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authorPaul Mackerras <paulus@samba.org>2015-03-28 14:21:01 +1100
committerAlexander Graf <agraf@suse.de>2015-04-21 15:21:31 +0200
commite23a808b1681d398a983ebc51179efc51c4a1eaf (patch)
tree4dd8a7c2a9c5633c767a03ad8999bde471a55eda
parent6e0365b782739eb41b03bcfd23abeefacbf0817a (diff)
downloadkernel-e23a808b1681d398a983ebc51179efc51c4a1eaf.tar.gz
KVM: PPC: Book3S HV: Create debugfs file for each guest's HPT
This creates a debugfs directory for each HV guest (assuming debugfs is enabled in the kernel config), and within that directory, a file by which the contents of the guest's HPT (hashed page table) can be read. The directory is named vmnnnn, where nnnn is the PID of the process that created the guest. The file is named "htab". This is intended to help in debugging problems in the host's management of guest memory. The contents of the file consist of a series of lines like this: 3f48 4000d032bf003505 0000000bd7ff1196 00000003b5c71196 The first field is the index of the entry in the HPT, the second and third are the HPT entry, so the third entry contains the real page number that is mapped by the entry if the entry's valid bit is set. The fourth field is the guest's view of the second doubleword of the entry, so it contains the guest physical address. (The format of the second through fourth fields are described in the Power ISA and also in arch/powerpc/include/asm/mmu-hash64.h.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
-rw-r--r--arch/powerpc/include/asm/kvm_book3s_64.h2
-rw-r--r--arch/powerpc/include/asm/kvm_host.h2
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_hv.c136
-rw-r--r--arch/powerpc/kvm/book3s_hv.c12
-rw-r--r--virt/kvm/kvm_main.c1
5 files changed, 153 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 0789a0f50969..869c53fe02cd 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -436,6 +436,8 @@ static inline struct kvm_memslots *kvm_memslots_raw(struct kvm *kvm)
return rcu_dereference_raw_notrace(kvm->memslots);
}
+extern void kvmppc_mmu_debugfs_init(struct kvm *kvm);
+
#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
#endif /* __ASM_KVM_BOOK3S_64_H__ */
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 015773f5bb33..f1d0bbc0f079 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -238,6 +238,8 @@ struct kvm_arch {
atomic_t hpte_mod_interest;
cpumask_t need_tlb_flush;
int hpt_cma_alloc;
+ struct dentry *debugfs_dir;
+ struct dentry *htab_dentry;
#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
struct mutex hpt_mutex;
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 6c6825a7ae49..d6fe30835c58 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -27,6 +27,7 @@
#include <linux/srcu.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
+#include <linux/debugfs.h>
#include <asm/tlbflush.h>
#include <asm/kvm_ppc.h>
@@ -1490,6 +1491,141 @@ int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *ghf)
return ret;
}
+struct debugfs_htab_state {
+ struct kvm *kvm;
+ struct mutex mutex;
+ unsigned long hpt_index;
+ int chars_left;
+ int buf_index;
+ char buf[64];
+};
+
+static int debugfs_htab_open(struct inode *inode, struct file *file)
+{
+ struct kvm *kvm = inode->i_private;
+ struct debugfs_htab_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_htab_release(struct inode *inode, struct file *file)
+{
+ struct debugfs_htab_state *p = file->private_data;
+
+ kvm_put_kvm(p->kvm);
+ kfree(p);
+ return 0;
+}
+
+static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ struct debugfs_htab_state *p = file->private_data;
+ ssize_t ret, r;
+ unsigned long i, n;
+ unsigned long v, hr, gr;
+ struct kvm *kvm;
+ __be64 *hptp;
+
+ 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;
+ }
+ }
+
+ kvm = p->kvm;
+ i = p->hpt_index;
+ hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+ for (; len != 0 && i < kvm->arch.hpt_npte; ++i, hptp += 2) {
+ if (!(be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)))
+ continue;
+
+ /* lock the HPTE so it's stable and read it */
+ preempt_disable();
+ while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
+ cpu_relax();
+ v = be64_to_cpu(hptp[0]) & ~HPTE_V_HVLOCK;
+ hr = be64_to_cpu(hptp[1]);
+ gr = kvm->arch.revmap[i].guest_rpte;
+ unlock_hpte(hptp, v);
+ preempt_enable();
+
+ if (!(v & (HPTE_V_VALID | HPTE_V_ABSENT)))
+ continue;
+
+ n = scnprintf(p->buf, sizeof(p->buf),
+ "%6lx %.16lx %.16lx %.16lx\n",
+ i, v, hr, gr);
+ 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;
+ goto out;
+ }
+ }
+ p->hpt_index = i;
+
+ out:
+ mutex_unlock(&p->mutex);
+ return ret;
+}
+
+ssize_t debugfs_htab_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ return -EACCES;
+}
+
+static const struct file_operations debugfs_htab_fops = {
+ .owner = THIS_MODULE,
+ .open = debugfs_htab_open,
+ .release = debugfs_htab_release,
+ .read = debugfs_htab_read,
+ .write = debugfs_htab_write,
+ .llseek = generic_file_llseek,
+};
+
+void kvmppc_mmu_debugfs_init(struct kvm *kvm)
+{
+ kvm->arch.htab_dentry = debugfs_create_file("htab", 0400,
+ kvm->arch.debugfs_dir, kvm,
+ &debugfs_htab_fops);
+}
+
void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
{
struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index dde14fd64d8e..08f8617f4046 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -32,6 +32,7 @@
#include <linux/page-flags.h>
#include <linux/srcu.h>
#include <linux/miscdevice.h>
+#include <linux/debugfs.h>
#include <asm/reg.h>
#include <asm/cputable.h>
@@ -2319,6 +2320,7 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
static int kvmppc_core_init_vm_hv(struct kvm *kvm)
{
unsigned long lpcr, lpid;
+ char buf[32];
/* Allocate the guest's logical partition ID */
@@ -2359,6 +2361,14 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
*/
kvm_hv_vm_activated();
+ /*
+ * Create a debugfs directory for the VM
+ */
+ snprintf(buf, sizeof(buf), "vm%d", current->pid);
+ kvm->arch.debugfs_dir = debugfs_create_dir(buf, kvm_debugfs_dir);
+ if (!IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
+ kvmppc_mmu_debugfs_init(kvm);
+
return 0;
}
@@ -2379,6 +2389,8 @@ static void kvmppc_free_vcores(struct kvm *kvm)
static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
{
+ debugfs_remove_recursive(kvm->arch.debugfs_dir);
+
kvm_hv_vm_deactivated();
kvmppc_free_vcores(kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d3fc9399062a..90977418aeb6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -89,6 +89,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
static __read_mostly struct preempt_ops kvm_preempt_ops;
struct dentry *kvm_debugfs_dir;
+EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);