diff mbox

[2/3] kvm: arm/arm64: Take mmap_sem in kvm_arch_prepare_memory_region

Message ID 1489503154-20705-3-git-send-email-suzuki.poulose@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Suzuki K Poulose March 14, 2017, 2:52 p.m. UTC 
From: Marc Zyngier <marc.zyngier@arm.com>

We don't hold the mmap_sem while searching for VMAs (via find_vma), in
kvm_arch_prepare_memory_region, which can end up in expected failures.

Fixes: commit 8eef91239e57 ("arm/arm64: KVM: map MMIO regions at creation time")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Eric Auger <eric.auger@rehat.com>
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[ Handle dirty page logging failure case ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm/kvm/mmu.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Christoffer Dall March 15, 2017, 11:05 a.m. UTC | #1 
On Tue, Mar 14, 2017 at 02:52:33PM +0000, Suzuki K Poulose wrote:
> From: Marc Zyngier <marc.zyngier@arm.com>
> 
> We don't hold the mmap_sem while searching for VMAs (via find_vma), in
> kvm_arch_prepare_memory_region, which can end up in expected failures.
> 
> Fixes: commit 8eef91239e57 ("arm/arm64: KVM: map MMIO regions at creation time")
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Christoffer Dall <christoffer.dall@linaro.org>
> Cc: Eric Auger <eric.auger@rehat.com>
> Cc: stable@vger.kernel.org # v3.18+
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> [ Handle dirty page logging failure case ]
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Reviewed-by: Christoffer Dall <cdall@linaro.org>

> ---
>  arch/arm/kvm/mmu.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index f2e2e0c..13b9c1f 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -1803,6 +1803,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
>  	    (KVM_PHYS_SIZE >> PAGE_SHIFT))
>  		return -EFAULT;
>  
> +	down_read(&current->mm->mmap_sem);
>  	/*
>  	 * A memory region could potentially cover multiple VMAs, and any holes
>  	 * between them, so iterate over all of them to find out if we can map
> @@ -1846,8 +1847,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
>  			pa += vm_start - vma->vm_start;
>  
>  			/* IO region dirty page logging not allowed */
> -			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES)
> -				return -EINVAL;
> +			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
> +				ret = -EINVAL;
> +				goto out;
> +			}
>  
>  			ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
>  						    vm_end - vm_start,
> @@ -1859,7 +1862,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
>  	} while (hva < reg_end);
>  
>  	if (change == KVM_MR_FLAGS_ONLY)
> -		return ret;
> +		goto out;
>  
>  	spin_lock(&kvm->mmu_lock);
>  	if (ret)
> @@ -1867,6 +1870,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
>  	else
>  		stage2_flush_memslot(kvm, memslot);
>  	spin_unlock(&kvm->mmu_lock);
> +out:
> +	up_read(&current->mm->mmap_sem);
>  	return ret;
>  }
>  
> -- 
> 2.7.4
>
diff mbox

Patch

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index f2e2e0c..13b9c1f 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1803,6 +1803,7 @@  int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	    (KVM_PHYS_SIZE >> PAGE_SHIFT))
 		return -EFAULT;
 
+	down_read(&current->mm->mmap_sem);
 	/*
 	 * A memory region could potentially cover multiple VMAs, and any holes
 	 * between them, so iterate over all of them to find out if we can map
@@ -1846,8 +1847,10 @@  int kvm_arch_prepare_memory_region(struct kvm *kvm,
 			pa += vm_start - vma->vm_start;
 
 			/* IO region dirty page logging not allowed */
-			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES)
-				return -EINVAL;
+			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+				ret = -EINVAL;
+				goto out;
+			}
 
 			ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
 						    vm_end - vm_start,
@@ -1859,7 +1862,7 @@  int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	} while (hva < reg_end);
 
 	if (change == KVM_MR_FLAGS_ONLY)
-		return ret;
+		goto out;
 
 	spin_lock(&kvm->mmu_lock);
 	if (ret)
@@ -1867,6 +1870,8 @@  int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	else
 		stage2_flush_memslot(kvm, memslot);
 	spin_unlock(&kvm->mmu_lock);
+out:
+	up_read(&current->mm->mmap_sem);
 	return ret;
 }