From 9a94d3ee2d159927c0f8e5078228eadbce8dda43 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 8 Oct 2018 16:30:57 +1100 Subject: [PATCH] KVM: PPC: Book3S HV: Add a debugfs file to dump radix mappings This adds a file called 'radix' in the debugfs directory for the guest, which when read gives all of the valid leaf PTEs in the partition-scoped radix tree for a radix guest, in human-readable format. It is analogous to the existing 'htab' file which dumps the HPT entries for a HPT guest. Reviewed-by: David Gibson Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/kvm_book3s_64.h | 1 + arch/powerpc/include/asm/kvm_host.h | 1 + arch/powerpc/kvm/book3s_64_mmu_radix.c | 179 +++++++++++++++++++++++ arch/powerpc/kvm/book3s_hv.c | 2 + 4 files changed, 183 insertions(+) diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h index dc435a5af7d6..af25aaa24090 100644 --- a/arch/powerpc/include/asm/kvm_book3s_64.h +++ b/arch/powerpc/include/asm/kvm_book3s_64.h @@ -435,6 +435,7 @@ static inline struct kvm_memslots *kvm_memslots_raw(struct kvm *kvm) } extern void kvmppc_mmu_debugfs_init(struct kvm *kvm); +extern void kvmhv_radix_debugfs_init(struct kvm *kvm); extern void kvmhv_rm_send_ipi(int cpu); diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 3cd0b9f45c2a..a3d4f61a409d 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -291,6 +291,7 @@ struct kvm_arch { u64 process_table; struct dentry *debugfs_dir; struct dentry *htab_dentry; + struct dentry *radix_dentry; struct kvm_resize_hpt *resize_hpt; /* protected by kvm->lock */ #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */ #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index 933c574e1cf7..71951b5a2c68 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -10,6 +10,9 @@ #include #include #include +#include +#include +#include #include #include @@ -853,6 +856,182 @@ static void pmd_ctor(void *addr) memset(addr, 0, RADIX_PMD_TABLE_SIZE); } +struct debugfs_radix_state { + struct kvm *kvm; + struct mutex mutex; + unsigned long gpa; + int chars_left; + int buf_index; + char buf[128]; + u8 hdr; +}; + +static int debugfs_radix_open(struct inode *inode, struct file *file) +{ + struct kvm *kvm = inode->i_private; + struct debugfs_radix_state *p; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + kvm_get_kvm(kvm); + p->kvm = kvm; + mutex_init(&p->mutex); + file->private_data = p; + + return nonseekable_open(inode, file); +} + +static int debugfs_radix_release(struct inode *inode, struct file *file) +{ + struct debugfs_radix_state *p = file->private_data; + + kvm_put_kvm(p->kvm); + kfree(p); + return 0; +} + +static ssize_t debugfs_radix_read(struct file *file, char __user *buf, + size_t len, loff_t *ppos) +{ + struct debugfs_radix_state *p = file->private_data; + ssize_t ret, r; + unsigned long n; + struct kvm *kvm; + unsigned long gpa; + pgd_t *pgt; + pgd_t pgd, *pgdp; + pud_t pud, *pudp; + pmd_t pmd, *pmdp; + pte_t *ptep; + int shift; + unsigned long pte; + + kvm = p->kvm; + if (!kvm_is_radix(kvm)) + return 0; + + ret = mutex_lock_interruptible(&p->mutex); + if (ret) + return ret; + + if (p->chars_left) { + n = p->chars_left; + if (n > len) + n = len; + r = copy_to_user(buf, p->buf + p->buf_index, n); + n -= r; + p->chars_left -= n; + p->buf_index += n; + buf += n; + len -= n; + ret = n; + if (r) { + if (!n) + ret = -EFAULT; + goto out; + } + } + + gpa = p->gpa; + pgt = kvm->arch.pgtable; + while (len != 0 && gpa < RADIX_PGTABLE_RANGE) { + if (!p->hdr) { + n = scnprintf(p->buf, sizeof(p->buf), + "pgdir: %lx\n", (unsigned long)pgt); + p->hdr = 1; + goto copy; + } + + pgdp = pgt + pgd_index(gpa); + pgd = READ_ONCE(*pgdp); + if (!(pgd_val(pgd) & _PAGE_PRESENT)) { + gpa = (gpa & PGDIR_MASK) + PGDIR_SIZE; + continue; + } + + pudp = pud_offset(&pgd, gpa); + pud = READ_ONCE(*pudp); + if (!(pud_val(pud) & _PAGE_PRESENT)) { + gpa = (gpa & PUD_MASK) + PUD_SIZE; + continue; + } + if (pud_val(pud) & _PAGE_PTE) { + pte = pud_val(pud); + shift = PUD_SHIFT; + goto leaf; + } + + pmdp = pmd_offset(&pud, gpa); + pmd = READ_ONCE(*pmdp); + if (!(pmd_val(pmd) & _PAGE_PRESENT)) { + gpa = (gpa & PMD_MASK) + PMD_SIZE; + continue; + } + if (pmd_val(pmd) & _PAGE_PTE) { + pte = pmd_val(pmd); + shift = PMD_SHIFT; + goto leaf; + } + + ptep = pte_offset_kernel(&pmd, gpa); + pte = pte_val(READ_ONCE(*ptep)); + if (!(pte & _PAGE_PRESENT)) { + gpa += PAGE_SIZE; + continue; + } + shift = PAGE_SHIFT; + leaf: + n = scnprintf(p->buf, sizeof(p->buf), + " %lx: %lx %d\n", gpa, pte, shift); + gpa += 1ul << shift; + copy: + p->chars_left = n; + if (n > len) + n = len; + r = copy_to_user(buf, p->buf, n); + n -= r; + p->chars_left -= n; + p->buf_index = n; + buf += n; + len -= n; + ret += n; + if (r) { + if (!ret) + ret = -EFAULT; + break; + } + } + p->gpa = gpa; + + out: + mutex_unlock(&p->mutex); + return ret; +} + +static ssize_t debugfs_radix_write(struct file *file, const char __user *buf, + size_t len, loff_t *ppos) +{ + return -EACCES; +} + +static const struct file_operations debugfs_radix_fops = { + .owner = THIS_MODULE, + .open = debugfs_radix_open, + .release = debugfs_radix_release, + .read = debugfs_radix_read, + .write = debugfs_radix_write, + .llseek = generic_file_llseek, +}; + +void kvmhv_radix_debugfs_init(struct kvm *kvm) +{ + kvm->arch.radix_dentry = debugfs_create_file("radix", 0400, + kvm->arch.debugfs_dir, kvm, + &debugfs_radix_fops); +} + int kvmppc_radix_init(void) { unsigned long size = sizeof(void *) << RADIX_PTE_INDEX_SIZE; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 3334ed9e17e8..deaca0135aba 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4485,6 +4485,8 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm) snprintf(buf, sizeof(buf), "vm%d", current->pid); kvm->arch.debugfs_dir = debugfs_create_dir(buf, kvm_debugfs_dir); kvmppc_mmu_debugfs_init(kvm); + if (radix_enabled()) + kvmhv_radix_debugfs_init(kvm); return 0; } -- GitLab