8 files changed, 467 insertions, 12 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 6671fdc0afb1..a5607c571cb3 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2071,6 +2071,60 @@ KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm
 
 Note that the vcpu ioctl is asynchronous to vcpu execution.
 
+4.78 KVM_PPC_GET_HTAB_FD
+
+Capability: KVM_CAP_PPC_HTAB_FD
+Architectures: powerpc
+Type: vm ioctl
+Parameters: Pointer to struct kvm_get_htab_fd (in)
+Returns: file descriptor number (>= 0) on success, -1 on error
+
+This returns a file descriptor that can be used either to read out the
+entries in the guest's hashed page table (HPT), or to write entries to
+initialize the HPT.  The returned fd can only be written to if the
+KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and
+can only be read if that bit is clear.  The argument struct looks like
+this:
+
+/* For KVM_PPC_GET_HTAB_FD */
+struct kvm_get_htab_fd {
+        __u64   flags;
+        __u64   start_index;
+        __u64   reserved[2];
+};
+
+/* Values for kvm_get_htab_fd.flags */
+#define KVM_GET_HTAB_BOLTED_ONLY        ((__u64)0x1)
+#define KVM_GET_HTAB_WRITE              ((__u64)0x2)
+
+The `start_index' field gives the index in the HPT of the entry at
+which to start reading.  It is ignored when writing.
+
+Reads on the fd will initially supply information about all
+"interesting" HPT entries.  Interesting entries are those with the
+bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise
+all entries.  When the end of the HPT is reached, the read() will
+return.  If read() is called again on the fd, it will start again from
+the beginning of the HPT, but will only return HPT entries that have
+changed since they were last read.
+
+Data read or written is structured as a header (8 bytes) followed by a
+series of valid HPT entries (16 bytes) each.  The header indicates how
+many valid HPT entries there are and how many invalid entries follow
+the valid entries.  The invalid entries are not represented explicitly
+in the stream.  The header format is:
+
+struct kvm_get_htab_header {
+        __u32   index;
+        __u16   n_valid;
+        __u16   n_invalid;
+};
+
+Writes to the fd create HPT entries starting at the index given in the
+header; first `n_valid' valid entries with contents from the data
+written, then `n_invalid' invalid entries, invalidating any previously
+valid entries found.
+
 
 5. The kvm_run structure
 ------------------------
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index b322e5bd6964..38bec1dc9928 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -246,4 +246,26 @@ static inline bool slot_is_aligned(struct kvm_memory_slot *memslot,
         return !(memslot->base_gfn & mask) && !(memslot->npages & mask);
 }
 
+/*
+ * This works for 4k, 64k and 16M pages on POWER7,
+ * and 4k and 16M pages on PPC970.
+ */
+static inline unsigned long slb_pgsize_encoding(unsigned long psize)
+{
+        unsigned long senc = 0;
+
+        if (psize > 0x1000) {
+                senc = SLB_VSID_L;
+                if (psize == 0x10000)
+                        senc |= SLB_VSID_LP_01;
+        }
+        return senc;
+}
+
+static inline int is_vrma_hpte(unsigned long hpte_v)
+{
+        return (hpte_v & ~0xffffffUL) ==
+                (HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)));
+}
+
 #endif /* __ASM_KVM_BOOK3S_64_H__ */
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 609cca3e9426..1ca31e92ee75 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -164,6 +164,8 @@ extern void kvmppc_bookehv_exit(void);
 
 extern int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu);
 
+extern int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *);
+
 /*
  * Cuts out inst bits with ordering according to spec.
  * That means the leftmost bit is zero. All given bits are included.
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index b89ae4db45ce..514883dd311e 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -331,6 +331,31 @@ struct kvm_book3e_206_tlb_params {
         __u32 reserved[8];
 };
 
