Make the start level and the IPA bits properties available in the
virtual machine debugfs directory. Make sure that the KVM structure
doesn't disappear behind our back and keep a reference to the KVM struct
while these files are opened.
Signed-off-by: Sebastian Ene <sebastianene@google.com>
---
arch/arm64/kvm/ptdump.c | 50 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index cc1d4fdddc6e..17649e3cbc8f 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c
@@ -215,8 +215,58 @@ static const struct file_operations kvm_ptdump_guest_fops = {
.release = kvm_ptdump_guest_close,
};
+static int kvm_pgtable_debugfs_show(struct seq_file *m, void *unused)
+{
+ const struct file *file = m->file;
+ struct kvm_pgtable *pgtable = m->private;
+
+ if (!strcmp(file_dentry(file)->d_iname, "ipa_range"))
+ seq_printf(m, "%2u\n", pgtable->ia_bits);
+ else if (!strcmp(file_dentry(file)->d_iname, "stage2_levels"))
+ seq_printf(m, "%1d\n", pgtable->start_level);
+ return 0;
+}
+
+static int kvm_pgtable_debugfs_open(struct inode *m, struct file *file)
+{
+ struct kvm *kvm = m->i_private;
+ struct kvm_s2_mmu *mmu;
+ struct kvm_pgtable *pgtable;
+ int ret;
+
+ if (!kvm_get_kvm_safe(kvm))
+ return -ENOENT;
+
+ mmu = &kvm->arch.mmu;
+ pgtable = mmu->pgt;
+
+ ret = single_open(file, kvm_pgtable_debugfs_show, pgtable);
+ if (ret < 0)
+ kvm_put_kvm(kvm);
+ return ret;
+}
+
+static int kvm_pgtable_debugfs_close(struct inode *m, struct file *file)
+{
+ struct kvm *kvm = m->i_private;
+
+ kvm_put_kvm(kvm);
+ return single_release(m, file);
+}
+
+static const struct file_operations kvm_pgtable_debugfs_fops = {
+ .open = kvm_pgtable_debugfs_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = kvm_pgtable_debugfs_close,
+};
+
void kvm_ptdump_guest_register(struct kvm *kvm)
{
debugfs_create_file("stage2_page_tables", 0400, kvm->debugfs_dentry,
kvm, &kvm_ptdump_guest_fops);
+ debugfs_create_file("ipa_range", 0400, kvm->debugfs_dentry, kvm,
+ &kvm_pgtable_debugfs_fops);
+ debugfs_create_file("stage2_levels", 0400, kvm->debugfs_dentry,
+ kvm, &kvm_pgtable_debugfs_fops);
}
--
2.45.2.741.gdbec12cfda-googOn Fri, Jun 21, 2024 at 12:32:30PM +0000, Sebastian Ene wrote:
> Make the start level and the IPA bits properties available in the
> virtual machine debugfs directory. Make sure that the KVM structure
> doesn't disappear behind our back and keep a reference to the KVM struct
> while these files are opened.
>
> Signed-off-by: Sebastian Ene <sebastianene@google.com>
> ---
> arch/arm64/kvm/ptdump.c | 50 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
> index cc1d4fdddc6e..17649e3cbc8f 100644
> --- a/arch/arm64/kvm/ptdump.c
> +++ b/arch/arm64/kvm/ptdump.c
> @@ -215,8 +215,58 @@ static const struct file_operations kvm_ptdump_guest_fops = {
> .release = kvm_ptdump_guest_close,
> };
>
> +static int kvm_pgtable_debugfs_show(struct seq_file *m, void *unused)
> +{
> + const struct file *file = m->file;
> + struct kvm_pgtable *pgtable = m->private;
> +
> + if (!strcmp(file_dentry(file)->d_iname, "ipa_range"))
> + seq_printf(m, "%2u\n", pgtable->ia_bits);
> + else if (!strcmp(file_dentry(file)->d_iname, "stage2_levels"))
> + seq_printf(m, "%1d\n", pgtable->start_level);
The name of the file suggests sounds like this is the number of page
table levels instead of the starting level of the walk.
So instead:
seq_printf(m, "%1d\n",
KVM_PGTABLE_LAST_LEVEL - pgtable->start_level + 1);
> + return 0;
> +}
> +
> +static int kvm_pgtable_debugfs_open(struct inode *m, struct file *file)
> +{
> + struct kvm *kvm = m->i_private;
> + struct kvm_s2_mmu *mmu;
> + struct kvm_pgtable *pgtable;
> + int ret;
> +
> + if (!kvm_get_kvm_safe(kvm))
> + return -ENOENT;
> +
> + mmu = &kvm->arch.mmu;
> + pgtable = mmu->pgt;
nitpick: pgtable = &kvm->arch.mmu.pgt
--
Thanks,
Oliver
On Fri, Jun 28, 2024 at 08:49:19PM +0000, Oliver Upton wrote:
> On Fri, Jun 21, 2024 at 12:32:30PM +0000, Sebastian Ene wrote:
> > Make the start level and the IPA bits properties available in the
> > virtual machine debugfs directory. Make sure that the KVM structure
> > doesn't disappear behind our back and keep a reference to the KVM struct
> > while these files are opened.
> >
> > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > ---
> > arch/arm64/kvm/ptdump.c | 50 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 50 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
> > index cc1d4fdddc6e..17649e3cbc8f 100644
> > --- a/arch/arm64/kvm/ptdump.c
> > +++ b/arch/arm64/kvm/ptdump.c
> > @@ -215,8 +215,58 @@ static const struct file_operations kvm_ptdump_guest_fops = {
> > .release = kvm_ptdump_guest_close,
> > };
> >
> > +static int kvm_pgtable_debugfs_show(struct seq_file *m, void *unused)
> > +{
> > + const struct file *file = m->file;
> > + struct kvm_pgtable *pgtable = m->private;
> > +
> > + if (!strcmp(file_dentry(file)->d_iname, "ipa_range"))
> > + seq_printf(m, "%2u\n", pgtable->ia_bits);
> > + else if (!strcmp(file_dentry(file)->d_iname, "stage2_levels"))
> > + seq_printf(m, "%1d\n", pgtable->start_level);
>
> The name of the file suggests sounds like this is the number of page
> table levels instead of the starting level of the walk.
>
> So instead:
>
> seq_printf(m, "%1d\n",
> KVM_PGTABLE_LAST_LEVEL - pgtable->start_level + 1);
>
Ack, I will rewrite this.
> > + return 0;
> > +}
> > +
> > +static int kvm_pgtable_debugfs_open(struct inode *m, struct file *file)
> > +{
> > + struct kvm *kvm = m->i_private;
> > + struct kvm_s2_mmu *mmu;
> > + struct kvm_pgtable *pgtable;
> > + int ret;
> > +
> > + if (!kvm_get_kvm_safe(kvm))
> > + return -ENOENT;
> > +
> > + mmu = &kvm->arch.mmu;
> > + pgtable = mmu->pgt;
>
> nitpick: pgtable = &kvm->arch.mmu.pgt
>
Will fix this.
Thanks,
Seb
> --
> Thanks,
> Oliver
>
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