| Message ID | 1401837567-5527-5-git-send-email-m.smarduch@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 03, 2014 at 04:19:27PM -0700, Mario Smarduch wrote: > This patch adds support for handling 2nd stage page faults during migration, > it disables faulting in huge pages, and disolves huge pages to page tables. s/disolves/dissolves/g > In case migration is canceled huge pages will be used again. > > Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> > --- > arch/arm/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- > 1 file changed, 34 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > index 1c546c9..aca4fbf 100644 > --- a/arch/arm/kvm/mmu.c > +++ b/arch/arm/kvm/mmu.c > @@ -966,6 +966,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; > struct vm_area_struct *vma; > pfn_t pfn; > + /* Get logging status, if dirty_bitmap is not NULL then logging is on */ > + bool logging_active = !!memslot->dirty_bitmap; > > write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); > if (fault_status == FSC_PERM && !write_fault) { > @@ -1019,10 +1021,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > spin_lock(&kvm->mmu_lock); > if (mmu_notifier_retry(kvm, mmu_seq)) > goto out_unlock; > - if (!hugetlb && !force_pte) > + > + /* When logging don't spend cycles to check for huge pages */ drop the comment: either explain the entire clause (which would be too long) or don't explain anything. > + if (!hugetlb && !force_pte && !logging_active) instead of having all this, can't you just change if (is_vm_hugetlb_page(vma)) to if (is_vm_hugetlb_page(vma) && !logging_active) then you're also not mucking around with the gfn etc. > hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); > > - if (hugetlb) { > + /* > + * Force all not present/perm faults to PTE handling, address both > + * PMD and PTE faults > + */ I don't understand this comment? In which case does this apply? > + if (hugetlb && !logging_active) { > pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); > new_pmd = pmd_mkhuge(new_pmd); > if (writable) { > @@ -1034,6 +1042,22 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > } else { > pte_t new_pte = pfn_pte(pfn, PAGE_S2); > if (writable) { > + /* > + * If pmd is mapping a huge page then clear it and let > + * stage2_set_pte() create a pte table. At the sametime > + * you write protect the pte (PAGE_S2 pgprot_t). > + */ > + if (logging_active) { > + pmd_t *pmd; > + if (hugetlb) { > + pfn += pte_index(fault_ipa); > + gfn = fault_ipa >> PAGE_SHIFT; > + new_pte = pfn_pte(pfn, PAGE_S2); > + } > + pmd = stage2_get_pmd(kvm, NULL, fault_ipa); > + if (pmd && kvm_pmd_huge(*pmd)) > + clear_pmd_entry(kvm, pmd, fault_ipa); > + } now instead of all this, you just need to check for kvm_pmd_huge() in stage2_set_pte() and if that's true, you clear it, and then then install your new pte. > kvm_set_s2pte_writable(&new_pte); > kvm_set_pfn_dirty(pfn); > } > @@ -1041,6 +1065,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); > } > > + /* > + * Log the dirty page in dirty_bitmap[], call regardless if logging is > + * disabled or enabled both cases handled safely. > + * TODO: for larger page size mark mulitple dirty page bits for each > + * 4k page. > + */ > + if (writable) > + mark_page_dirty(kvm, gfn); what if you just faulted in a page on a read which wasn't present before but it happens to belong to a writeable memslot, is that page then dirty? hmmm. > > out_unlock: > spin_unlock(&kvm->mmu_lock); > -- > 1.7.9.5 > Thanks, -Christoffer -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/08/2014 05:05 AM, Christoffer Dall wrote: > On Tue, Jun 03, 2014 at 04:19:27PM -0700, Mario Smarduch wrote: >> This patch adds support for handling 2nd stage page faults during migration, >> it disables faulting in huge pages, and disolves huge pages to page tables. > > s/disolves/dissolves/g Will do. > >> In case migration is canceled huge pages will be used again. >> >> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> >> --- >> arch/arm/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- >> 1 file changed, 34 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c >> index 1c546c9..aca4fbf 100644 >> --- a/arch/arm/kvm/mmu.c >> +++ b/arch/arm/kvm/mmu.c >> @@ -966,6 +966,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; >> struct vm_area_struct *vma; >> pfn_t pfn; >> + /* Get logging status, if dirty_bitmap is not NULL then logging is on */ >> + bool logging_active = !!memslot->dirty_bitmap; > >> >> write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); >> if (fault_status == FSC_PERM && !write_fault) { >> @@ -1019,10 +1021,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> spin_lock(&kvm->mmu_lock); >> if (mmu_notifier_retry(kvm, mmu_seq)) >> goto out_unlock; >> - if (!hugetlb && !force_pte) >> + >> + /* When logging don't spend cycles to check for huge pages */ > > drop the comment: either explain the entire clause (which would be too > long) or don't explain anything. > Ok. >> + if (!hugetlb && !force_pte && !logging_active) > > instead of having all this, can't you just change > > if (is_vm_hugetlb_page(vma)) to > if (is_vm_hugetlb_page(vma) && !logging_active) > > then you're also not mucking around with the gfn etc. I didn't want to modify this function too much, but if that's ok that simplifies things a lot. > >> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); >> >> - if (hugetlb) { >> + /* >> + * Force all not present/perm faults to PTE handling, address both >> + * PMD and PTE faults >> + */ > > I don't understand this comment? In which case does this apply? > The cases I see here - - huge page permission fault is forced into page table code while logging - pte permission/not present handled by page table code as before. >> + if (hugetlb && !logging_active) { >> pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); >> new_pmd = pmd_mkhuge(new_pmd); >> if (writable) { >> @@ -1034,6 +1042,22 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> } else { >> pte_t new_pte = pfn_pte(pfn, PAGE_S2); >> if (writable) { >> + /* >> + * If pmd is mapping a huge page then clear it and let >> + * stage2_set_pte() create a pte table. At the sametime >> + * you write protect the pte (PAGE_S2 pgprot_t). >> + */ >> + if (logging_active) { >> + pmd_t *pmd; >> + if (hugetlb) { >> + pfn += pte_index(fault_ipa); >> + gfn = fault_ipa >> PAGE_SHIFT; >> + new_pte = pfn_pte(pfn, PAGE_S2); >> + } >> + pmd = stage2_get_pmd(kvm, NULL, fault_ipa); >> + if (pmd && kvm_pmd_huge(*pmd)) >> + clear_pmd_entry(kvm, pmd, fault_ipa); >> + } > > now instead of all this, you just need to check for kvm_pmd_huge() in > stage2_set_pte() and if that's true, you clear it, and then then install > your new pte. Yes this really simplifies things! > >> kvm_set_s2pte_writable(&new_pte); >> kvm_set_pfn_dirty(pfn); >> } >> @@ -1041,6 +1065,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >> ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); >> } >> >> + /* >> + * Log the dirty page in dirty_bitmap[], call regardless if logging is >> + * disabled or enabled both cases handled safely. >> + * TODO: for larger page size mark mulitple dirty page bits for each >> + * 4k page. >> + */ >> + if (writable) >> + mark_page_dirty(kvm, gfn); > > what if you just faulted in a page on a read which wasn't present > before but it happens to belong to a writeable memslot, is that page > then dirty? hmmm. > A bug, must also check if it was a write fault not just that we're dealing with a writable region. This one could be pretty bad on performance, not to mention in accurate. It will be interesting to see new test results, glad you caught that. Thanks, Mario. > >> >> out_unlock: >> spin_unlock(&kvm->mmu_lock); >> -- >> 1.7.9.5 >> > > Thanks, > -Christoffer > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jun 10, 2014 at 11:23:17AM -0700, Mario Smarduch wrote: > On 06/08/2014 05:05 AM, Christoffer Dall wrote: > > On Tue, Jun 03, 2014 at 04:19:27PM -0700, Mario Smarduch wrote: > >> This patch adds support for handling 2nd stage page faults during migration, > >> it disables faulting in huge pages, and disolves huge pages to page tables. > > > > s/disolves/dissolves/g > Will do. > > > >> In case migration is canceled huge pages will be used again. > >> > >> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> > >> --- > >> arch/arm/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- > >> 