From 54738c097163c3f01e67ccc85462b78d4d4f495f Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 29 Jun 2011 00:22:41 +0000 Subject: [PATCH] KVM: PPC: Accelerate H_PUT_TCE by implementing it in real mode This improves I/O performance for guests using the PAPR paravirtualization interface by making the H_PUT_TCE hcall faster, by implementing it in real mode. H_PUT_TCE is used for updating virtual IOMMU tables, and is used both for virtual I/O and for real I/O in the PAPR interface. Since this moves the IOMMU tables into the kernel, we define a new KVM_CREATE_SPAPR_TCE ioctl to allow qemu to create the tables. The ioctl returns a file descriptor which can be used to mmap the newly created table. The qemu driver models use them in the same way as userspace managed tables, but they can be updated directly by the guest with a real-mode H_PUT_TCE implementation, reducing the number of host/guest context switches during guest IO. There are certain circumstances where it is useful for userland qemu to write to the TCE table even if the kernel H_PUT_TCE path is used most of the time. Specifically, allowing this will avoid awkwardness when we need to reset the table. More importantly, we will in the future need to write the table in order to restore its state after a checkpoint resume or migration. Signed-off-by: David Gibson Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- Documentation/virtual/kvm/api.txt | 35 +++++++ arch/powerpc/include/asm/kvm.h | 9 ++ arch/powerpc/include/asm/kvm_book3s_64.h | 2 + arch/powerpc/include/asm/kvm_host.h | 9 ++ arch/powerpc/include/asm/kvm_ppc.h | 2 + arch/powerpc/kvm/Makefile | 3 +- arch/powerpc/kvm/book3s_64_vio_hv.c | 73 ++++++++++++++ arch/powerpc/kvm/book3s_hv.c | 116 ++++++++++++++++++++++- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 +- arch/powerpc/kvm/powerpc.c | 18 ++++ include/linux/kvm.h | 2 + 11 files changed, 268 insertions(+), 3 deletions(-) create mode 100644 arch/powerpc/kvm/book3s_64_vio_hv.c diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index e8875fef3eb8..a1d344d5ff4c 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1350,6 +1350,41 @@ The following flags are defined: If datamatch flag is set, the event will be signaled only if the written value to the registered address is equal to datamatch in struct kvm_ioeventfd. +4.62 KVM_CREATE_SPAPR_TCE + +Capability: KVM_CAP_SPAPR_TCE +Architectures: powerpc +Type: vm ioctl +Parameters: struct kvm_create_spapr_tce (in) +Returns: file descriptor for manipulating the created TCE table + +This creates a virtual TCE (translation control entry) table, which +is an IOMMU for PAPR-style virtual I/O. It is used to translate +logical addresses used in virtual I/O into guest physical addresses, +and provides a scatter/gather capability for PAPR virtual I/O. + +/* for KVM_CAP_SPAPR_TCE */ +struct kvm_create_spapr_tce { + __u64 liobn; + __u32 window_size; +}; + +The liobn field gives the logical IO bus number for which to create a +TCE table. The window_size field specifies the size of the DMA window +which this TCE table will translate - the table will contain one 64 +bit TCE entry for every 4kiB of the DMA window. + +When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE +table has been created using this ioctl(), the kernel will handle it +in real mode, updating the TCE table. H_PUT_TCE calls for other +liobns will cause a vm exit and must be handled by userspace. + +The return value is a file descriptor which can be passed to mmap(2) +to map the created TCE table into userspace. This lets userspace read +the entries written by kernel-handled H_PUT_TCE calls, and also lets +userspace update the TCE table directly which is useful in some +circumstances. