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* [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
@ 2021-05-23 15:53 ` Nicholas Piggin
  0 siblings, 0 replies; 6+ messages in thread
From: Nicholas Piggin @ 2021-05-23 15:53 UTC (permalink / raw)
  To: kvm-ppc; +Cc: linuxppc-dev, Nicholas Piggin

real_vmalloc_addr() does not currently work for huge vmalloc, which is
what the reverse map can be allocated with for radix host, hash guest.

Add huge page awareness to the function.

Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 7af7c70f1468..5f68cb5cc009 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -26,16 +26,23 @@
 static void *real_vmalloc_addr(void *x)
 {
 	unsigned long addr = (unsigned long) x;
+	unsigned long mask;
+	int shift;
 	pte_t *p;
+
 	/*
-	 * assume we don't have huge pages in vmalloc space...
-	 * So don't worry about THP collapse/split. Called
-	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
+	 * This is called only in realmode with MSR_EE = 0, hence won't need
+	 * irq_save/restore around find_init_mm_pte.
 	 */
-	p = find_init_mm_pte(addr, NULL);
+	p = find_init_mm_pte(addr, &shift);
 	if (!p || !pte_present(*p))
 		return NULL;
-	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
+	if (!shift)
+		shift = PAGE_SHIFT;
+
+	mask = (1UL << shift) - 1;
+	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);
+
 	return __va(addr);
 }
 
-- 
2.23.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
@ 2021-05-23 15:53 ` Nicholas Piggin
  0 siblings, 0 replies; 6+ messages in thread
From: Nicholas Piggin @ 2021-05-23 15:53 UTC (permalink / raw)
  To: kvm-ppc; +Cc: linuxppc-dev, Nicholas Piggin

real_vmalloc_addr() does not currently work for huge vmalloc, which is
what the reverse map can be allocated with for radix host, hash guest.

Add huge page awareness to the function.

Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 7af7c70f1468..5f68cb5cc009 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -26,16 +26,23 @@
 static void *real_vmalloc_addr(void *x)
 {
 	unsigned long addr = (unsigned long) x;
+	unsigned long mask;
+	int shift;
 	pte_t *p;
+
 	/*
-	 * assume we don't have huge pages in vmalloc space...
-	 * So don't worry about THP collapse/split. Called
-	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
+	 * This is called only in realmode with MSR_EE = 0, hence won't need
+	 * irq_save/restore around find_init_mm_pte.
 	 */
-	p = find_init_mm_pte(addr, NULL);
+	p = find_init_mm_pte(addr, &shift);
 	if (!p || !pte_present(*p))
 		return NULL;
-	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
+	if (!shift)
+		shift = PAGE_SHIFT;
+
+	mask = (1UL << shift) - 1;
+	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);
+
 	return __va(addr);
 }
 
-- 
2.23.0

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
  2021-05-23 15:53 ` Nicholas Piggin
@ 2021-05-23 16:10   ` Christophe Leroy
  -1 siblings, 0 replies; 6+ messages in thread
From: Christophe Leroy @ 2021-05-23 16:10 UTC (permalink / raw)
  To: Nicholas Piggin; +Cc: linuxppc-dev, kvm-ppc

Nicholas Piggin <npiggin@gmail.com> a écrit :

> real_vmalloc_addr() does not currently work for huge vmalloc, which is
> what the reverse map can be allocated with for radix host, hash guest.
>
> Add huge page awareness to the function.
>
> Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c  
> b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 7af7c70f1468..5f68cb5cc009 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -26,16 +26,23 @@
>  static void *real_vmalloc_addr(void *x)
>  {
>  	unsigned long addr = (unsigned long) x;
> +	unsigned long mask;
> +	int shift;
>  	pte_t *p;
> +
>  	/*
> -	 * assume we don't have huge pages in vmalloc space...
> -	 * So don't worry about THP collapse/split. Called
> -	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
> +	 * This is called only in realmode with MSR_EE = 0, hence won't need
> +	 * irq_save/restore around find_init_mm_pte.
>  	 */
> -	p = find_init_mm_pte(addr, NULL);
> +	p = find_init_mm_pte(addr, &shift);
>  	if (!p || !pte_present(*p))
>  		return NULL;
> -	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
> +	if (!shift)
> +		shift = PAGE_SHIFT;
> +
> +	mask = (1UL << shift) - 1;
> +	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);

Looks strange, before we have ~MASK now we have mask without the ~

Also use PFN_PHYS() instead of open coding ?




> +
>  	return __va(addr);
>  }
>
> --
> 2.23.0



^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
@ 2021-05-23 16:10   ` Christophe Leroy
  0 siblings, 0 replies; 6+ messages in thread
From: Christophe Leroy @ 2021-05-23 16:10 UTC (permalink / raw)
  To: Nicholas Piggin; +Cc: linuxppc-dev, kvm-ppc

Nicholas Piggin <npiggin@gmail.com> a écrit :

