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[PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes

Wei-Lin Chang posted 1 patch 6 months ago 
arch/arm64/kvm/ptdump.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
[PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes
Posted by Wei-Lin Chang 6 months ago 
The attribute masks and test values in the ptdump code are meant for
individual attributes, however for stage-2 ptdump we included PTE_VALID
while testing for R, W, X, and AF. This led to some confusion and the
flipped output for the executable attribute.

Remove PTE_VALID from all attribute masks and values so that each test
matches only the relevant bits.

Additionally, the executable attribute printing is updated to align with
stage-1 ptdump, printing "NX" for non-executable regions and "x " for
executable ones.

Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Sebastian Ene <sebastianene@google.com>
Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw>
---
Tested on QEMU.

Changes in v2, thanks to those listed in the Suggested-by tags:
  - remove PTE_VALID from .mask and .val
  - make executable attribute output format identical to stage-1 ptdump
  - Link to v1: https://lore.kernel.org/kvmarm/20250802104021.3076621-1-r09922117@csie.ntu.edu.tw/
---
 arch/arm64/kvm/ptdump.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index 098416d7e5c25..dc5acfb00af91 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c
@@ -32,23 +32,23 @@ static const struct ptdump_prot_bits stage2_pte_bits[] = {
 		.set	= " ",
 		.clear	= "F",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
 		.set	= "R",
 		.clear	= " ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
 		.set	= "W",
 		.clear	= " ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID,
-		.val	= PTE_VALID,
-		.set	= " ",
-		.clear	= "X",
+		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
+		.val	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
+		.set	= "NX",
+		.clear	= "x ",
 	}, {
-		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
-		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
 		.set	= "AF",
 		.clear	= "  ",
 	}, {
-- 
2.50.1
Re: [PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes
Posted by Marc Zyngier 4 months, 3 weeks ago 
On Sat, 09 Aug 2025 21:53:56 +0800, Wei-Lin Chang wrote:
> The attribute masks and test values in the ptdump code are meant for
> individual attributes, however for stage-2 ptdump we included PTE_VALID
> while testing for R, W, X, and AF. This led to some confusion and the
> flipped output for the executable attribute.
> 
> Remove PTE_VALID from all attribute masks and values so that each test
> matches only the relevant bits.
> 
> [...]

Applied to next, thanks!

[1/1] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes
      commit: 8673e5b22e1e114213d3ca74f415034aed45e528

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.
Re: [PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes
Posted by Will Deacon 5 months ago 
On Sat, Aug 09, 2025 at 09:53:56PM +0800, Wei-Lin Chang wrote:
> The attribute masks and test values in the ptdump code are meant for
> individual attributes, however for stage-2 ptdump we included PTE_VALID
> while testing for R, W, X, and AF. This led to some confusion and the
> flipped output for the executable attribute.
> 
> Remove PTE_VALID from all attribute masks and values so that each test
> matches only the relevant bits.
> 
> Additionally, the executable attribute printing is updated to align with
> stage-1 ptdump, printing "NX" for non-executable regions and "x " for
> executable ones.
> 
> Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Suggested-by: Sebastian Ene <sebastianene@google.com>
> Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw>
> ---
> Tested on QEMU.
> 
> Changes in v2, thanks to those listed in the Suggested-by tags:
>   - remove PTE_VALID from .mask and .val
>   - make executable attribute output format identical to stage-1 ptdump
>   - Link to v1: https://lore.kernel.org/kvmarm/20250802104021.3076621-1-r09922117@csie.ntu.edu.tw/
> ---
>  arch/arm64/kvm/ptdump.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

I assume Oliver or Marc will pick this up via the kvmarm tree.

Cheers,

Will
Re: [PATCH v2] KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes
Posted by Anshuman Khandual 5 months, 4 weeks ago 

On 09/08/25 7:23 PM, Wei-Lin Chang wrote:
> The attribute masks and test values in the ptdump code are meant for
> individual attributes, however for stage-2 ptdump we included PTE_VALID
> while testing for R, W, X, and AF. This led to some confusion and the
> flipped output for the executable attribute.
> 
> Remove PTE_VALID from all attribute masks and values so that each test
> matches only the relevant bits.
> 
> Additionally, the executable attribute printing is updated to align with
> stage-1 ptdump, printing "NX" for non-executable regions and "x " for
> executable ones.
> 
> Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Suggested-by: Sebastian Ene <sebastianene@google.com>
> Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw>
> ---
> Tested on QEMU.
> 
> Changes in v2, thanks to those listed in the Suggested-by tags:
>   - remove PTE_VALID from .mask and .val
>   - make executable attribute output format identical to stage-1 ptdump
>   - Link to v1: https://lore.kernel.org/kvmarm/20250802104021.3076621-1-r09922117@csie.ntu.edu.tw/
> ---
>  arch/arm64/kvm/ptdump.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
> index 098416d7e5c25..dc5acfb00af91 100644
> --- a/arch/arm64/kvm/ptdump.c
> +++ b/arch/arm64/kvm/ptdump.c
> @@ -32,23 +32,23 @@ static const struct ptdump_prot_bits stage2_pte_bits[] = {
>  		.set	= " ",
>  		.clear	= "F",
>  	}, {
> -		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
> -		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
> +		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
> +		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R,
>  		.set	= "R",
>  		.clear	= " ",
>  	}, {
> -		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
> -		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
> +		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
> +		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
>  		.set	= "W",
>  		.clear	= " ",
>  	}, {
> -		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID,
> -		.val	= PTE_VALID,
> -		.set	= " ",
> -		.clear	= "X",
> +		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
> +		.val	= KVM_PTE_LEAF_ATTR_HI_S2_XN,
> +		.set	= "NX",
> +		.clear	= "x ",
>  	}, {
> -		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
> -		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
> +		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
> +		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF,
>  		.set	= "AF",
>  		.clear	= "  ",
>  	}, {

LGTM and consistent with Stage-1.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

Patchew 2.1-devel-b67e4c2

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