+/* For KVM_PPC_GET_HTAB_FD */
+struct kvm_get_htab_fd {
+        __u64   flags;
+        __u64   start_index;
+        __u64   reserved[2];
+};
+
+/* Values for kvm_get_htab_fd.flags */
+#define KVM_GET_HTAB_BOLTED_ONLY        ((__u64)0x1)
+#define KVM_GET_HTAB_WRITE              ((__u64)0x2)
+
+/*
+ * Data read on the file descriptor is formatted as a series of
+ * records, each consisting of a header followed by a series of
+ * `n_valid' HPTEs (16 bytes each), which are all valid.  Following
+ * those valid HPTEs there are `n_invalid' invalid HPTEs, which
+ * are not represented explicitly in the stream.  The same format
+ * is used for writing.
+ */
+struct kvm_get_htab_header {
+        __u32   index;
+        __u16   n_valid;
+        __u16   n_invalid;
+};
+
 #define KVM_REG_PPC_HIOR        (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x1)
 #define KVM_REG_PPC_IAC1        (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x2)
 #define KVM_REG_PPC_IAC2        (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x3)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 6ee6516a0bee..0aa40734c8f6 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -25,6 +25,8 @@
 #include <linux/hugetlb.h>
 #include <linux/vmalloc.h>
 #include <linux/srcu.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
 
 #include <asm/tlbflush.h>
 #include <asm/kvm_ppc.h>
@@ -1145,6 +1147,348 @@ void kvmppc_unpin_guest_page(struct kvm *kvm, void *va)
         put_page(page);
 }
 
