| Message ID | 20180705140850.5801-2-punit.agrawal@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Punit, On 05/07/18 15:08, Punit Agrawal wrote: > The code for operations such as marking the pfn as dirty, and > dcache/icache maintenance during stage 2 fault handling is duplicated > between normal pages and PMD hugepages. > > Instead of creating another copy of the operations when we introduce > PUD hugepages, let's share them across the different pagesizes. > > Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> > Cc: Christoffer Dall <christoffer.dall@arm.com> > Cc: Marc Zyngier <marc.zyngier@arm.com> > --- > virt/kvm/arm/mmu.c | 68 +++++++++++++++++++++++++++------------------- > 1 file changed, 40 insertions(+), 28 deletions(-) > > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index 1d90d79706bd..dd14cc36c51c 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -1398,6 +1398,21 @@ static void invalidate_icache_guest_page(kvm_pfn_t pfn, unsigned long size) > __invalidate_icache_guest_page(pfn, size); > } > > +static bool stage2_should_exec(struct kvm *kvm, phys_addr_t addr, > + bool exec_fault, unsigned long fault_status) I find this "should exec" very confusing. > +{ > + /* > + * If we took an execution fault we will have made the > + * icache/dcache coherent and should now let the s2 mapping be > + * executable. > + * > + * Write faults (!exec_fault && FSC_PERM) are orthogonal to > + * execute permissions, and we preserve whatever we have. > + */ > + return exec_fault || > + (fault_status == FSC_PERM && stage2_is_exec(kvm, addr)); > +} > + > static void kvm_send_hwpoison_signal(unsigned long address, > struct vm_area_struct *vma) > { > @@ -1431,7 +1446,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > kvm_pfn_t pfn; > pgprot_t mem_type = PAGE_S2; > bool logging_active = memslot_is_logging(memslot); > - unsigned long flags = 0; > + unsigned long vma_pagesize, flags = 0; > > write_fault = kvm_is_write_fault(vcpu); > exec_fault = kvm_vcpu_trap_is_iabt(vcpu); > @@ -1451,7 +1466,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > return -EFAULT; > } > > - if (vma_kernel_pagesize(vma) == PMD_SIZE && !logging_active) { > + vma_pagesize = vma_kernel_pagesize(vma); > + if (vma_pagesize == PMD_SIZE && !logging_active) { > hugetlb = true; > gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; > } else { > @@ -1520,28 +1536,34 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > if (mmu_notifier_retry(kvm, mmu_seq)) > goto out_unlock; > > - if (!hugetlb && !force_pte) > + if (!hugetlb && !force_pte) { > + /* > + * Only PMD_SIZE transparent hugepages(THP) are > + * currently supported. This code will need to be > + * updated to support other THP sizes. > + */ > hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); > + if (hugetlb) > + vma_pagesize = PMD_SIZE; > + } > + > + if (writable) > + kvm_set_pfn_dirty(pfn); > > - if (hugetlb) { > + if (fault_status != FSC_PERM) > + clean_dcache_guest_page(pfn, vma_pagesize); > + > + if (exec_fault) > + invalidate_icache_guest_page(pfn, vma_pagesize); > + > + if (hugetlb && vma_pagesize == PMD_SIZE) { > pmd_t new_pmd = pfn_pmd(pfn, mem_type); > new_pmd = pmd_mkhuge(new_pmd); > - if (writable) { > + if (writable) > new_pmd = kvm_s2pmd_mkwrite(new_pmd); > - kvm_set_pfn_dirty(pfn); > - } > > - if (fault_status != FSC_PERM) > - clean_dcache_guest_page(pfn, PMD_SIZE); > - > - if (exec_fault) { > + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) > new_pmd = kvm_s2pmd_mkexec(new_pmd); OK, I find this absolutely horrid... ;-) The rest of the function deals with discrete flags, and all of a sudden we have a function call with a bunch of seemingly unrelated parameters. And you are repeating it for each vma_pagesize... How about something like: bool needs_exec; [...] needs_exec = exec_fault || (fault_status == FSC_PERM && stage2_is_exec(kvm, fault_ipa); And then you just check needs_exec to update the pte/pmd. And you drop this helper. > - invalidate_icache_guest_page(pfn, PMD_SIZE); > - } else if (fault_status == FSC_PERM) { > - /* Preserve execute if XN was already cleared */ > - if (stage2_is_exec(kvm, fault_ipa)) > - new_pmd = kvm_s2pmd_mkexec(new_pmd); > - } > > ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); > } else { > @@ -1549,21 +1571,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > > if (writable) { > new_pte = kvm_s2pte_mkwrite(new_pte); > - kvm_set_pfn_dirty(pfn); > mark_page_dirty(kvm, gfn); > } > > - if (fault_status != FSC_PERM) > - clean_dcache_guest_page(pfn, PAGE_SIZE); > - > - if (exec_fault) { > + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) > new_pte = kvm_s2pte_mkexec(new_pte); > - invalidate_icache_guest_page(pfn, PAGE_SIZE); > - } else if (fault_status == FSC_PERM) { > - /* Preserve execute if XN was already cleared */ > - if (stage2_is_exec(kvm, fault_ipa)) > - new_pte = kvm_s2pte_mkexec(new_pte); > - } > > ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags); > } > Thanks, M.
