Re: [PATCH 12/15] arm: kvm: Move fake PGD handling to arch specific files

[Christoffer Dall]

On Wed, Oct 07, 2015 at 11:23:52AM +0100, Marc Zyngier wrote:
> On 15/09/15 16:41, Suzuki K. Poulose wrote:
> > From: "Suzuki K. Poulose" 
> > 
> > Rearrange the code for fake pgd handling, which is applicable
> > to only ARM64. The intention is to keep the common code cleaner,
> > unaware of the underlying hacks.
> > 
> > Cc: kvm...@lists.cs.columbia.edu
> > Cc: christoffer.d...@linaro.org
> > Cc: marc.zyng...@arm.com
> > Signed-off-by: Suzuki K. Poulose 
> > ---
> >  arch/arm/include/asm/kvm_mmu.h   |7 ++
> >  arch/arm/kvm/mmu.c   |   44 
> > +-
> >  arch/arm64/include/asm/kvm_mmu.h |   43 
> > +
> >  3 files changed, 55 insertions(+), 39 deletions(-)
> > 
> > diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> > index 405aa18..1c9aa8a 100644
> > --- a/arch/arm/include/asm/kvm_mmu.h
> > +++ b/arch/arm/include/asm/kvm_mmu.h
> > @@ -173,6 +173,13 @@ static inline unsigned int kvm_get_hwpgd_size(void)
> > return PTRS_PER_S2_PGD * sizeof(pgd_t);
> >  }
> >  
> > +static inline pgd_t *kvm_setup_fake_pgd(pgd_t *pgd)
> > +{
> > +   return pgd;
> > +}
> > +
> > +static inline void kvm_free_fake_pgd(pgd_t *pgd) {}
> > +
> >  struct kvm;
> >  
> >  #define kvm_flush_dcache_to_poc(a,l)   __cpuc_flush_dcache_area((a), 
> > (l))
> > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> > index 7b42012..b210622 100644
> > --- a/arch/arm/kvm/mmu.c
> > +++ b/arch/arm/kvm/mmu.c
> > @@ -677,43 +677,11 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm)
> >  * guest, we allocate a fake PGD and pre-populate it to point
> >  * to the next-level page table, which will be the real
> >  * initial page table pointed to by the VTTBR.
> > -*
> > -* When KVM_PREALLOC_LEVEL==2, we allocate a single page for
> > -* the PMD and the kernel will use folded pud.
> > -* When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
> > -* pages.
> >  */
> > -   if (KVM_PREALLOC_LEVEL > 0) {
> > -   int i;
> > -
> > -   /*
> > -* Allocate fake pgd for the page table manipulation macros to
> > -* work.  This is not used by the hardware and we have no
> > -* alignment requirement for this allocation.
> > -*/
> > -   pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
> > -   GFP_KERNEL | __GFP_ZERO);
> > -
> > -   if (!pgd) {
> > -   kvm_free_hwpgd(hwpgd);
> > -   return -ENOMEM;
> > -   }
> > -
> > -   /* Plug the HW PGD into the fake one. */
> > -   for (i = 0; i < PTRS_PER_S2_PGD; i++) {
> > -   if (KVM_PREALLOC_LEVEL == 1)
> > -   pgd_populate(NULL, pgd + i,
> > -(pud_t *)hwpgd + i * PTRS_PER_PUD);
> > -   else if (KVM_PREALLOC_LEVEL == 2)
> > -   pud_populate(NULL, pud_offset(pgd, 0) + i,
> > -(pmd_t *)hwpgd + i * PTRS_PER_PMD);
> > -   }
> > -   } else {
> > -   /*
> > -* Allocate actual first-level Stage-2 page table used by the
> > -* hardware for Stage-2 page table walks.
> > -*/
> > -   pgd = (pgd_t *)hwpgd;
> > +   pgd = kvm_setup_fake_pgd(hwpgd);
> > +   if (IS_ERR(pgd)) {
> > +   kvm_free_hwpgd(hwpgd);
> > +   return PTR_ERR(pgd);
> > }
> >  
> > kvm_clean_pgd(pgd);
> > @@ -820,9 +788,7 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
> >  
> > unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
> > kvm_free_hwpgd(kvm_get_hwpgd(kvm));
> > -   if (KVM_PREALLOC_LEVEL > 0)
> > -   kfree(kvm->arch.pgd);
> > -
> > +   kvm_free_fake_pgd(kvm->arch.pgd);
> > kvm->arch.pgd = NULL;
> >  }
> >  
> > diff --git a/arch/arm64/include/asm/kvm_mmu.h 
> > b/arch/arm64/include/asm/kvm_mmu.h
> > index 6150567..2567fe8 100644
> > --- a/arch/arm64/include/asm/kvm_mmu.h
> > +++ b/arch/arm64/include/asm/kvm_mmu.h
> > @@ -198,6 +198,49 @@ static inline unsigned int kvm_get_hwpgd_size(void)
> > return PTRS_PER_S2_PGD * sizeof(pgd_t);
> >  }
> >  
> > +/*
> > + * Allocate fake pgd for the page table manipulation macros to
> > + * work.  This is not used by the hardware and we have no
> > + * alignment requirement for this allocation.
> > + */
> > +static inline pgd_t* kvm_setup_fake_pgd(pgd_t *hwpgd)
> > +{
> > +   int i;
> > +   pgd_t *pgd;
> > +
> > +   if (!KVM_PREALLOC_LEVEL)
> > +   return hwpgd;
> > +   /*
> > +* When KVM_PREALLOC_LEVEL==2, we allocate a single page for
> > +* the PMD and the kernel will use folded pud.
> > +* When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
> > +* pages.
> > +*/
> > +   pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
> > +   GFP_KERNEL | __GFP_ZERO);
> > +
> > +   

