Messages in this thread | | | Subject | Re: [PATCH v5 5/7] KVM: arm64: Support handling access faults for PUD hugepages | From | Suzuki K Poulose <> | Date | Wed, 11 Jul 2018 14:16:56 +0100 |
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On 09/07/18 15:41, Punit Agrawal wrote: > In preparation for creating larger hugepages at Stage 2, extend the > access fault handling at Stage 2 to support PUD hugepages when > encountered. > > Provide trivial helpers for arm32 to allow sharing of code. > > Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> > Cc: Christoffer Dall <christoffer.dall@arm.com> > Cc: Marc Zyngier <marc.zyngier@arm.com> > Cc: Russell King <linux@armlinux.org.uk> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > --- > arch/arm/include/asm/kvm_mmu.h | 8 ++++++++ > arch/arm64/include/asm/kvm_mmu.h | 7 +++++++ > arch/arm64/include/asm/pgtable.h | 6 ++++++ > virt/kvm/arm/mmu.c | 29 ++++++++++++++++------------- > 4 files changed, 37 insertions(+), 13 deletions(-) > > diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h > index d05c8986e495..a4298d429efc 100644 > --- a/arch/arm/include/asm/kvm_mmu.h > +++ b/arch/arm/include/asm/kvm_mmu.h > @@ -78,6 +78,8 @@ void kvm_clear_hyp_idmap(void); > #define kvm_pfn_pte(pfn, prot) pfn_pte(pfn, prot) > #define kvm_pfn_pmd(pfn, prot) pfn_pmd(pfn, prot) > > +#define kvm_pud_pfn(pud) (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
Since we don't have PUD in arm32, it would be good to trigger a BUG() instead of silently doing something wrong.
> @@ -102,6 +104,12 @@ static inline bool kvm_s2pud_exec(pud_t *pud) > return false; > } > > +static inline pud_t kvm_s2pud_mkyoung(pud_t pud) > +{ > + BUG(); > + return pud; > +} > +
Like this. ^
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index e73909a31e02..d2c705e31584 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -1637,33 +1637,36 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > */ > static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) > { > - pmd_t *pmd; > - pte_t *pte; > + pud_t *pud = NULL; > + pmd_t *pmd = NULL; > + pte_t *pte = NULL; > kvm_pfn_t pfn; > - bool pfn_valid = false; > + bool found, pfn_valid = false;
nit: You could use pfn_valid instead of a new "found" variable.
> > trace_kvm_access_fault(fault_ipa); > > spin_lock(&vcpu->kvm->mmu_lock); > > - pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa); > - if (!pmd || pmd_none(*pmd)) /* Nothing there */ > + found = stage2_get_leaf_entry(vcpu->kvm, fault_ipa, &pud, &pmd, &pte); > + if (!found) > goto out; > > - if (pmd_thp_or_huge(*pmd)) { /* THP, HugeTLB */ > + if (pud) { /* HugeTLB */ > + *pud = kvm_s2pud_mkyoung(*pud); > + pfn = kvm_pud_pfn(*pud); > + pfn_valid = true; > + goto out;
You don't need these goto's and the out lable anymore.
> + } else if (pmd) { /* THP, HugeTLB */ > *pmd = pmd_mkyoung(*pmd); > pfn = pmd_pfn(*pmd); > pfn_valid = true; > goto out; > + } else { > + *pte = pte_mkyoung(*pte); /* Just a page... */ > + pfn = pte_pfn(*pte); > + pfn_valid = true; > } > > - pte = pte_offset_kernel(pmd, fault_ipa); > - if (pte_none(*pte)) /* Nothing there either */ > - goto out; > - > - *pte = pte_mkyoung(*pte); /* Just a page... */ > - pfn = pte_pfn(*pte); > - pfn_valid = true; > out: > spin_unlock(&vcpu->kvm->mmu_lock); > if (pfn_valid) >
Otherwise look good to me.
Suzuki
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