Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752460Ab3GFPP4 (ORCPT ); Sat, 6 Jul 2013 11:15:56 -0400 Received: from mail-yh0-f41.google.com ([209.85.213.41]:47476 "EHLO mail-yh0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119Ab3GFPPy (ORCPT ); Sat, 6 Jul 2013 11:15:54 -0400 X-Greylist: delayed 510 seconds by postgrey-1.27 at vger.kernel.org; Sat, 06 Jul 2013 11:15:54 EDT From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , David Gibson , Benjamin Herrenschmidt , Paul Mackerras , Alexander Graf , Alex Williamson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org Subject: [PATCH 8/8] KVM: PPC: Add hugepage support for IOMMU in-kernel handling Date: Sun, 7 Jul 2013 01:07:07 +1000 Message-Id: <1373123227-22969-9-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1373123227-22969-1-git-send-email-aik@ozlabs.ru> References: <1373123227-22969-1-git-send-email-aik@ozlabs.ru> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 12662 Lines: 377 This adds special support for huge pages (16MB). The reference counting cannot be easily done for such pages in real mode (when MMU is off) so we added a list of huge pages. It is populated in virtual mode and get_page is called just once per a huge page. Real mode handlers check if the requested page is huge and in the list, then no reference counting is done, otherwise an exit to virtual mode happens. The list is released at KVM exit. At the moment the fastest card available for tests uses up to 9 huge pages so walking through this list is not very expensive. However this can change and we may want to optimize this. Signed-off-by: Paul Mackerras Signed-off-by: Alexey Kardashevskiy --- Changes: 2013/06/27: * list of huge pages replaces with hashtable for better performance * spinlock removed from real mode and only protects insertion of new huge [ages descriptors into the hashtable 2013/06/05: * fixed compile error when CONFIG_IOMMU_API=n 2013/05/20: * the real mode handler now searches for a huge page by gpa (used to be pte) * the virtual mode handler prints warning if it is called twice for the same huge page as the real mode handler is expected to fail just once - when a huge page is not in the list yet. * the huge page is refcounted twice - when added to the hugepage list and when used in the virtual mode hcall handler (can be optimized but it will make the patch less nice). Signed-off-by: Alexey Kardashevskiy --- arch/powerpc/include/asm/kvm_host.h | 25 +++++++++ arch/powerpc/kernel/iommu.c | 6 ++- arch/powerpc/kvm/book3s_64_vio.c | 104 +++++++++++++++++++++++++++++++++--- arch/powerpc/kvm/book3s_64_vio_hv.c | 21 ++++++-- 4 files changed, 146 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 53e61b2..a7508cf 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -182,10 +183,34 @@ struct kvmppc_spapr_tce_table { u32 window_size; struct iommu_group *grp; /* used for IOMMU groups */ struct vfio_group *vfio_grp; /* used for IOMMU groups */ + DECLARE_HASHTABLE(hash_tab, ilog2(64)); /* used for IOMMU groups */ + spinlock_t hugepages_write_lock; /* used for IOMMU groups */ struct { struct { unsigned long