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Commit 9a94d3ee authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
Browse files

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: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 32eb150a

arch/powerpc/include/asm/kvm_book3s_64.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kvm/book3s_64_mmu_radix.c

+179 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kvm/book3s_hv.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

}