Re: [PATCH 12/15] arm: kvm: Move fake PGD handling to arch specific files

[Marc Zyngier]

On 15/09/15 16:41, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" 
> 
> Rearrange the code for fake pgd handling, which is applicable
> to only ARM64. The intention is to keep the common code cleaner,
> unaware of the underlying hacks.
> 
> Cc: kvm...@lists.cs.columbia.edu
> Cc: christoffer.d...@linaro.org
> Cc: marc.zyng...@arm.com
> Signed-off-by: Suzuki K. Poulose 
> ---
>  arch/arm/include/asm/kvm_mmu.h   |7 ++
>  arch/arm/kvm/mmu.c   |   44 
> +-
>  arch/arm64/include/asm/kvm_mmu.h |   43 +
>  3 files changed, 55 insertions(+), 39 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 405aa18..1c9aa8a 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -173,6 +173,13 @@ static inline unsigned int kvm_get_hwpgd_size(void)
>   return PTRS_PER_S2_PGD * sizeof(pgd_t);
>  }
>  
> +static inline pgd_t *kvm_setup_fake_pgd(pgd_t *pgd)
> +{
> + return pgd;
> +}
> +
> +static inline void kvm_free_fake_pgd(pgd_t *pgd) {}
> +
>  struct kvm;
>  
>  #define kvm_flush_dcache_to_poc(a,l) __cpuc_flush_dcache_area((a), (l))
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 7b42012..b210622 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -677,43 +677,11 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm)
>* guest, we allocate a fake PGD and pre-populate it to point
>* to the next-level page table, which will be the real
>* initial page table pointed to by the VTTBR.
> -  *
> -  * When KVM_PREALLOC_LEVEL==2, we allocate a single page for
> -  * the PMD and the kernel will use folded pud.
> -  * When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
> -  * pages.
>*/
> - if (KVM_PREALLOC_LEVEL > 0) {
> - int i;
> -
> - /*
> -  * Allocate fake pgd for the page table manipulation macros to
> -  * work.  This is not used by the hardware and we have no
> -  * alignment requirement for this allocation.
> -  */
> - pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
> - GFP_KERNEL | __GFP_ZERO);
> -
> - if (!pgd) {
> - kvm_free_hwpgd(hwpgd);
> - return -ENOMEM;
> - }
> -
> - /* Plug the HW PGD into the fake one. */
> - for (i = 0; i < PTRS_PER_S2_PGD; i++) {
> - if (KVM_PREALLOC_LEVEL == 1)
> - pgd_populate(NULL, pgd + i,
> -  (pud_t *)hwpgd + i * PTRS_PER_PUD);
> - else if (KVM_PREALLOC_LEVEL == 2)
> - pud_populate(NULL, pud_offset(pgd, 0) + i,
> -  (pmd_t *)hwpgd + i * PTRS_PER_PMD);
> - }
> - } else {
> - /*
