[v3,27/32] KVM: arm64: Refactor stage2_map_set_prot_attr()
diff mbox series

Message ID 20210302150002.3685113-28-qperret@google.com
State New, archived
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Series
  • KVM: arm64: A stage 2 for the host
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Commit Message

Quentin Perret March 2, 2021, 2:59 p.m. UTC
In order to ease its re-use in other code paths, refactor
stage2_map_set_prot_attr() to not depend on a stage2_map_data struct.
No functional change intended.

Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/pgtable.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

Comments

Will Deacon March 4, 2021, 8:03 p.m. UTC | #1
On Tue, Mar 02, 2021 at 02:59:57PM +0000, Quentin Perret wrote:
> In order to ease its re-use in other code paths, refactor
> stage2_map_set_prot_attr() to not depend on a stage2_map_data struct.
> No functional change intended.
> 
> Signed-off-by: Quentin Perret <qperret@google.com>
> ---
>  arch/arm64/kvm/hyp/pgtable.c | 19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index 8e7059fcfd40..8aa01a9e2603 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -494,8 +494,7 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
>  	return vtcr;
>  }
>  
> -static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
> -				    struct stage2_map_data *data)
> +static kvm_pte_t stage2_get_prot_attr(enum kvm_pgtable_prot prot)
>  {
>  	bool device = prot & KVM_PGTABLE_PROT_DEVICE;
>  	kvm_pte_t attr = device ? PAGE_S2_MEMATTR(DEVICE_nGnRE) :
> @@ -504,15 +503,15 @@ static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
>  
>  	if (prot & KVM_PGTABLE_PROT_NONE) {
>  		if (prot != KVM_PGTABLE_PROT_NONE)
> -			return -EINVAL;
> +			return 0;

Hmm, does the architecture actually say that having all these attributes
as 0 is illegal? If not, I think it would be better to keep the int return
code and replace the 'data' parameter with a pointer to a kvm_pte_t.

Does that work?

Will
Quentin Perret March 5, 2021, 9:18 a.m. UTC | #2
On Thursday 04 Mar 2021 at 20:03:36 (+0000), Will Deacon wrote:
> On Tue, Mar 02, 2021 at 02:59:57PM +0000, Quentin Perret wrote:
> > In order to ease its re-use in other code paths, refactor
> > stage2_map_set_prot_attr() to not depend on a stage2_map_data struct.
> > No functional change intended.
> > 
> > Signed-off-by: Quentin Perret <qperret@google.com>
> > ---
> >  arch/arm64/kvm/hyp/pgtable.c | 19 ++++++++-----------
> >  1 file changed, 8 insertions(+), 11 deletions(-)
> > 
> > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > index 8e7059fcfd40..8aa01a9e2603 100644
> > --- a/arch/arm64/kvm/hyp/pgtable.c
> > +++ b/arch/arm64/kvm/hyp/pgtable.c
> > @@ -494,8 +494,7 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
> >  	return vtcr;
> >  }
> >  
> > -static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
> > -				    struct stage2_map_data *data)
> > +static kvm_pte_t stage2_get_prot_attr(enum kvm_pgtable_prot prot)
> >  {
> >  	bool device = prot & KVM_PGTABLE_PROT_DEVICE;
> >  	kvm_pte_t attr = device ? PAGE_S2_MEMATTR(DEVICE_nGnRE) :
> > @@ -504,15 +503,15 @@ static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
> >  
> >  	if (prot & KVM_PGTABLE_PROT_NONE) {
> >  		if (prot != KVM_PGTABLE_PROT_NONE)
> > -			return -EINVAL;
> > +			return 0;
> 
> Hmm, does the architecture actually say that having all these attributes
> as 0 is illegal?

Hmm, that's a good point, that might not be the case. I assumed we would
have no use for this, but there we can easily avoid the restriction
so...

> If not, I think it would be better to keep the int return
> code and replace the 'data' parameter with a pointer to a kvm_pte_t.
> 
> Does that work?

I think so yes, I'll fix it up.

Cheers,
Quentin

Patch
diff mbox series

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 8e7059fcfd40..8aa01a9e2603 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -494,8 +494,7 @@  u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
 	return vtcr;
 }
 
-static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
-				    struct stage2_map_data *data)
+static kvm_pte_t stage2_get_prot_attr(enum kvm_pgtable_prot prot)
 {
 	bool device = prot & KVM_PGTABLE_PROT_DEVICE;
 	kvm_pte_t attr = device ? PAGE_S2_MEMATTR(DEVICE_nGnRE) :
@@ -504,15 +503,15 @@  static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
 
 	if (prot & KVM_PGTABLE_PROT_NONE) {
 		if (prot != KVM_PGTABLE_PROT_NONE)
-			return -EINVAL;
+			return 0;
 		attr |= KVM_PTE_LEAF_SW_BIT_PROT_NONE;
-		goto out;
+		return attr;
 	}
 
 	if (!(prot & KVM_PGTABLE_PROT_X))
 		attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
 	else if (device)
-		return -EINVAL;
+		return 0;
 
 	if (prot & KVM_PGTABLE_PROT_R)
 		attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
@@ -523,9 +522,7 @@  static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
 	attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
 	attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
 
-out:
-	data->attr = attr;
-	return 0;
+	return attr;
 }
 
 static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
@@ -708,9 +705,9 @@  int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 		.arg		= &map_data,
 	};
 
-	ret = stage2_map_set_prot_attr(prot, &map_data);
-	if (ret)
-		return ret;
+	map_data.attr = stage2_get_prot_attr(prot);
+	if (!map_data.attr)
+		return -EINVAL;
 
 	ret = kvm_pgtable_walk(pgt, addr, size, &walker);
 	dsb(ishst);