+/*
+ * Functions for reading and writing the hash table via reads and
+ * writes on a file descriptor.
+ *
+ * Reads return the guest view of the hash table, which has to be
+ * pieced together from the real hash table and the guest_rpte
+ * values in the revmap array.
+ *
+ * On writes, each HPTE written is considered in turn, and if it
+ * is valid, it is written to the HPT as if an H_ENTER with the
+ * exact flag set was done.  When the invalid count is non-zero
+ * in the header written to the stream, the kernel will make
+ * sure that that many HPTEs are invalid, and invalidate them
+ * if not.
+ */
+
+struct kvm_htab_ctx {
+        unsigned long   index;
+        unsigned long   flags;
+        struct kvm      *kvm;
+        int             first_pass;
+};
+
+#define HPTE_SIZE       (2 * sizeof(unsigned long))
+
+static long record_hpte(unsigned long flags, unsigned long *hptp,
+                        unsigned long *hpte, struct revmap_entry *revp,
+                        int want_valid, int first_pass)
+{
+        unsigned long v, r;
+        int ok = 1;
+        int valid, dirty;
+
+        /* Unmodified entries are uninteresting except on the first pass */
+        dirty = !!(revp->guest_rpte & HPTE_GR_MODIFIED);
+        if (!first_pass && !dirty)
+                return 0;
+
+        valid = 0;
+        if (hptp[0] & (HPTE_V_VALID | HPTE_V_ABSENT)) {
+                valid = 1;
+                if ((flags & KVM_GET_HTAB_BOLTED_ONLY) &&
+                    !(hptp[0] & HPTE_V_BOLTED))
+                        valid = 0;
+        }
+        if (valid != want_valid)
+                return 0;
+
+        v = r = 0;
+        if (valid || dirty) {
+                /* lock the HPTE so it's stable and read it */
+                preempt_disable();
+                while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
+                        cpu_relax();
+                v = hptp[0];
+                if (v & HPTE_V_ABSENT) {
+                        v &= ~HPTE_V_ABSENT;
+                        v |= HPTE_V_VALID;
+                }
+                /* re-evaluate valid and dirty from synchronized HPTE value */
+                valid = !!(v & HPTE_V_VALID);
+                if ((flags & KVM_GET_HTAB_BOLTED_ONLY) && !(v & HPTE_V_BOLTED))
+                        valid = 0;
+                r = revp->guest_rpte | (hptp[1] & (HPTE_R_R | HPTE_R_C));
+                dirty = !!(revp->guest_rpte & HPTE_GR_MODIFIED);
+                /* only clear modified if this is the right sort of entry */
+                if (valid == want_valid && dirty) {
+                        r &= ~HPTE_GR_MODIFIED;
+                        revp->guest_rpte = r;
+                }
+                asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
+                hptp[0] &= ~HPTE_V_HVLOCK;
+                preempt_enable();
+                if (!(valid == want_valid && (first_pass || dirty)))
+                        ok = 0;
+        }
+        hpte[0] = v;
+        hpte[1] = r;
+        return ok;
+}
+
+static ssize_t kvm_htab_read(struct file *file, char __user *buf,
+                             size_t count, loff_t *ppos)
+{
+        struct kvm_htab_ctx *ctx = file->private_data;
+        struct kvm *kvm = ctx->kvm;
+        struct kvm_get_htab_header hdr;
+        unsigned long *hptp;
+        struct revmap_entry *revp;
+        unsigned long i, nb, nw;
+        unsigned long __user *lbuf;
+        struct kvm_get_htab_header __user *hptr;
+        unsigned long flags;
+        int first_pass;
+        unsigned long hpte[2];
+
+        if (!access_ok(VERIFY_WRITE, buf, count))
+                return -EFAULT;
+
+        first_pass = ctx->first_pass;
+        flags = ctx->flags;
+
+        i = ctx->index;
+        hptp = (unsigned long *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+        revp = kvm->arch.revmap + i;
+        lbuf = (unsigned long __user *)buf;
+
+        nb = 0;
+        while (nb + sizeof(hdr) + HPTE_SIZE < count) {
+                /* Initialize header */
+                hptr = (struct kvm_get_htab_header __user *)buf;
+                hdr.index = i;
+                hdr.n_valid = 0;
+                hdr.n_invalid = 0;
+                nw = nb;
+                nb += sizeof(hdr);
+                lbuf = (unsigned long __user *)(buf + sizeof(hdr));
+
+                /* Skip uninteresting entries, i.e. clean on not-first pass */
+                if (!first_pass) {
+                        while (i < kvm->arch.hpt_npte &&
+                               !(revp->guest_rpte & HPTE_GR_MODIFIED)) {
+                                ++i;
+                                hptp += 2;
+                                ++revp;
+                        }
+                }
+
+                /* Grab a series of valid entries */
+                while (i < kvm->arch.hpt_npte &&
+                       hdr.n_valid < 0xffff &&
+                       nb + HPTE_SIZE < count &&
+                       record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
+                        /* valid entry, write it out */
+                        ++hdr.n_valid;
+                        if (__put_user(hpte[0], lbuf) ||
+                            __put_user(hpte[1], lbuf + 1))
+                                return -EFAULT;
+                        nb += HPTE_SIZE;
+                        lbuf += 2;
+                        ++i;
+                        hptp += 2;
+                        ++revp;
+                }
+                /* Now skip invalid entries while we can */
+                while (i < kvm->arch.hpt_npte &&
+                       hdr.n_invalid < 0xffff &&
+                       record_hpte(flags, hptp, hpte, revp, 0, first_pass)) {
+                        /* found an invalid entry */
+                        ++hdr.n_invalid;
+                        ++i;
+                        hptp += 2;
+                        ++revp;
+                }
+
+                if (hdr.n_valid || hdr.n_invalid) {
+                        /* write back the header */
+                        if (__copy_to_user(hptr, &hdr, sizeof(hdr)))
+                                return -EFAULT;
+                        nw = nb;
+                        buf = (char __user *)lbuf;
+                } else {
+                        nb = nw;
+                }
+
+                /* Check if we've wrapped around the hash table */
+                if (i >= kvm->arch.hpt_npte) {
+                        i = 0;