Marc Zyngier <marc.zyngier@arm.com> writes: > Hi Punit, > > On 05/07/18 15:08, Punit Agrawal wrote: >> The code for operations such as marking the pfn as dirty, and >> dcache/icache maintenance during stage 2 fault handling is duplicated >> between normal pages and PMD hugepages. >> >> Instead of creating another copy of the operations when we introduce >> PUD hugepages, let's share them across the different pagesizes. >> >> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> >> Cc: Christoffer Dall <christoffer.dall@arm.com> >> Cc: Marc Zyngier <marc.zyngier@arm.com> >> --- >> virt/kvm/arm/mmu.c | 68 +++++++++++++++++++++++++++------------------- >> 1 file changed, 40 insertions(+), 28 deletions(-) >> >> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c >> index 1d90d79706bd..dd14cc36c51c 100644 >> --- a/virt/kvm/arm/mmu.c >> +++ b/virt/kvm/arm/mmu.c >> @@ -1398,6 +1398,21 @@ static void invalidate_icache_guest_page(kvm_pfn_t pfn, unsigned long size) >> __invalidate_icache_guest_page(pfn, size); >> } >> >> +static bool stage2_should_exec(struct kvm *kvm, phys_addr_t addr, >> + bool exec_fault, unsigned long fault_status) > > I find this "should exec" very confusing. > >> +{ >> + /* >> + * If we took an execution fault we will have made the >> + * icache/dcache coherent and should now let the s2 mapping be >> + * executable. >> + * >> + * Write faults (!exec_fault && FSC_PERM) are orthogonal to >> + * execute permissions, and we preserve whatever we have. >> + */ >> + return exec_fault || >> + (fault_status == FSC_PERM && stage2_is_exec(kvm, addr)); >> +} >> + >> static void kvm_send_hwpoison_signal(unsigned long address, >> struct vm_area_struct *vma) >> { >> @@ -1431,7 +1446,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> kvm_pfn_t pfn; >> pgprot_t mem_type = PAGE_S2; >> bool logging_active = memslot_is_logging(memslot); >> - unsigned long flags = 0; >> + unsigned long vma_pagesize, flags = 0; >> >> write_fault = kvm_is_write_fault(vcpu); >> exec_fault = kvm_vcpu_trap_is_iabt(vcpu); >> @@ -1451,7 +1466,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> return -EFAULT; >> } >> >> - if (vma_kernel_pagesize(vma) == PMD_SIZE && !logging_active) { >> + vma_pagesize = vma_kernel_pagesize(vma); >> + if (vma_pagesize == PMD_SIZE && !logging_active) { >> hugetlb = true; >> gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; >> } else { >> @@ -1520,28 +1536,34 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> if (mmu_notifier_retry(kvm, mmu_seq)) >> goto out_unlock; >> >> - if (!hugetlb && !force_pte) >> + if (!hugetlb && !force_pte) { >> + /* >> + * Only PMD_SIZE transparent hugepages(THP) are >> + * currently supported. This code will need to be >> + * updated to support other THP sizes. >> + */ >> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); >> + if (hugetlb) >> + vma_pagesize = PMD_SIZE; >> + } >> + >> + if (writable) >> + kvm_set_pfn_dirty(pfn); >> >> - if (hugetlb) { >> + if (fault_status != FSC_PERM) >> + clean_dcache_guest_page(pfn, vma_pagesize); >> + >> + if (exec_fault) >> + invalidate_icache_guest_page(pfn, vma_pagesize); >> + >> + if (hugetlb && vma_pagesize == PMD_SIZE) { >> pmd_t new_pmd = pfn_pmd(pfn, mem_type); >> new_pmd = pmd_mkhuge(new_pmd); >> - if (writable) { >> + if (writable) >> new_pmd = kvm_s2pmd_mkwrite(new_pmd); >> - kvm_set_pfn_dirty(pfn); >> - } >> >> - if (fault_status != FSC_PERM) >> - clean_dcache_guest_page(pfn, PMD_SIZE); >> - >> - if (exec_fault) { >> + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) >> new_pmd = kvm_s2pmd_mkexec(new_pmd); > > OK, I find this absolutely horrid... ;-) > > The rest of the function deals with discrete flags, and all of a sudden > we have a function call with a bunch of seemingly unrelated parameters. > And you are repeating it for each vma_pagesize... > > How about something like: > > bool needs_exec; > > [...] > > needs_exec = exec_fault || (fault_status == FSC_PERM && > stage2_is_exec(kvm, fault_ipa); > > And then you just check needs_exec to update the pte/pmd. And you drop > this helper. That does look a lot better. I'll roll the change into the next version. Thanks, Punit [...]