1 file changed, 34 insertions(+), 2 deletions(-) > >> > >> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > >> index 1c546c9..aca4fbf 100644 > >> --- a/arch/arm/kvm/mmu.c > >> +++ b/arch/arm/kvm/mmu.c > >> @@ -966,6 +966,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > >> struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; > >> struct vm_area_struct *vma; > >> pfn_t pfn; > >> + /* Get logging status, if dirty_bitmap is not NULL then logging is on */ > >> + bool logging_active = !!memslot->dirty_bitmap; > > > >> > >> write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); > >> if (fault_status == FSC_PERM && !write_fault) { > >> @@ -1019,10 +1021,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > >> spin_lock(&kvm->mmu_lock); > >> if (mmu_notifier_retry(kvm, mmu_seq)) > >> goto out_unlock; > >> - if (!hugetlb && !force_pte) > >> + > >> + /* When logging don't spend cycles to check for huge pages */ > > > > drop the comment: either explain the entire clause (which would be too > > long) or don't explain anything. > > > Ok. > >> + if (!hugetlb && !force_pte && !logging_active) > > > > instead of having all this, can't you just change > > > > if (is_vm_hugetlb_page(vma)) to > > if (is_vm_hugetlb_page(vma) && !logging_active) > > > > then you're also not mucking around with the gfn etc. > > I didn't want to modify this function too much, but if that's ok that > simplifies things a lot. > Don't worry about the changes as much as the resulting code. If something requires a lot of refactoring, usually that can be handled by splitting up renames, factoring out functions, etc. into multiple smaller patches. > > > >> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); > >> > >> - if (hugetlb) { > >> + /* > >> + * Force all not present/perm faults to PTE handling, address both > >> + * PMD and PTE faults > >> + */ > > > > I don't understand this comment? In which case does this apply? > > > The cases I see here - > - huge page permission fault is forced into page table code while logging > - pte permission/not present handled by page table code as before. Hmm, the wording doesn't really work for me. I don't think this comment adds anything or is required, when getting this deep into the fault handler etc., one better understand what's going on. The most suitable place for a comment in this work is probably in stage2_set_pte() where you can now detect a kvm_pmd_huge(), when you add that, you may want to add a small comment that this only happens when logging dirty pages. > >> + if (hugetlb && !logging_active) { > >> pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); > >> new_pmd = pmd_mkhuge(new_pmd); > >> if (writable) { > >> @@ -1034,6 +1042,22 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > >> } else { > >> pte_t new_pte = pfn_pte(pfn, PAGE_S2); > >> if (writable) { > >> + /* > >> + * If pmd is mapping a huge page then clear it and let > >> + * stage2_set_pte() create a pte table. At the sametime > >> + * you write protect the pte (PAGE_S2 pgprot_t). > >> + */ > >> + if (logging_active) { > >> + pmd_t *pmd; > >> + if (hugetlb) { > >> + pfn += pte_index(fault_ipa); > >> + gfn = fault_ipa >> PAGE_SHIFT; > >> + new_pte = pfn_pte(pfn, PAGE_S2); > >> + } > >> + pmd = stage2_get_pmd(kvm, NULL, fault_ipa); > >> + if (pmd && kvm_pmd_huge(*pmd)) > >> + clear_pmd_entry(kvm, pmd, fault_ipa); > >> + } > > > > now instead of all this, you just need to check for kvm_pmd_huge() in > > stage2_set_pte() and if that's true, you clear it, and then then install > > your new pte. > > Yes this really simplifies things! > > > > >> kvm_set_s2pte_writable(&new_pte); > >> kvm_set_pfn_dirty(pfn); > >> } > >> @@ -1041,6 +1065,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > >> ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); > >> } > >> > >> + /* > >> + * Log the dirty page in dirty_bitmap[], call regardless if logging is > >> + * disabled or enabled both cases handled safely. > >> + * TODO: for larger page size mark mulitple dirty page bits for each > >> + * 4k page. > >> + */ > >> + if (writable) > >> + mark_page_dirty(kvm, gfn); > > > > what if you just faulted in a page on