Re: [RFC v2 7/9] KVM: KVM-VFIO: add new VFIO external API hooks

Eric Auger
2014-09-11T08:51:55Z

On 09/11/2014 05:10 AM, Christoffer Dall wrote:
> On Mon, Sep 01, 2014 at 02:52:46PM +0200, Eric Auger wrote:
>> add functions that implement the gateway to the extended
>
> Capital letter when beginning a new sentence. Also the reference to
> 'the extended VFIO API' feels a bit weird. Can't you make your commit
> message a little more descriptive of this patch, something along the
> lines of:
>
> Provide wrapper functions that allows KVM-VFIO device code to get an
> external handle on a struct vfio_device based on a vfio device file
> descriptor. We provide this through three new functions:
>
> (assuming I got this right).
sure
>
>
>
>> external VFIO API:
>> - kvm_vfio_device_get_external_user
>> - kvm_vfio_device_put_external_user
>> - kvm_vfio_external_base_device
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> v1 -> v2:
>> - kvm_vfio_external_get_base_device renamed into
>> kvm_vfio_external_base_device
>> - kvm_vfio_external_get_type removed
>> ---
>> arch/arm/include/asm/kvm_host.h | 5 +++++
>> virt/kvm/vfio.c | 45 +++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 50 insertions(+)
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> index 6dfb404..1aee6bb 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -171,6 +171,11 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
>> unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
>> int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
>>
>> +struct vfio_device;
>> +struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep);
>> +void kvm_vfio_device_put_external_user(struct vfio_device *vdev);
>> +struct device *kvm_vfio_external_base_device(struct vfio_device *vdev);
>> +
>> /* We do not have shadow page tables, hence the empty hooks */
>> static inline int kvm_age_hva(struct kvm *kvm, unsigned long hva)
>> {
>> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
>> index ba1a93f..76dc7a1 100644
>> --- a/virt/kvm/vfio.c
>> +++ b/virt/kvm/vfio.c
>> @@ -59,6 +59,51 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
>> symbol_put(vfio_group_put_external_user);
>> }
>>
>> +struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep)
>> +{
>> + struct vfio_device *vdev;
>> + struct vfio_device *(*fn)(struct file *);
>> +
>> + fn = symbol_get(vfio_device_get_external_user);
>> + if (!fn)
>> + return ERR_PTR(-EINVAL);
>> +
>> + vdev = fn(filep);
>> +
>> + symbol_put(vfio_device_get_external_user);
>> +
>> + return vdev;
>> +}
>> +
>> +void kvm_vfio_device_put_external_user(struct vfio_device *vdev)
>> +{
>> + void (*fn)(struct vfio_device *);
>> +
>> + fn = symbol_get(vfio_device_put_external_user);
>> + if (!fn)
>> + return;
>> +
>> + fn(vdev);
>> +
>> + symbol_put(vfio_device_put_external_user);
>> +}
>> +
>> +struct device *kvm_vfio_external_base_device(struct vfio_device *vdev)
>> +{
>> + struct device *(*fn)(struct vfio_device *);
>> + struct device *dev;
>> +
>> + fn = symbol_get(vfio_external_base_device);
>> + if (!fn)
>> + return NULL;
>> +
>> + dev = fn(vdev);
>> +
>> + symbol_put(vfio_external_base_device);
>> +
>> + return dev;
>> +}
>> +
>> static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
>> {
>> long (*fn)(struct vfio_group *, unsigned long);
>> --
>> 1.9.1
>>
>
> otherwise looks good to me!
> -Christoffer
>