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* [PATCH] kvm: arm64: Properly align the end address of table walk
@ 2021-01-15  9:53 Keqian Zhu
  2021-01-15 10:23 ` Will Deacon
  0 siblings, 1 reply; 3+ messages in thread
From: Keqian Zhu @ 2021-01-15  9:53 UTC (permalink / raw)
  To: linux-kernel, linux-arm-kernel, kvm, kvmarm, Will Deacon,
	Marc Zyngier, Catalin Marinas
  Cc: Mark Rutland, James Morse, Robin Murphy, Joerg Roedel,
	Daniel Lezcano, Thomas Gleixner, Suzuki K Poulose,
	Julien Thierry, Andrew Morton, Alexios Zavras, wanghaibin.wang,
	jiangkunkun

When align the end address, ought to use its original value.

Fixes: b1e57de62cfb ("KVM: arm64: Add stand-alone page-table walker infrastructure")
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 arch/arm64/kvm/hyp/pgtable.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index bdf8e55ed308..670b0ef12440 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -296,7 +296,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
 	struct kvm_pgtable_walk_data walk_data = {
 		.pgt	= pgt,
 		.addr	= ALIGN_DOWN(addr, PAGE_SIZE),
-		.end	= PAGE_ALIGN(walk_data.addr + size),
+		.end	= PAGE_ALIGN(addr + size),
 		.walker	= walker,
 	};
 
-- 
2.19.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] kvm: arm64: Properly align the end address of table walk
  2021-01-15  9:53 [PATCH] kvm: arm64: Properly align the end address of table walk Keqian Zhu
@ 2021-01-15 10:23 ` Will Deacon
  2021-01-18  1:18   ` Keqian Zhu
  0 siblings, 1 reply; 3+ messages in thread
From: Will Deacon @ 2021-01-15 10:23 UTC (permalink / raw)
  To: Keqian Zhu
  Cc: linux-kernel, linux-arm-kernel, kvm, kvmarm, Marc Zyngier,
	Catalin Marinas, Mark Rutland, James Morse, Robin Murphy,
	Joerg Roedel, Daniel Lezcano, Thomas Gleixner, Suzuki K Poulose,
	Julien Thierry, Andrew Morton, Alexios Zavras, wanghaibin.wang,
	jiangkunkun

On Fri, Jan 15, 2021 at 05:53:07PM +0800, Keqian Zhu wrote:
> When align the end address, ought to use its original value.
> 
> Fixes: b1e57de62cfb ("KVM: arm64: Add stand-alone page-table walker infrastructure")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
>  arch/arm64/kvm/hyp/pgtable.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index bdf8e55ed308..670b0ef12440 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -296,7 +296,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
>  	struct kvm_pgtable_walk_data walk_data = {
>  		.pgt	= pgt,
>  		.addr	= ALIGN_DOWN(addr, PAGE_SIZE),
> -		.end	= PAGE_ALIGN(walk_data.addr + size),
> +		.end	= PAGE_ALIGN(addr + size),
>  		.walker	= walker,

Hmm, this is a change in behaviour, no (consider the case where both 'addr'
and 'size' are misaligned)? The current code is consistent with the
kerneldoc in asm/kvm_pgtable.h, so I don't see the motivation to change it.

Did you hit a bug somewhere?

Will

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] kvm: arm64: Properly align the end address of table walk
  2021-01-15 10:23 ` Will Deacon
@ 2021-01-18  1:18   ` Keqian Zhu
  0 siblings, 0 replies; 3+ messages in thread
From: Keqian Zhu @ 2021-01-18  1:18 UTC (permalink / raw)
  To: Will Deacon
  Cc: linux-kernel, linux-arm-kernel, kvm, kvmarm, Marc Zyngier,
	Catalin Marinas, Mark Rutland, James Morse, Robin Murphy,
	Joerg Roedel, Daniel Lezcano, Thomas Gleixner, Suzuki K Poulose,
	Julien Thierry, Andrew Morton, Alexios Zavras, wanghaibin.wang,
	jiangkunkun



On 2021/1/15 18:23, Will Deacon wrote:
> On Fri, Jan 15, 2021 at 05:53:07PM +0800, Keqian Zhu wrote:
>> When align the end address, ought to use its original value.
>>
>> Fixes: b1e57de62cfb ("KVM: arm64: Add stand-alone page-table walker infrastructure")
>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>> ---
>>  arch/arm64/kvm/hyp/pgtable.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
>> index bdf8e55ed308..670b0ef12440 100644
>> --- a/arch/arm64/kvm/hyp/pgtable.c
>> +++ b/arch/arm64/kvm/hyp/pgtable.c
>> @@ -296,7 +296,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
>>  	struct kvm_pgtable_walk_data walk_data = {
>>  		.pgt	= pgt,
>>  		.addr	= ALIGN_DOWN(addr, PAGE_SIZE),
>> -		.end	= PAGE_ALIGN(walk_data.addr + size),
>> +		.end	= PAGE_ALIGN(addr + size),
>>  		.walker	= walker,
> 
> Hmm, this is a change in behaviour, no (consider the case where both 'addr'
> and 'size' are misaligned)? The current code is consistent with the
> kerneldoc in asm/kvm_pgtable.h, so I don't see the motivation to change it.
> 
> Did you hit a bug somewhere?
> 
> Will
> .
>
Not hit a bug, I just read the code to implement a new idea of stage2 DBM
support [1]. Yes, according to doc, this is not an issue ("The offset of
@addr within a page is ignored."). Sorry to disturb ;-).

[1] https://lore.kernel.org/kvmarm/fd26654b-8258-061c-2a69-90b961c1c71b@huawei.com/

Thanks,
Keqian






^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-01-18  1:20 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-01-15  9:53 [PATCH] kvm: arm64: Properly align the end address of table walk Keqian Zhu
2021-01-15 10:23 ` Will Deacon
2021-01-18  1:18   ` Keqian Zhu

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