On Fri, Sep 21, 2018 at 08:01:41PM +1000, Paul Mackerras wrote:
> 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.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> 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 e0e92f2..e699787 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -4475,6 +4475,8 @@ 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;
> }
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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