a read which wasn't present > > before but it happens to belong to a writeable memslot, is that page > > then dirty? hmmm. > > > A bug, must also check if it was a write fault not just that we're dealing with > a writable region. This one could be pretty bad on performance, not to mention > in accurate. It will be interesting to see new test results, glad you caught > that. > ok, please fix. Thanks, -Christoffer -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/10/2014 11:58 PM, Christoffer Dall wrote: > On Tue, Jun 10, 2014 at 11:23:17AM -0700, Mario Smarduch wrote: >> On 06/08/2014 05:05 AM, Christoffer Dall wrote: >>> On Tue, Jun 03, 2014 at 04:19:27PM -0700, Mario Smarduch wrote: >>>> This patch adds support for handling 2nd stage page faults during migration, >>>> it disables faulting in huge pages, and disolves huge pages to page tables. >>> >>> s/disolves/dissolves/g >> Will do. >>> >>>> In case migration is canceled huge pages will be used again. >>>> >>>> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> >>>> --- >>>> arch/arm/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- >>>> 1 file changed, 34 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c >>>> index 1c546c9..aca4fbf 100644 >>>> --- a/arch/arm/kvm/mmu.c >>>> +++ b/arch/arm/kvm/mmu.c >>>> @@ -966,6 +966,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >>>> struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; >>>> struct vm_area_struct *vma; >>>> pfn_t pfn; >>>> + /* Get logging status, if dirty_bitmap is not NULL then logging is on */ >>>> + bool logging_active = !!memslot->dirty_bitmap; >>> >>>> >>>> write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); >>>> if (fault_status == FSC_PERM && !write_fault) { >>>> @@ -1019,10 +1021,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >>>> spin_lock(&kvm->mmu_lock); >>>> if (mmu_notifier_retry(kvm, mmu_seq)) >>>> goto out_unlock; >>>> - if (!hugetlb && !force_pte) >>>> + >>>> + /* When logging don't spend cycles to check for huge pages */ >>> >>> drop the comment: either explain the entire clause (which would be too >>> long) or don't explain anything. >>> >> Ok. >>>> + if (!hugetlb && !force_pte && !logging_active) >>> >>> instead of having all this, can't you just change >>> >>> if (is_vm_hugetlb_page(vma)) to >>> if (is_vm_hugetlb_page(vma) && !logging_active) >>> >>> then you're also not mucking around with the gfn etc. >> >> I didn't want to modify this function too much, but if that's ok that >> simplifies things a lot. >> > > Don't worry about the changes as much as the resulting code. If > something requires a lot of refactoring, usually that can be handled by > splitting up renames, factoring out functions, etc. into multiple > smaller patches. > >>> >>>> hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); >>>> >>>> - if (hugetlb) { >>>> + /* >>>> + * Force all not present/perm faults to PTE handling, address both >>>> + * PMD and PTE faults >>>> + */ >>> >>> I don't understand this comment? In which case does this apply? >>> >> The cases I see here - >> - huge page permission fault is forced into page table code while logging >> - pte permission/not present handled by page table code as before. > > Hmm, the wording doesn't really work for me. I don't think this comment > adds anything or is required, when getting this deep into the fault > handler etc., one better understand what's going on. > > The most suitable place for a comment in this work is probably in > stage2_set_pte() where you can now detect a kvm_pmd_huge(), when you add > that, you may want to add a small comment that this only happens when > logging dirty pages. > >>>> + if (hugetlb && !logging_active) { >>>> pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); >>>> new_pmd = pmd_mkhuge(new_pmd); >>>> if (writable) { >>>> @@ -1034,6 +1042,22 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >>>> } else { >>>> pte_t new_pte = pfn_pte(pfn, PAGE_S2); >>>> if (writable) { >>>> + /* >>>> + * If pmd is mapping a huge page then clear it and let >>>> + * stage2_set_pte() create a pte table. At the sametime >>>> + * you write protect the pte (PAGE_S2 pgprot_t). >>>> + */ >>>> + if (logging_active) { >>>> + pmd_t *pmd; >>>> + if (hugetlb) { >>>> + pfn += pte_index(fault_ipa); >>>> + gfn = fault_ipa >> PAGE_SHIFT; >>>> + new_pte = pfn_pte(pfn, PAGE_S2); >>>> + } >>>> + pmd = stage2_get_pmd(kvm, NULL, fault_ipa); >>>> + if (pmd && kvm_pmd_huge(*pmd)) >>>> + clear_pmd_entry(kvm, pmd, fault_ipa); >>>> + } >>> >>> now instead of all this, you just need to check for kvm_pmd_huge() in >>> stage2_set_pte() and if that's true, you clear it, and then then install >>> your new pte. >> >> Yes this really simplifies things! >> >>> >>>> kvm_set_s2pte_writable(&new_pte); >>>> kvm_set_pfn_dirty(pfn); >>>> } >>>> @@ -1041,6 +1065,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, >>>> ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); >>>> } >>>> >>>> + /* >>>> + * Log the dirty page in dirty_bitmap[], call regardless if logging is >>>> + * disabled or enabled both cases handled safely. >>>> + * TODO: for larger page size mark mulitple dirty page bits for each >>>> + * 4k page. >>>> + */ >>>> + if (writable) >>>> + mark_page_dirty(kvm, gfn); >>> >>> what if you just faulted in a page on a read which wasn't present >>> before but it happens to belong to a writeable memslot, is that page >>> then dirty? hmmm. >>> >> A bug, must also check if it was a write fault not just that we're dealing with >> a writable region. This one could be pretty bad on performance, not to mention >> in accurate. It will be interesting to see new test results, glad you caught >> that. >> > ok, please fix. > > Thanks, > -Christoffer > So I'll start on next iteration, make sure it builds cleanly on all the architecture. Follow up with Paolo on how to handle the generic functions. I think arm64 will need some extra work. - Mario -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 1c546c9..aca4fbf 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -966,6 +966,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; struct vm_area_struct *vma; pfn_t pfn; + /* Get logging status, if dirty_bitmap is not NULL then logging is on */ + bool logging_active = !!memslot->dirty_bitmap; write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); if (fault_status == FSC_PERM && !write_fault) { @@ -1019,10 +1021,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, spin_lock(&kvm->mmu_lock); if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; - if (!hugetlb && !force_pte) + + /* When logging don't spend cycles to check for huge pages */ + if (!hugetlb && !force_pte && !logging_active) hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); - if (hugetlb) { + /* + * Force all not present/perm faults to PTE handling, address both + * PMD and PTE faults + */ + if (hugetlb && !logging_active) { pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); new_pmd = pmd_mkhuge(new_pmd); if (writable) { @@ -1034,6 +1042,22 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, } else { pte_t new_pte = pfn_pte(pfn, PAGE_S2); if (writable) { + /* + * If pmd is mapping a huge page then clear it and let + * stage2_set_pte() create a pte table. At the sametime + * you write protect the pte (PAGE_S2 pgprot_t). + */ + if (logging_active) { + pmd_t *pmd; + if (hugetlb) { + pfn += pte_index(fault_ipa); + gfn = fault_ipa >> PAGE_SHIFT; + new_pte = pfn_pte(pfn, PAGE_S2); + } + pmd = stage2_get_pmd(kvm, NULL, fault_ipa); + if (pmd && kvm_pmd_huge(*pmd)) + clear_pmd_entry(kvm, pmd, fault_ipa); + } kvm_set_s2pte_writable(&new_pte); kvm_set_pfn_dirty(pfn); } @@ -1041,6 +1065,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); } + /* + * Log the dirty page in dirty_bitmap[], call regardless if logging is + * disabled or enabled both cases handled safely. + * TODO: for larger page size mark mulitple dirty page bits for each + * 4k page. + */ + if (writable) + mark_page_dirty(kvm, gfn); out_unlock: spin_unlock(&kvm->mmu_lock);
This patch adds support for handling 2nd stage page faults during migration, it disables faulting in huge pages, and disolves huge pages to page tables. In case migration is canceled huge pages will be used again. Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> --- arch/arm/kvm/mmu.c | 36 ++++++++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-)