+                        ctx->first_pass = 0;
+                        break;
+                }
+        }
+
+        ctx->index = i;
+
+        return nb;
+}
+
+static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
+                              size_t count, loff_t *ppos)
+{
+        struct kvm_htab_ctx *ctx = file->private_data;
+        struct kvm *kvm = ctx->kvm;
+        struct kvm_get_htab_header hdr;
+        unsigned long i, j;
+        unsigned long v, r;
+        unsigned long __user *lbuf;
+        unsigned long *hptp;
+        unsigned long tmp[2];
+        ssize_t nb;
+        long int err, ret;
+        int rma_setup;
+
+        if (!access_ok(VERIFY_READ, buf, count))
+                return -EFAULT;
+
+        /* lock out vcpus from running while we're doing this */
+        mutex_lock(&kvm->lock);
+        rma_setup = kvm->arch.rma_setup_done;
+        if (rma_setup) {
+                kvm->arch.rma_setup_done = 0;   /* temporarily */
+                /* order rma_setup_done vs. vcpus_running */
+                smp_mb();
+                if (atomic_read(&kvm->arch.vcpus_running)) {
+                        kvm->arch.rma_setup_done = 1;
+                        mutex_unlock(&kvm->lock);
+                        return -EBUSY;
+                }
+        }
+
+        err = 0;
+        for (nb = 0; nb + sizeof(hdr) <= count; ) {
+                err = -EFAULT;
+                if (__copy_from_user(&hdr, buf, sizeof(hdr)))
+                        break;
+
+                err = 0;
+                if (nb + hdr.n_valid * HPTE_SIZE > count)
+                        break;
+
+                nb += sizeof(hdr);
+                buf += sizeof(hdr);
+
+                err = -EINVAL;
+                i = hdr.index;
+                if (i >= kvm->arch.hpt_npte ||
+                    i + hdr.n_valid + hdr.n_invalid > kvm->arch.hpt_npte)
+                        break;
+
+                hptp = (unsigned long *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+                lbuf = (unsigned long __user *)buf;
+                for (j = 0; j < hdr.n_valid; ++j) {
+                        err = -EFAULT;
+                        if (__get_user(v, lbuf) || __get_user(r, lbuf + 1))
+                                goto out;
+                        err = -EINVAL;
+                        if (!(v & HPTE_V_VALID))
+                                goto out;
+                        lbuf += 2;
+                        nb += HPTE_SIZE;
+
+                        if (hptp[0] & (HPTE_V_VALID | HPTE_V_ABSENT))
+                                kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
+                        err = -EIO;
+                        ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, i, v, r,
+                                                         tmp);
+                        if (ret != H_SUCCESS) {
+                                pr_err("kvm_htab_write ret %ld i=%ld v=%lx "
+                                       "r=%lx\n", ret, i, v, r);
+                                goto out;
+                        }
+                        if (!rma_setup && is_vrma_hpte(v)) {
+                                unsigned long psize = hpte_page_size(v, r);
+                                unsigned long senc = slb_pgsize_encoding(psize);
+                                unsigned long lpcr;
+
+                                kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
+                                        (VRMA_VSID << SLB_VSID_SHIFT_1T);
+                                lpcr = kvm->arch.lpcr & ~LPCR_VRMASD;
+                                lpcr |= senc << (LPCR_VRMASD_SH - 4);
+                                kvm->arch.lpcr = lpcr;
+                                rma_setup = 1;
+                        }
+                        ++i;
+                        hptp += 2;
+                }
+
+                for (j = 0; j < hdr.n_invalid; ++j) {
+                        if (hptp[0] & (HPTE_V_VALID | HPTE_V_ABSENT))
+                                kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
+                        ++i;
+                        hptp += 2;
+                }
+                err = 0;
+        }
+
+ out:
+        /* Order HPTE updates vs. rma_setup_done */
+        smp_wmb();
+        kvm->arch.rma_setup_done = rma_setup;
+        mutex_unlock(&kvm->lock);
+
+        if (err)
+                return err;
+        return nb;
+}
+
+static int kvm_htab_release(struct inode *inode, struct file *filp)
+{
+        struct kvm_htab_ctx *ctx = filp->private_data;
+
+        filp->private_data = NULL;
+        if (!(ctx->flags & KVM_GET_HTAB_WRITE))
+                atomic_dec(&ctx->kvm->arch.hpte_mod_interest);
+        kvm_put_kvm(ctx->kvm);
+        kfree(ctx);
+        return 0;
+}
+
+static struct file_operations kvm_htab_fops = {
+        .read           = kvm_htab_read,
+        .write          = kvm_htab_write,
+        .llseek         = default_llseek,
+        .release        = kvm_htab_release,
+};
+
+int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *ghf)
+{
+        int ret;
+        struct kvm_htab_ctx *ctx;
+        int rwflag;
+
+        /* reject flags we don't recognize */
+        if (ghf->flags & ~(KVM_GET_HTAB_BOLTED_ONLY | KVM_GET_HTAB_WRITE))
+                return -EINVAL;
+        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+        if (!ctx)
+                return -ENOMEM;
+        kvm_get_kvm(kvm);
+        ctx->kvm = kvm;
+        ctx->index = ghf->start_index;
+        ctx->flags = ghf->flags;
+        ctx->first_pass = 1;
+
+        rwflag = (ghf->flags & KVM_GET_HTAB_WRITE) ? O_WRONLY : O_RDONLY;
+        ret = anon_inode_getfd("kvm-htab", &kvm_htab_fops, ctx, rwflag);
+        if (ret < 0) {
+                kvm_put_kvm(kvm);
+                return ret;
+        }
+
+        if (rwflag == O_RDONLY) {
+                mutex_lock(&kvm->slots_lock);
+                atomic_inc(&kvm->arch.hpte_mod_interest);
+                /* make sure kvmppc_do_h_enter etc. see the increment */
+                synchronize_srcu_expedited(&kvm->srcu);
+                mutex_unlock(&kvm->slots_lock);
+        }
+
+        return ret;
+}
+
 void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
 {
         struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 843eb754a1d5..a4f59dbcd800 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1563,18 +1563,6 @@ out:
         return r;
 }
 
