[PATCH] KVM: arm64: Fix detection of shared VMAs on guest fault

[PATCH] KVM: arm64: Fix detection of shared VMAs on guest fault

[Marc Zyngier]

When merging the KVM MTE support, the blob that was interposed between
the chair and the keyboard experienced a neuronal accident (also known
as a brain fart), turning a check for VM_SHARED into VM_PFNMAP as it
was reshuffling some of the code.

The blob having now come back to its senses, let's restore the
initial check that the original author got right the first place.

Fixes: ea7fc1bb1cd1 ("KVM: arm64: Introduce MTE VM feature")
Cc: Steven Price <steven.price@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 3155c9e778f0..0625bf2353c2 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -947,7 +947,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		vma_shift = get_vma_page_shift(vma, hva);
 	}
 
-	shared = (vma->vm_flags & VM_PFNMAP);
+	shared = (vma->vm_flags & VM_SHARED);
 
 	switch (vma_shift) {
 #ifndef __PAGETABLE_PMD_FOLDED
-- 
2.30.2


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Re: [PATCH] KVM: arm64: Fix detection of shared VMAs on guest fault

[Steven Price]

On 13/07/2021 12:48, Marc Zyngier wrote:
> When merging the KVM MTE support, the blob that was interposed between
> the chair and the keyboard experienced a neuronal accident (also known
> as a brain fart), turning a check for VM_SHARED into VM_PFNMAP as it
> was reshuffling some of the code.
> 
> The blob having now come back to its senses, let's restore the
> initial check that the original author got right the first place.
> 
> Fixes: ea7fc1bb1cd1 ("KVM: arm64: Introduce MTE VM feature")
> Cc: Steven Price <steven.price@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Steven Price <steven.price@arm.com>

Somehow this blob missed it too while reviewing the changes you'd made.

Thanks,

Steve

> ---
>  arch/arm64/kvm/mmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 3155c9e778f0..0625bf2353c2 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -947,7 +947,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  		vma_shift = get_vma_page_shift(vma, hva);
>  	}
>  
> -	shared = (vma->vm_flags & VM_PFNMAP);
> +	shared = (vma->vm_flags & VM_SHARED);
>  
>  	switch (vma_shift) {
>  #ifndef __PAGETABLE_PMD_FOLDED
> 


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