[PATCH v4 11/32] KVM: PPC: Book3S HV: Add a debugfs file to dump radix mappings
Paul Mackerras
paulus at ozlabs.org
Thu Oct 4 21:55:48 AEST 2018
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 <david at gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
---
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 dc435a5..af25aaa 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 3cd0b9f..a3d4f61 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 933c574..71951b5 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -10,6 +10,9 @@
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/debugfs.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
@@ -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 3aabbb2..aa13728 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4477,6 +4477,8 @@ 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;
}
--
2.7.4
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