> real_vmalloc_addr() does not currently work for huge vmalloc, which is
> what the reverse map can be allocated with for radix host, hash guest.
>
> Add huge page awareness to the function.
>
> Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c  
> b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 7af7c70f1468..5f68cb5cc009 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -26,16 +26,23 @@
>  static void *real_vmalloc_addr(void *x)
>  {
>  	unsigned long addr = (unsigned long) x;
> +	unsigned long mask;
> +	int shift;
>  	pte_t *p;
> +
>  	/*
> -	 * assume we don't have huge pages in vmalloc space...
> -	 * So don't worry about THP collapse/split. Called
> -	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
> +	 * This is called only in realmode with MSR_EE = 0, hence won't need
> +	 * irq_save/restore around find_init_mm_pte.
>  	 */
> -	p = find_init_mm_pte(addr, NULL);
> +	p = find_init_mm_pte(addr, &shift);
>  	if (!p || !pte_present(*p))
>  		return NULL;
> -	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
> +	if (!shift)
> +		shift = PAGE_SHIFT;
> +
> +	mask = (1UL << shift) - 1;
> +	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);

Looks strange, before we have ~MASK now we have mask without the ~

Also use PFN_PHYS() instead of open coding ?




> +
>  	return __va(addr);
>  }
>
> --
> 2.23.0


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
  2021-05-23 16:10   ` Christophe Leroy
@ 2021-05-24  7:59     ` Aneesh Kumar K.V
  -1 siblings, 0 replies; 6+ messages in thread
From: Aneesh Kumar K.V @ 2021-05-24  7:47 UTC (permalink / raw)
  To: Christophe Leroy, Nicholas Piggin; +Cc: linuxppc-dev, kvm-ppc

Christophe Leroy <christophe.leroy@csgroup.eu> writes:

> Nicholas Piggin <npiggin@gmail.com> a écrit :
>
>> real_vmalloc_addr() does not currently work for huge vmalloc, which is
>> what the reverse map can be allocated with for radix host, hash guest.
>>
>> Add huge page awareness to the function.
>>
>> Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>> ---
>>  arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
>>  1 file changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c  
>> b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> index 7af7c70f1468..5f68cb5cc009 100644
>> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> @@ -26,16 +26,23 @@
>>  static void *real_vmalloc_addr(void *x)
>>  {
>>  	unsigned long addr = (unsigned long) x;
>> +	unsigned long mask;
>> +	int shift;
>>  	pte_t *p;
>> +
>>  	/*
>> -	 * assume we don't have huge pages in vmalloc space...
>> -	 * So don't worry about THP collapse/split. Called
>> -	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
>> +	 * This is called only in realmode with MSR_EE = 0, hence won't need
>> +	 * irq_save/restore around find_init_mm_pte.
>>  	 */
>> -	p = find_init_mm_pte(addr, NULL);
>> +	p = find_init_mm_pte(addr, &shift);
>>  	if (!p || !pte_present(*p))
>>  		return NULL;
>> -	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
>> +	if (!shift)
>> +		shift = PAGE_SHIFT;
>> +
>> +	mask = (1UL << shift) - 1;
>> +	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);
>
> Looks strange, before we have ~MASK now we have mask without the ~

#define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))

-aneesh

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc
@ 2021-05-24  7:59     ` Aneesh Kumar K.V
  0 siblings, 0 replies; 6+ messages in thread
From: Aneesh Kumar K.V @ 2021-05-24  7:59 UTC (permalink / raw)
  To: Christophe Leroy, Nicholas Piggin; +Cc: linuxppc-dev, kvm-ppc

Christophe Leroy <christophe.leroy@csgroup.eu> writes:

> Nicholas Piggin <npiggin@gmail.com> a écrit :
>
>> real_vmalloc_addr() does not currently work for huge vmalloc, which is
>> what the reverse map can be allocated with for radix host, hash guest.
>>
>> Add huge page awareness to the function.
>>
>> Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>> ---
>>  arch/powerpc/kvm/book3s_hv_rm_mmu.c | 17 ++++++++++++-----
>>  1 file changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c  
>> b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> index 7af7c70f1468..5f68cb5cc009 100644
>> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
>> @@ -26,16 +26,23 @@
>>  static void *real_vmalloc_addr(void *x)
>>  {
>>  	unsigned long addr = (unsigned long) x;
>> +	unsigned long mask;
>> +	int shift;
>>  	pte_t *p;
>> +
>>  	/*
>> -	 * assume we don't have huge pages in vmalloc space...
>> -	 * So don't worry about THP collapse/split. Called
>> -	 * Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
>> +	 * This is called only in realmode with MSR_EE = 0, hence won't need
>> +	 * irq_save/restore around find_init_mm_pte.
>>  	 */
>> -	p = find_init_mm_pte(addr, NULL);
>> +	p = find_init_mm_pte(addr, &shift);
>>  	if (!p || !pte_present(*p))
>>  		return NULL;
>> -	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
>> +	if (!shift)
>> +		shift = PAGE_SHIFT;
>> +
>> +	mask = (1UL << shift) - 1;
>> +	addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & mask);
>
> Looks strange, before we have ~MASK now we have mask without the ~

#define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))

-aneesh

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-05-24  7:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-23 15:53 [PATCH] KVM: PPC: Book3S HV: Fix reverse map real-mode address lookup with huge vmalloc Nicholas Piggin
2021-05-23 15:53 ` Nicholas Piggin
2021-05-23 16:10 ` Christophe Leroy
2021-05-23 16:10   ` Christophe Leroy
2021-05-24  7:47   ` Aneesh Kumar K.V
2021-05-24  7:59     ` Aneesh Kumar K.V

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