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h index d2ca5ed3877b..c3ec990daf45 100644 --- a/arch/powerpc/include/asm/kvm.h +++ b/arch/powerpc/include/asm/kvm.h @@ -22,6 +22,9 @@ #include +/* Select powerpc specific features in */ +#define __KVM_HAVE_SPAPR_TCE + struct kvm_regs { __u64 pc; __u64 cr; @@ -272,4 +275,10 @@ struct kvm_guest_debug_arch { #define KVM_INTERRUPT_UNSET -2U #define KVM_INTERRUPT_SET_LEVEL -3U +/* for KVM_CAP_SPAPR_TCE */ +struct kvm_create_spapr_tce { + __u64 liobn; + __u32 window_size; +}; + #endif /* __LINUX_KVM_POWERPC_H */ diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h index 5f73388ea0af..e43fe42b9875 100644 --- a/arch/powerpc/include/asm/kvm_book3s_64.h +++ b/arch/powerpc/include/asm/kvm_book3s_64.h @@ -27,4 +27,6 @@ static inline struct kvmppc_book3s_shadow_vcpu *to_svcpu(struct kvm_vcpu *vcpu) } #endif +#define SPAPR_TCE_SHIFT 12 + #endif /* __ASM_KVM_BOOK3S_64_H__ */ diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 6ebf1721680a..5616e39a7fa4 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -144,6 +144,14 @@ struct kvmppc_pginfo { atomic_t refcnt; }; +struct kvmppc_spapr_tce_table { + struct list_head list; + struct kvm *kvm; + u64 liobn; + u32 window_size; + struct page *pages[0]; +}; + struct kvm_arch { #ifdef CONFIG_KVM_BOOK3S_64_HV unsigned long hpt_virt; @@ -157,6 +165,7 @@ struct kvm_arch { unsigned long sdr1; unsigned long host_sdr1; int tlbie_lock; + struct list_head spapr_tce_tables; unsigned short last_vcpu[NR_CPUS]; #endif /* CONFIG_KVM_BOOK3S_64_HV */ }; diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 2afe92e6f625..99f6fcf4cf88 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -119,6 +119,8 @@ extern long kvmppc_prepare_vrma(struct kvm *kvm, extern void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem); extern int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu); +extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, + struct kvm_create_spapr_tce *args); extern int kvmppc_core_init_vm(struct kvm *kvm); extern void kvmppc_core_destroy_vm(struct kvm *kvm); extern int kvmppc_core_prepare_memory_region(struct kvm *kvm, diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile index 2ecffc0dc1bb..1de3d54901d4 100644 --- a/arch/powerpc/kvm/Makefile +++ b/arch/powerpc/kvm/Makefile @@ -55,7 +55,8 @@ kvm-book3s_64-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \ book3s_hv_interrupts.o \ book3s_64_mmu_hv.o kvm-book3s_64-builtin-objs-$(CONFIG_KVM_BOOK3S_64_HV) := \ - book3s_hv_rm_mmu.o + book3s_hv_rm_mmu.o \ + book3s_64_vio_hv.o kvm-book3s_64-module-objs := \ ../../../virt/kvm/kvm_main.o \ diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c new file mode 100644 index 000000000000..ea0f8c537c28 --- /dev/null +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c @@ -0,0 +1,73 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * Copyright 2010 Paul Mackerras, IBM Corp. + * Copyright 2011 David Gibson, IBM Corporation + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64)) + +long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, + unsigned long ioba, unsigned long tce) +{ + struct kvm *kvm = vcpu->kvm; + struct kvmppc_spapr_tce_table *stt; + + /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */ + /* liobn, ioba, tce); */ + + list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) { + if (stt->liobn == liobn) { + unsigned long idx = ioba >> SPAPR_TCE_SHIFT; + struct page *page; + u64 *tbl; + + /* udbg_printf("H_PUT_TCE: liobn 0x%lx => stt=%p window_size=0x%x\n", */ + /* liobn, stt, stt->window_size); */ + if (ioba >= stt->window_size) + return H_PARAMETER; + + page = stt->pages[idx / TCES_PER_PAGE]; + tbl = (u64 *)page_address(page); + + /* FIXME: Need to validate the TCE itself */ + /* udbg_printf("tce @ %p\n", &tbl[idx % TCES_PER_PAGE]); */ + tbl[idx % TCES_PER_PAGE] = tce; + return H_SUCCESS; + } + } + + /* Didn't find the liobn, punt it to userspace */ + return H_TOO_HARD; +} diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index af862c30b70e..6fe469eabce8 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -538,6 +538,116 @@ int kvmppc_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu) return r; } +static long kvmppc_stt_npages(unsigned long window_size) +{ + return ALIGN((window_size >> SPAPR_TCE_SHIFT) + * sizeof(u64), PAGE_SIZE) / PAGE_SIZE; +} + +static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt) +{ + struct kvm *kvm = stt->kvm; + int i; + + mutex_lock(&kvm->lock); + list_del(&stt->list); + for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++) + __free_page(stt->pages[i]); + kfree(stt); + mutex_unlock(&kvm->lock); + + kvm_put_kvm(kvm); +} + +static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct kvmppc_spapr_tce_table *stt = vma->vm_file->private_data; + struct