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94aa033efc
This fixes a bug introduced with commitc05c4186bb("KVM: s390: add floating irq controller"). get_all_floating_irqs() does copy_to_user() while holding a spin lock. Let's fix this by filling a temporary buffer first and copy it to userspace after giving up the lock. Cc: <stable@vger.kernel.org> # 3.18+:69a8d45626KVM: s390: no need to hold... Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
95 lines
3.4 KiB
Plaintext
95 lines
3.4 KiB
Plaintext
FLIC (floating interrupt controller)
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====================================
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FLIC handles floating (non per-cpu) interrupts, i.e. I/O, service and some
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machine check interruptions. All interrupts are stored in a per-vm list of
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pending interrupts. FLIC performs operations on this list.
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Only one FLIC instance may be instantiated.
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FLIC provides support to
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- add interrupts (KVM_DEV_FLIC_ENQUEUE)
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- inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS)
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- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS)
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- enable/disable for the guest transparent async page faults
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- register and modify adapter interrupt sources (KVM_DEV_FLIC_ADAPTER_*)
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Groups:
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KVM_DEV_FLIC_ENQUEUE
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Passes a buffer and length into the kernel which are then injected into
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the list of pending interrupts.
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attr->addr contains the pointer to the buffer and attr->attr contains
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the length of the buffer.
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The format of the data structure kvm_s390_irq as it is copied from userspace
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is defined in usr/include/linux/kvm.h.
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KVM_DEV_FLIC_GET_ALL_IRQS
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Copies all floating interrupts into a buffer provided by userspace.
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When the buffer is too small it returns -ENOMEM, which is the indication
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for userspace to try again with a bigger buffer.
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-ENOBUFS is returned when the allocation of a kernelspace buffer has
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failed.
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-EFAULT is returned when copying data to userspace failed.
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All interrupts remain pending, i.e. are not deleted from the list of
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currently pending interrupts.
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attr->addr contains the userspace address of the buffer into which all
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interrupt data will be copied.
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attr->attr contains the size of the buffer in bytes.
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KVM_DEV_FLIC_CLEAR_IRQS
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Simply deletes all elements from the list of currently pending floating
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interrupts. No interrupts are injected into the guest.
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KVM_DEV_FLIC_APF_ENABLE
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Enables async page faults for the guest. So in case of a major page fault
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the host is allowed to handle this async and continues the guest.
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KVM_DEV_FLIC_APF_DISABLE_WAIT
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Disables async page faults for the guest and waits until already pending
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async page faults are done. This is necessary to trigger a completion interrupt
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for every init interrupt before migrating the interrupt list.
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KVM_DEV_FLIC_ADAPTER_REGISTER
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Register an I/O adapter interrupt source. Takes a kvm_s390_io_adapter
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describing the adapter to register:
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struct kvm_s390_io_adapter {
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__u32 id;
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__u8 isc;
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__u8 maskable;
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__u8 swap;
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__u8 pad;
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};
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id contains the unique id for the adapter, isc the I/O interruption subclass
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to use, maskable whether this adapter may be masked (interrupts turned off)
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and swap whether the indicators need to be byte swapped.
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KVM_DEV_FLIC_ADAPTER_MODIFY
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Modifies attributes of an existing I/O adapter interrupt source. Takes
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a kvm_s390_io_adapter_req specifiying the adapter and the operation:
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struct kvm_s390_io_adapter_req {
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__u32 id;
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__u8 type;
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__u8 mask;
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__u16 pad0;
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__u64 addr;
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};
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id specifies the adapter and type the operation. The supported operations
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are:
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KVM_S390_IO_ADAPTER_MASK
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mask or unmask the adapter, as specified in mask
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KVM_S390_IO_ADAPTER_MAP
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perform a gmap translation for the guest address provided in addr,
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pin a userspace page for the translated address and add it to the
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list of mappings
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KVM_S390_IO_ADAPTER_UNMAP
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release a userspace page for the translated address specified in addr
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from the list of mappings
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