put, indir, stuff; } rm, vm; } stat; struct page *pages[0]; }; +/* + * The KVM guest can be backed with 16MB pages. + * In this case, we cannot do page counting from the real mode + * as the compound pages are used - they are linked in a list + * with pointers as virtual addresses which are inaccessible + * in real mode. + * + * The code below keeps a 16MB pages list and uses page struct + * in real mode if it is already locked in RAM and inserted into + * the list or switches to the virtual mode where it can be + * handled in a usual manner. + */ +#define KVMPPC_SPAPR_HUGEPAGE_HASH(gpa) hash_32(gpa >> 24, 32) + +struct kvmppc_spapr_iommu_hugepage { + struct hlist_node hash_node; + unsigned long gpa; /* Guest physical address */ + unsigned long hpa; /* Host physical address */ + struct page *page; /* page struct of the very first subpage */ + unsigned long size; /* Huge page size (always 16MB at the moment) */ +}; + struct kvmppc_linear_info { void *base_virt; unsigned long base_pfn; diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 51678ec..e0b6eca 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -999,7 +999,8 @@ int iommu_free_tces(struct iommu_table *tbl, unsigned long entry, if (!pg) { ret = -EAGAIN; } else if (PageCompound(pg)) { - ret = -EAGAIN; + /* Hugepages will be released at KVM exit */ + ret = 0; } else { if (oldtce & TCE_PCI_WRITE) SetPageDirty(pg); @@ -1009,6 +1010,9 @@ int iommu_free_tces(struct iommu_table *tbl, unsigned long entry, struct page *pg = pfn_to_page(oldtce >> PAGE_SHIFT); if (!pg) { ret = -EAGAIN; + } else if (PageCompound(pg)) { + /* Hugepages will be released at KVM exit */ + ret = 0; } else { if (oldtce & TCE_PCI_WRITE) SetPageDirty(pg); diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 2b51f4a..c037219 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -46,6 +46,40 @@ #define ERROR_ADDR ((void *)~(unsigned long)0x0) +#ifdef CONFIG_IOMMU_API +static void kvmppc_iommu_hugepages_init(struct kvmppc_spapr_tce_table *tt) +{ + spin_lock_init(&tt->hugepages_write_lock); + hash_init(tt->hash_tab); +} + +static void kvmppc_iommu_hugepages_cleanup(struct kvmppc_spapr_tce_table *tt) +{ + int bkt; + struct kvmppc_spapr_iommu_hugepage *hp; + struct hlist_node *tmp; + + spin_lock(&tt->hugepages_write_lock); + hash_for_each_safe(tt->hash_tab, bkt, tmp, hp, hash_node) { + pr_debug("Release HP liobn=%llx #%u gpa=%lx hpa=%lx size=%ld\n", + tt->liobn, bkt, hp->gpa, hp->hpa, hp->size); + hlist_del_rcu(&hp->hash_node); + + put_page(hp->page); + kfree(hp); + } + spin_unlock(&tt->hugepages_write_lock); +} +#else +static void kvmppc_iommu_hugepages_init(struct kvmppc_spapr_tce_table *tt) +{ +} + +static void kvmppc_iommu_hugepages_cleanup(struct kvmppc_spapr_tce_table *tt) +{ +} +#endif /* CONFIG_IOMMU_API */ + static long kvmppc_stt_npages(unsigned long window_size) { return ALIGN((window_size >> SPAPR_TCE_SHIFT) @@ -112,6 +146,7 @@ static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt) mutex_lock(&kvm->lock); list_del(&stt->list); + kvmppc_iommu_hugepages_cleanup(stt); #ifdef CONFIG_IOMMU_API if (stt->grp) { @@ -200,6 +235,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, kvm_get_kvm(kvm); mutex_lock(&kvm->lock); + kvmppc_iommu_hugepages_init(stt); list_add(&stt->list, &kvm->arch.spapr_tce_tables); mutex_unlock(&kvm->lock); @@ -283,6 +319,7 @@ long kvm_vm_ioctl_create_spapr_tce_iommu(struct kvm *kvm, kvm_get_kvm(kvm); mutex_lock(&kvm->lock); + kvmppc_iommu_hugepages_init(tt); list_add(&tt->list, &kvm->arch.spapr_tce_tables); mutex_unlock(&kvm->lock); @@ -307,10 +344,17 @@ long kvm_vm_ioctl_create_spapr_tce_iommu(struct kvm *kvm, /* Converts guest physical address to host virtual address */ static void __user *kvmppc_vm_gpa_to_hva_and_get(struct kvm_vcpu *vcpu, + struct kvmppc_spapr_tce_table *tt, unsigned long gpa, struct page **pg, unsigned long *hpa) { unsigned long hva, gfn = gpa >> PAGE_SHIFT; struct kvm_memory_slot *memslot; +#ifdef CONFIG_IOMMU_API + struct kvmppc_spapr_iommu_hugepage *hp; + unsigned key = KVMPPC_SPAPR_HUGEPAGE_HASH(gpa); + pte_t *ptep; + unsigned int shift = 0; +#endif memslot = search_memslots(kvm_memslots(vcpu->kvm), gfn); if (!memslot) @@ -325,6 +369,54 @@ static void __user *kvmppc_vm_gpa_to_hva_and_get(struct kvm_vcpu *vcpu, *hpa = __pa((unsigned long) page_address(*pg)) + (hva & ~PAGE_MASK); +#ifdef CONFIG_IOMMU_API + if (!PageCompound(*pg)) + return (void *) hva; + + spin_lock(&tt->hugepages_write_lock); + hash_for_each_possible_rcu(tt->hash_tab, hp, hash_node, key) { + if ((gpa < hp->gpa) || (gpa >= hp->gpa + hp->size)) + continue; + if (hpa) + *hpa = __pa((unsigned long) page_address(hp->page)) + + (hva & (hp->size - 1)); + goto unlock_exit; + } + + ptep = find_linux_pte_or_hugepte(vcpu->arch.pgdir, hva, &shift); + WARN_ON(!ptep); + + if (!ptep || (shift <= PAGE_SHIFT)) { + hva = (unsigned long) ERROR_ADDR; + goto unlock_exit; + } + + hp = kzalloc(sizeof(*hp), GFP_KERNEL); + if (!hp) { + hva = (unsigned long) ERROR_ADDR; + goto unlock_exit; + } + + hp->gpa = gpa & ~((1 << shift) - 1); + hp->hpa = (pte_pfn(*ptep) << PAGE_SHIFT); + hp->size = 1 << shift; + + if (get_user_pages_fast(hva & ~(hp->size - 1), 1, 1, &hp->page) != 1) { + hva = (unsigned long) ERROR_ADDR; + kfree(hp); + goto unlock_exit; + } + hash_add_rcu(tt->hash_tab, &hp->hash_node, key); + + if (hpa) + *hpa = __pa((unsigned long) page_address(hp->page)) + + (hva & (hp->size - 1)); +unlock_exit: + spin_unlock(&tt->hugepages_write_lock); + + put_page(*pg); + *pg = NULL; +#endif /* CONFIG_IOMMU_API */ return (void *) hva; } @@ -363,7 +455,7 @@ long kvmppc_vm_h_put_tce_iommu(struct kvm_vcpu *vcpu, if (iommu_tce_put_param_check(tbl, ioba, tce)) return H_PARAMETER; - hva = kvmppc_vm_gpa_to_hva_and_get(vcpu, tce, &pg, &hpa); + hva = kvmppc_vm_gpa_to_hva_and_get(vcpu, tt, tce, &pg, &hpa); if (hva == ERROR_ADDR) return H_HARDWARE; } @@ -372,7 +464,7 @@ long kvmppc_vm_h_put_tce_iommu(struct kvm_vcpu *vcpu, return H_SUCCESS; pg = pfn_to_page(hpa >> PAGE_SHIFT); - if (pg) + if (pg && !PageCompound(pg)) put_page(pg); return H_HARDWARE; @@ -414,7 +506,7 @@ static long kvmppc_vm_h_put_tce_indirect_iommu(struct kvm_vcpu *vcpu, (i << IOMMU_PAGE_SHIFT), gpa)) return H_PARAMETER; - hva = kvmppc_vm_gpa_to_hva_and_get(vcpu, gpa, &pg, + hva = kvmppc_vm_gpa_to_hva_and_get(vcpu, tt, gpa, &pg, &vcpu->arch.tce_tmp_hpas[i]); if (hva == ERROR_ADDR) goto putpages_flush_exit; @@ -429,7 +521,7 @@ putpages_flush_exit: for ( --i; i >= 0; --i) { struct page *pg; pg = pfn_to_page(vcpu->arch.tce_tmp_hpas[i] >> PAGE_SHIFT); - if (pg) + if (pg && !PageCompound(pg)) put_page(pg); } @@ -517,7 +609,7 @@ long kvmppc_vm_h_put_tce_indirect(struct kvm_vcpu *vcpu, if ((ioba + (npages << IOMMU_PAGE_SHIFT)) > tt->window_size) return H_PARAMETER; - tces = kvmppc_vm_gpa_to_hva_and_get(vcpu, tce_list, &pg, NULL); + tces = kvmppc_vm_gpa_to_hva_and_get(vcpu, tt, tce_list, &pg, NULL); if (tces == ERROR_ADDR) return H_TOO_HARD; @@ -547,7 +639,7 @@ long kvmppc_vm_h_put_tce_indirect(struct kvm_vcpu *vcpu, kvmppc_emulated_put_tce(tt, ioba + (i << IOMMU_PAGE_SHIFT), vcpu->arch.tce_tmp_hpas[i]); put_list_page_exit: - if (pg) + if (pg && !PageCompound(pg)) put_page(pg); if (vcpu->arch.tce_rm_fail != TCERM_NONE) { diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c index f8103c6..8c6449f 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c @@ -132,6 +132,7 @@ EXPORT_SYMBOL_GPL(kvmppc_emulated_put_tce); * returns ERROR_ADDR if failed. */ static unsigned long kvmppc_rm_gpa_to_hpa_and_get(struct kvm_vcpu *vcpu, + struct kvmppc_spapr_tce_table *tt, unsigned long gpa, struct page **pg) { struct kvm_memory_slot *memslot; @@ -139,6 +140,20 @@ static unsigned long kvmppc_rm_gpa_to_hpa_and_get(struct kvm_vcpu *vcpu, unsigned long hva, hpa = ERROR_ADDR; unsigned long gfn = gpa >> PAGE_SHIFT; unsigned shift = 0; + struct kvmppc_spapr_iommu_hugepage *hp; + + /* Try to find an already used hugepage */ + unsigned key = KVMPPC_SPAPR_HUGEPAGE_HASH(gpa); + + hash_for_each_possible_rcu_notrace(tt->hash_tab, hp, + hash_node, key) { + if ((gpa < hp->gpa) || (gpa >= hp->gpa + hp->size)) + continue; + + *pg = NULL; /* Tell the caller not to put page */ + + return hp->hpa + (gpa & (hp->size - 1)); + } memslot = search_memslots(kvm_memslots(vcpu->kvm), gfn); if (!memslot) @@ -208,7 +223,7 @@ static long kvmppc_h_put_tce_iommu(struct kvm_vcpu *vcpu, if (iommu_tce_put_param_check(tbl, ioba, tce)) return H_PARAMETER; - hpa = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tce, &pg); + hpa = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tt, tce, &pg); if (hpa == ERROR_ADDR) return H_TOO_HARD; @@ -247,7 +262,7 @@ static long kvmppc_h_put_tce_indirect_iommu(struct kvm_vcpu *vcpu, /* Translate TCEs and go get_page() */ for (i = 0; i < npages; ++i) { - hpa = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tces[i], &pg); + hpa = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tt, tces[i], &pg); if (hpa == ERROR_ADDR) { vcpu->arch.tce_tmp_num = i; vcpu->arch.tce_rm_fail = TCERM_GETPAGE; @@ -342,7 +357,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, if ((ioba + (npages << IOMMU_PAGE_SHIFT)) > tt->window_size) return H_PARAMETER; - tces = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tce_list, &pg); + tces = kvmppc_rm_gpa_to_hpa_and_get(vcpu, tt, tce_list, &pg); if (tces == ERROR_ADDR) return H_TOO_HARD; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/