> -  * Allocate actual first-level Stage-2 page table used by the
> -  * hardware for Stage-2 page table walks.
> -  */
> - pgd = (pgd_t *)hwpgd;
> + pgd = kvm_setup_fake_pgd(hwpgd);
> + if (IS_ERR(pgd)) {
> + kvm_free_hwpgd(hwpgd);
> + return PTR_ERR(pgd);
>   }
>  
>   kvm_clean_pgd(pgd);
> @@ -820,9 +788,7 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
>  
>   unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
>   kvm_free_hwpgd(kvm_get_hwpgd(kvm));
> - if (KVM_PREALLOC_LEVEL > 0)
> - kfree(kvm->arch.pgd);
> -
> + kvm_free_fake_pgd(kvm->arch.pgd);
>   kvm->arch.pgd = NULL;
>  }
>  
> diff --git a/arch/arm64/include/asm/kvm_mmu.h 
> b/arch/arm64/include/asm/kvm_mmu.h
> index 6150567..2567fe8 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -198,6 +198,49 @@ static inline unsigned int kvm_get_hwpgd_size(void)
>   return PTRS_PER_S2_PGD * sizeof(pgd_t);
>  }
>  
> +/*
> + * Allocate fake pgd for the page table manipulation macros to
> + * work.  This is not used by the hardware and we have no
> + * alignment requirement for this allocation.
> + */
> +static inline pgd_t* kvm_setup_fake_pgd(pgd_t *hwpgd)
> +{
> + int i;
> + pgd_t *pgd;
> +
> + if (!KVM_PREALLOC_LEVEL)
> + return hwpgd;
> + /*
> +  * When KVM_PREALLOC_LEVEL==2, we allocate a single page for
> +  * the PMD and the kernel will use folded pud.
> +  * When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
> +  * pages.
> +  */
> + pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
> + GFP_KERNEL | __GFP_ZERO);
> +
> + if (!pgd)
> + return ERR_PTR(-ENOMEM);
> +
> + /* Plug the HW PGD into the fake one. */
> + for (i = 0; i < PTRS_PER_S2_PGD; i++) {
> + if (KVM_PREALLOC_LEVEL == 1)
> +

[PATCH 12/15] arm: kvm: Move fake PGD handling to arch specific files

[Suzuki K. Poulose]

From: "Suzuki K. Poulose" 

Rearrange the code for fake pgd handling, which is applicable
to only ARM64. The intention is to keep the common code cleaner,
unaware of the underlying hacks.

Cc: kvm...@lists.cs.columbia.edu
Cc: christoffer.d...@linaro.org
Cc: marc.zyng...@arm.com
Signed-off-by: Suzuki K. Poulose 
---
 arch/arm/include/asm/kvm_mmu.h   |7 ++
 arch/arm/kvm/mmu.c   |   44 +-
 arch/arm64/include/asm/kvm_mmu.h |   43 +
 3 files changed, 55 insertions(+), 39 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 405aa18..1c9aa8a 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -173,6 +173,13 @@ static inline unsigned int kvm_get_hwpgd_size(void)
return PTRS_PER_S2_PGD * sizeof(pgd_t);
 }
 
