| Message ID | 1410990981-665-2-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Sep 17, 2014 at 02:56:16PM -0700, Ard Biesheuvel wrote: > Pass __GFP_ZERO to __get_free_pages() instead of calling memset() > explicitly. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm/kvm/mmu.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > index c68ec28f17c3..152e0f896e63 100644 > --- a/arch/arm/kvm/mmu.c > +++ b/arch/arm/kvm/mmu.c > @@ -528,11 +528,10 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm) > return -EINVAL; > } > > - pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, S2_PGD_ORDER); > + pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, S2_PGD_ORDER); > if (!pgd) > return -ENOMEM; > > - memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t)); > kvm_clean_pgd(pgd); > kvm->arch.pgd = pgd; > So I think the point here was that if you use concatenated first-level page tables, your MMU would only ever look in the first few entries of the first-level page table, and we didn't want to zero-out more memory than necessary. However, there's something to be said for the fact that for sanity, we should probably be clearing out the entire pgd anyhow. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Thanks, -Christoffer
On 17/09/14 22:56, Ard Biesheuvel wrote: > Pass __GFP_ZERO to __get_free_pages() instead of calling memset() > explicitly. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> M. > --- > arch/arm/kvm/mmu.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > index c68ec28f17c3..152e0f896e63 100644 > --- a/arch/arm/kvm/mmu.c > +++ b/arch/arm/kvm/mmu.c > @@ -528,11 +528,10 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm) > return -EINVAL; > } > > - pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, S2_PGD_ORDER); > + pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, S2_PGD_ORDER); > if (!pgd) > return -ENOMEM; > > - memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t)); > kvm_clean_pgd(pgd); > kvm->arch.pgd = pgd; > >
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index c68ec28f17c3..152e0f896e63 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -528,11 +528,10 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm) return -EINVAL; } - pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, S2_PGD_ORDER); + pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, S2_PGD_ORDER); if (!pgd) return -ENOMEM; - memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t)); kvm_clean_pgd(pgd); kvm->arch.pgd = pgd;
Pass __GFP_ZERO to __get_free_pages() instead of calling memset() explicitly. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/kvm/mmu.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)