Re: [PATCH] drm/i915/gvt/kvmgt: Fix the build failure in kvmgt.

[Zhenyu Wang <zhenyuw@linux.intel.com>]

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On 2021.02.09 02:52:10 +0800, Yu Zhang wrote:
> Previously, commit 531810caa9f4 ("KVM: x86/mmu: Use
> an rwlock for the x86 MMU") replaced KVM's mmu_lock
> with type rwlock_t. This will cause a build failure
> in kvmgt, which uses the same lock when trying to add/
> remove some GFNs to/from the page tracker. Fix it with
> write_lock/unlocks in kvmgt.

Thanks for the fix! I saw Paolo has already carried one
in -next, so we are fine.

> 
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 60f1a386dd06..b4348256ae95 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1703,7 +1703,7 @@ static int kvmgt_page_track_add(unsigned long handle, u64 gfn)
>  		return -EINVAL;
>  	}
>  
> -	spin_lock(&kvm->mmu_lock);
> +	write_lock(&kvm->mmu_lock);
>  
>  	if (kvmgt_gfn_is_write_protected(info, gfn))
>  		goto out;
> @@ -1712,7 +1712,7 @@ static int kvmgt_page_track_add(unsigned long handle, u64 gfn)
>  	kvmgt_protect_table_add(info, gfn);
>  
>  out:
> -	spin_unlock(&kvm->mmu_lock);
> +	write_unlock(&kvm->mmu_lock);
>  	srcu_read_unlock(&kvm->srcu, idx);
>  	return 0;
>  }
> @@ -1737,7 +1737,7 @@ static int kvmgt_page_track_remove(unsigned long handle, u64 gfn)
>  		return -EINVAL;
>  	}
>  
> -	spin_lock(&kvm->mmu_lock);
> +	write_lock(&kvm->mmu_lock);
>  
>  	if (!kvmgt_gfn_is_write_protected(info, gfn))
>  		goto out;
> @@ -1746,7 +1746,7 @@ static int kvmgt_page_track_remove(unsigned long handle, u64 gfn)
>  	kvmgt_protect_table_del(info, gfn);
>  
>  out:
> -	spin_unlock(&kvm->mmu_lock);
> +	write_unlock(&kvm->mmu_lock);
>  	srcu_read_unlock(&kvm->srcu, idx);
>  	return 0;
>  }
> @@ -1772,7 +1772,7 @@ static void kvmgt_page_track_flush_slot(struct kvm *kvm,
>  	struct kvmgt_guest_info *info = container_of(node,
>  					struct kvmgt_guest_info, track_node);
>  
> -	spin_lock(&kvm->mmu_lock);
> +	write_lock(&kvm->mmu_lock);
>  	for (i = 0; i < slot->npages; i++) {
>  		gfn = slot->base_gfn + i;
>  		if (kvmgt_gfn_is_write_protected(info, gfn)) {
> @@ -1781,7 +1781,7 @@ static void kvmgt_page_track_flush_slot(struct kvm *kvm,
>  			kvmgt_protect_table_del(info, gfn);
>  		}
>  	}
> -	spin_unlock(&kvm->mmu_lock);
> +	write_unlock(&kvm->mmu_lock);
>  }
>  
>  static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu, struct kvm *kvm)
> -- 
> 2.17.1
> 

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