+static inline pgd_t *kvm_setup_fake_pgd(pgd_t *pgd)
+{
+   return pgd;
+}
+
+static inline void kvm_free_fake_pgd(pgd_t *pgd) {}
+
 struct kvm;
 
 #define kvm_flush_dcache_to_poc(a,l)   __cpuc_flush_dcache_area((a), (l))
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 7b42012..b210622 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -677,43 +677,11 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm)
 * guest, we allocate a fake PGD and pre-populate it to point
 * to the next-level page table, which will be the real
 * initial page table pointed to by the VTTBR.
-*
-* When KVM_PREALLOC_LEVEL==2, we allocate a single page for
-* the PMD and the kernel will use folded pud.
-* When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
-* pages.
 */
-   if (KVM_PREALLOC_LEVEL > 0) {
-   int i;
-
-   /*
-* Allocate fake pgd for the page table manipulation macros to
-* work.  This is not used by the hardware and we have no
-* alignment requirement for this allocation.
-*/
-   pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
-   GFP_KERNEL | __GFP_ZERO);
-
-   if (!pgd) {
-   kvm_free_hwpgd(hwpgd);
-   return -ENOMEM;
-   }
-
-   /* Plug the HW PGD into the fake one. */
-   for (i = 0; i < PTRS_PER_S2_PGD; i++) {
-   if (KVM_PREALLOC_LEVEL == 1)
-   pgd_populate(NULL, pgd + i,
-(pud_t *)hwpgd + i * PTRS_PER_PUD);
-   else if (KVM_PREALLOC_LEVEL == 2)
-   pud_populate(NULL, pud_offset(pgd, 0) + i,
-(pmd_t *)hwpgd + i * PTRS_PER_PMD);
-   }
-   } else {
-   /*
-* Allocate actual first-level Stage-2 page table used by the
-* hardware for Stage-2 page table walks.
-*/
-   pgd = (pgd_t *)hwpgd;
+   pgd = kvm_setup_fake_pgd(hwpgd);
+   if (IS_ERR(pgd)) {
+   kvm_free_hwpgd(hwpgd);
+   return PTR_ERR(pgd);
}
 
kvm_clean_pgd(pgd);
@@ -820,9 +788,7 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
 
unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
kvm_free_hwpgd(kvm_get_hwpgd(kvm));
-   if (KVM_PREALLOC_LEVEL > 0)
-   kfree(kvm->arch.pgd);
-
+   kvm_free_fake_pgd(kvm->arch.pgd);
kvm->arch.pgd = NULL;
 }
 
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 6150567..2567fe8 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -198,6 +198,49 @@ static inline unsigned int kvm_get_hwpgd_size(void)
return PTRS_PER_S2_PGD * sizeof(pgd_t);
 }
 
+/*
+ * Allocate fake pgd for the page table manipulation macros to
+ * work.  This is not used by the hardware and we have no
+ * alignment requirement for this allocation.
+ */
+static inline pgd_t* kvm_setup_fake_pgd(pgd_t *hwpgd)
+{
+   int i;
+   pgd_t *pgd;
+
+   if (!KVM_PREALLOC_LEVEL)
+   return hwpgd;
+   /*
+* When KVM_PREALLOC_LEVEL==2, we allocate a single page for
+* the PMD and the kernel will use folded pud.
+* When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
+* pages.
+*/
+   pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
+   GFP_KERNEL | __GFP_ZERO);
+
+   if (!pgd)
+   return ERR_PTR(-ENOMEM);
+
+   /* Plug the HW PGD into the fake one. */
+   for (i = 0; i < PTRS_PER_S2_PGD; i++) {
+   if (KVM_PREALLOC_LEVEL == 1)
+   pgd_populate(NULL, pgd + i,
+(pud_t *)hwpgd + i * PTRS_PER_PUD);
+   else if (KVM_PREALLOC_LEVEL == 2)
+