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 1d90d79706bd..dd14cc36c51c 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1398,6 +1398,21 @@ static void invalidate_icache_guest_page(kvm_pfn_t pfn, unsigned long size) __invalidate_icache_guest_page(pfn, size); } +static bool stage2_should_exec(struct kvm *kvm, phys_addr_t addr, + bool exec_fault, unsigned long fault_status) +{ + /* + * If we took an execution fault we will have made the + * icache/dcache coherent and should now let the s2 mapping be + * executable. + * + * Write faults (!exec_fault && FSC_PERM) are orthogonal to + * execute permissions, and we preserve whatever we have. + */ + return exec_fault || + (fault_status == FSC_PERM && stage2_is_exec(kvm, addr)); +} + static void kvm_send_hwpoison_signal(unsigned long address, struct vm_area_struct *vma) { @@ -1431,7 +1446,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, kvm_pfn_t pfn; pgprot_t mem_type = PAGE_S2; bool logging_active = memslot_is_logging(memslot); - unsigned long flags = 0; + unsigned long vma_pagesize, flags = 0; write_fault = kvm_is_write_fault(vcpu); exec_fault = kvm_vcpu_trap_is_iabt(vcpu); @@ -1451,7 +1466,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, return -EFAULT; } - if (vma_kernel_pagesize(vma) == PMD_SIZE && !logging_active) { + vma_pagesize = vma_kernel_pagesize(vma); + if (vma_pagesize == PMD_SIZE && !logging_active) { hugetlb = true; gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; } else { @@ -1520,28 +1536,34 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; - if (!hugetlb && !force_pte) + if (!hugetlb && !force_pte) { + /* + * Only PMD_SIZE transparent hugepages(THP) are + * currently supported. This code will need to be + * updated to support other THP sizes. + */ hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); + if (hugetlb) + vma_pagesize = PMD_SIZE; + } + + if (writable) + kvm_set_pfn_dirty(pfn); - if (hugetlb) { + if (fault_status != FSC_PERM) + clean_dcache_guest_page(pfn, vma_pagesize); + + if (exec_fault) + invalidate_icache_guest_page(pfn, vma_pagesize); + + if (hugetlb && vma_pagesize == PMD_SIZE) { pmd_t new_pmd = pfn_pmd(pfn, mem_type); new_pmd = pmd_mkhuge(new_pmd); - if (writable) { + if (writable) new_pmd = kvm_s2pmd_mkwrite(new_pmd); - kvm_set_pfn_dirty(pfn); - } - if (fault_status != FSC_PERM) - clean_dcache_guest_page(pfn, PMD_SIZE); - - if (exec_fault) { + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) new_pmd = kvm_s2pmd_mkexec(new_pmd); - invalidate_icache_guest_page(pfn, PMD_SIZE); - } else if (fault_status == FSC_PERM) { - /* Preserve execute if XN was already cleared */ - if (stage2_is_exec(kvm, fault_ipa)) - new_pmd = kvm_s2pmd_mkexec(new_pmd); - } ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); } else { @@ -1549,21 +1571,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (writable) { new_pte = kvm_s2pte_mkwrite(new_pte); - kvm_set_pfn_dirty(pfn); mark_page_dirty(kvm, gfn); } - if (fault_status != FSC_PERM) - clean_dcache_guest_page(pfn, PAGE_SIZE); - - if (exec_fault) { + if (stage2_should_exec(kvm, fault_ipa, exec_fault, fault_status)) new_pte = kvm_s2pte_mkexec(new_pte); - invalidate_icache_guest_page(pfn, PAGE_SIZE); - } else if (fault_status == FSC_PERM) { - /* Preserve execute if XN was already cleared */ - if (stage2_is_exec(kvm, fault_ipa)) - new_pte = kvm_s2pte_mkexec(new_pte); - } ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags); }
The code for operations such as marking the pfn as dirty, and dcache/icache maintenance during stage 2 fault handling is duplicated between normal pages and PMD hugepages. Instead of creating another copy of the operations when we introduce PUD hugepages, let's share them across the different pagesizes. Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/mmu.c | 68 +++++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 28 deletions(-)