page *page; + + if (vmf->pgoff >= kvmppc_stt_npages(stt->window_size)) + return VM_FAULT_SIGBUS; + + page = stt->pages[vmf->pgoff]; + get_page(page); + vmf->page = page; + return 0; +} + +static const struct vm_operations_struct kvm_spapr_tce_vm_ops = { + .fault = kvm_spapr_tce_fault, +}; + +static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma) +{ + vma->vm_ops = &kvm_spapr_tce_vm_ops; + return 0; +} + +static int kvm_spapr_tce_release(struct inode *inode, struct file *filp) +{ + struct kvmppc_spapr_tce_table *stt = filp->private_data; + + release_spapr_tce_table(stt); + return 0; +} + +static struct file_operations kvm_spapr_tce_fops = { + .mmap = kvm_spapr_tce_mmap, + .release = kvm_spapr_tce_release, +}; + +long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, + struct kvm_create_spapr_tce *args) +{ + struct kvmppc_spapr_tce_table *stt = NULL; + long npages; + int ret = -ENOMEM; + int i; + + /* Check this LIOBN hasn't been previously allocated */ + list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) { + if (stt->liobn == args->liobn) + return -EBUSY; + } + + npages = kvmppc_stt_npages(args->window_size); + + stt = kzalloc(sizeof(*stt) + npages* sizeof(struct page *), + GFP_KERNEL); + if (!stt) + goto fail; + + stt->liobn = args->liobn; + stt->window_size = args->window_size; + stt->kvm = kvm; + + for (i = 0; i < npages; i++) { + stt->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!stt->pages[i]) + goto fail; + } + + kvm_get_kvm(kvm); + + mutex_lock(&kvm->lock); + list_add(&stt->list, &kvm->arch.spapr_tce_tables); + + mutex_unlock(&kvm->lock); + + return anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops, + stt, O_RDWR); + +fail: + if (stt) { + for (i = 0; i < npages; i++) + if (stt->pages[i]) + __free_page(stt->pages[i]); + + kfree(stt); + } + return ret; +} + int kvmppc_core_prepare_memory_region(struct kvm *kvm, struct kvm_userspace_memory_region *mem) { @@ -559,13 +669,17 @@ int kvmppc_core_init_vm(struct kvm *kvm) /* Allocate hashed page table */ r = kvmppc_alloc_hpt(kvm); + if (r) + return r; - return r; + INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables); + return 0; } void kvmppc_core_destroy_vm(struct kvm *kvm) { kvmppc_free_hpt(kvm); + WARN_ON(!list_empty(&kvm->arch.spapr_tce_tables)); } /* These are stubs for now */ diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 319ff63b1f31..e6adaadcdff2 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -754,7 +754,7 @@ hcall_real_table: .long 0 /* 0x14 - H_CLEAR_REF */ .long .kvmppc_h_protect - hcall_real_table .long 0 /* 0x1c - H_GET_TCE */ - .long 0 /* 0x20 - H_SET_TCE */ + .long .kvmppc_h_put_tce - hcall_real_table .long 0 /* 0x24 - H_SET_SPRG0 */ .long .kvmppc_h_set_dabr - hcall_real_table .long 0 /* 0x2c */ diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 6fc9ee499b61..c78ceb9d5605 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -202,6 +202,11 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_COALESCED_MMIO: r = KVM_COALESCED_MMIO_PAGE_OFFSET; break; +#endif +#ifdef CONFIG_KVM_BOOK3S_64_HV + case KVM_CAP_SPAPR_TCE: + r = 1; + break; #endif default: r = 0; @@ -653,6 +658,19 @@ long kvm_arch_vm_ioctl(struct file *filp, break; } +#ifdef CONFIG_KVM_BOOK3S_64_HV + case KVM_CREATE_SPAPR_TCE: { + struct kvm_create_spapr_tce create_tce; + struct kvm *kvm = filp->private_data; + + r = -EFAULT; + if (copy_from_user(&create_tce, argp, sizeof(create_tce))) + goto out; + r = kvm_vm_ioctl_create_spapr_tce(kvm, &create_tce); + goto out; + } +#endif /* CONFIG_KVM_BOOK3S_64_HV */ + default: r = -ENOTTY; } diff --git a/include/linux/kvm.h b/include/linux/kvm.h index a156294fc22a..61f56502732e 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -550,6 +550,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_TSC_CONTROL 60 #define KVM_CAP_GET_TSC_KHZ 61 #define KVM_CAP_PPC_BOOKE_SREGS 62 +#define KVM_CAP_SPAPR_TCE 63 #ifdef KVM_CAP_IRQ_ROUTING @@ -752,6 +753,7 @@ struct kvm_clock_data { /* Available with KVM_CAP_XCRS */ #define KVM_GET_XCRS _IOR(KVMIO, 0xa6, struct kvm_xcrs) #define KVM_SET_XCRS _IOW(KVMIO, 0xa7, struct kvm_xcrs) +#define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce) #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) -- 2.20.1