	dev->kvm->vfio = kv;
 
 	return 0;
 }

diff --git a/virt/kvm/vfio_rm.c b/virt/kvm/vfio_rm.c
new file mode 100644
index 0000000..ee9fd96
--- /dev/null
+++ b/virt/kvm/vfio_rm.c

@@ -0,0 +1,54 @@
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/kvm_host.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+
+struct kvm_vfio_group {
+	struct list_head node;
+	struct vfio_group *vfio_group;
+	uint64_t liobn; /* sPAPR */
+};
+
+struct kvm_vfio {
+	struct list_head group_list;
+	struct mutex lock;
+	bool noncoherent;
+};
+
+struct vfio_group {
+	struct kref			kref;
+	int				minor;
+	atomic_t			container_users;
+	struct iommu_group		*iommu_group;
+	struct vfio_container		*container;
+	struct list_head		device_list;
+	struct mutex			device_lock;
+	struct device			*dev;
+	struct notifier_block		nb;
+	struct list_head		vfio_next;
+	struct list_head		container_next;
+	atomic_t			opened;
+};
+
+struct iommu_group *vfio_find_group_by_liobn(struct kvm *kvm, unsigned long liobn)
+{
+	struct kvm_vfio_group *kvg;
+
+	if (!kvm->vfio)
+		return NULL;
+
+	list_for_each_entry(kvg, &kvm->vfio->group_list, node) {
+		if (kvg->liobn == liobn)
+			return kvg->vfio_group->iommu_group;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(vfio_find_group_by_liobn);
+
+

You're kidding, right?  These are intentionally private data structures
that are blatantly copied so that you can extract what you want.  NACK.
The iommu_group is available off struct device, do you even need vfio or
this kvm-vfio device to get from liobn to iommu_group?  Thanks,

This is an RFC. I am not saying this is what can go to upstream or
anything. I am not kidding (why everyone assumes that?), I am showing
what API I would like to have in the VFIO KVM device. I need the way to
get iommu_table (which is in a private data of iommu_group) by LIOBN and
the VFIO KVM device is the _only_ entity which will know about this
connection (LIOBN is made up by the qemu and told to the guest) and it
cannot go to the kvm.ko - and the patch like this is the best way to
show it as my english obviously sucks.

Oh. I was confused by:
drivers/vfio/vfio.c|67| struct vfio_group {
drivers/vfio/vfio_iommu_type1.c|73| struct vfio_group {

which are two completely different types (confusing).

So. I either need an additional file to compile to the kernel for mmu-off
case (such as vfio_rm.c) and share vfio_group struct via some internal
header or compile vfio.c into the kernel image always, in this case I'll
need to export kvm_vfio_ops symbol. What would you suggest?



-- 
Alexey