-static unsigned long slb_pgsize_encoding(unsigned long psize)
-{
-        unsigned long senc = 0;
-
-        if (psize > 0x1000) {
-                senc = SLB_VSID_L;
-                if (psize == 0x10000)
-                        senc |= SLB_VSID_LP_01;
-        }
-        return senc;
-}
-
 static void unpin_slot(struct kvm_memory_slot *memslot)
 {
         unsigned long *physp;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index d583ea15e151..70739a089560 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -354,6 +354,12 @@ int kvm_dev_ioctl_check_extension(long ext)
                 r = 1;
 #else
                 r = 0;
+                break;
+#endif
+#ifdef CONFIG_KVM_BOOK3S_64_HV
+        case KVM_CAP_PPC_HTAB_FD:
+                r = 1;
+                break;
 #endif
                 break;
         case KVM_CAP_NR_VCPUS:
@@ -954,6 +960,17 @@ long kvm_arch_vm_ioctl(struct file *filp,
                 r = 0;
                 break;
         }
+
+        case KVM_PPC_GET_HTAB_FD: {
+                struct kvm *kvm = filp->private_data;
+                struct kvm_get_htab_fd ghf;
+
+                r = -EFAULT;
+                if (copy_from_user(&ghf, argp, sizeof(ghf)))
+                        break;
+                r = kvm_vm_ioctl_get_htab_fd(kvm, &ghf);
+                break;
+        }
 #endif /* CONFIG_KVM_BOOK3S_64_HV */
 
 #ifdef CONFIG_PPC_BOOK3S_64
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 494a84c37c3e..e6e5d4b13708 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -634,6 +634,7 @@ struct kvm_ppc_smmu_info {
 #endif
 #define KVM_CAP_IRQFD_RESAMPLE 82
 #define KVM_CAP_PPC_BOOKE_WATCHDOG 83
+#define KVM_CAP_PPC_HTAB_FD 84
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -859,6 +860,8 @@ struct kvm_s390_ucas_mapping {
 #define KVM_CREATE_SPAPR_TCE      _IOW(KVMIO,  0xa8, struct kvm_create_spapr_tce)
 /* Available with KVM_CAP_RMA */
 #define KVM_ALLOCATE_RMA          _IOR(KVMIO,  0xa9, struct kvm_allocate_rma)
+/* Available with KVM_CAP_PPC_HTAB_FD */
+#define KVM_PPC_GET_HTAB_FD       _IOW(KVMIO,  0xaa, struct kvm_get_htab_fd)
 
 /*
  * ioctls for vcpu fds