This patch adds a file named lazy_tscdeadline, in kvm debugfs vcpu
directory to get the state. And also, if you write to it, it will
trigger a lazy_tscdeadline kick forcily which can rescue the guest
if the feature fall into bug.
Signed-off-by: Wang Jianchao <jianchwa@xxxxxxxxxxx>
---
arch/x86/kvm/debugfs.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 79 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c
index ee8c4c3..fbd6552 100644
--- a/arch/x86/kvm/debugfs.c
+++ b/arch/x86/kvm/debugfs.c
@@ -56,6 +56,79 @@ static int vcpu_get_tsc_scaling_frac_bits(void *data, u64 *val)
DEFINE_SIMPLE_ATTRIBUTE(vcpu_tsc_scaling_frac_fops, vcpu_get_tsc_scaling_frac_bits, NULL, "%llu\n");
+static int vcpu_lazy_tscddl_show(struct seq_file *m, void *v)
+{
+ struct kvm_vcpu *vcpu = m->private;
+
+ if (vcpu->arch.pv_cpuid.features & (1UL << KVM_FEATURE_LAZY_TSCDEADLINE)) {
+ struct kvm_host_lazy_tscdeadline *hlt = &vcpu->arch.lazy_tscdeadline;
+ if (!(hlt->msr_val & KVM_MSR_ENABLED) ||
+ !hlt->guest)
+ seq_printf(m, "not open in guest\n");
+ else
+ seq_printf(m, "pending %llu armed %llu\n",
+ hlt->guest->pending, hlt->guest->armed);
+ } else {
+ seq_printf(m, "not enable in cpuid\n");
+ }
+
+ return 0;
+}
+
+static int vcpu_lazy_tscdeadline_open(struct inode *inode, struct file *file)
+{
+ struct kvm_vcpu *vcpu = inode->i_private;
+ struct kvm *kvm = vcpu->kvm;
+ int ret;
+
+ if (!kvm_get_kvm_safe(kvm))
+ return -ENOENT;
+
+ ret = single_open(file, vcpu_lazy_tscddl_show, vcpu);
+ if (ret < 0)
+ kvm_put_kvm(kvm);
+
+ return 0;
+}
+
+static ssize_t vcpu_lazy_tscdeadline_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct seq_file *m = file->private_data;
+ struct kvm_vcpu *vcpu = m->private;
+ struct kvm_host_lazy_tscdeadline *hlt = &vcpu->arch.lazy_tscdeadline;
+
+ if (!(hlt->msr_val & KVM_MSR_ENABLED) ||
+ !hlt->guest)
+ goto out;
+
+ /*
+ * Force to kick the tscdeadline timer to rescue the vcpu
+ */
+ kvm_make_request(KVM_REQ_LAZY_TSCDEADLINE, vcpu);
+ kvm_vcpu_kick(vcpu);
+out:
+ return count;
+}
+
+static int vcpu_lazy_tscdeadline_release(struct inode *inode, struct file *file)
+{
+ struct kvm_vcpu *vcpu = inode->i_private;
+ struct kvm *kvm = vcpu->kvm;
+
+ kvm_put_kvm(kvm);
+
+ return 0;
+}
+
+static const struct file_operations vcpu_lazy_tscdeadline_fops = {
+ .open = vcpu_lazy_tscdeadline_open,
+ .read = seq_read,
+ .write = vcpu_lazy_tscdeadline_write,
+ .llseek = seq_lseek,
+ .release = vcpu_lazy_tscdeadline_release,
+};
+
void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry)
{
debugfs_create_file("guest_mode", 0444, debugfs_dentry, vcpu,
@@ -63,11 +136,16 @@ void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_
debugfs_create_file("tsc-offset", 0444, debugfs_dentry, vcpu,
&vcpu_tsc_offset_fops);
- if (lapic_in_kernel(vcpu))
+ if (lapic_in_kernel(vcpu)) {
debugfs_create_file("lapic_timer_advance_ns", 0444,
debugfs_dentry, vcpu,
&vcpu_timer_advance_ns_fops);
+ debugfs_create_file("lazy_tscdeadline", 0644,
+ debugfs_dentry, vcpu,
+ &vcpu_lazy_tscdeadline_fops);
+ }
+
if (kvm_caps.has_tsc_control) {
debugfs_create_file("tsc-scaling-ratio", 0444,
debugfs_dentry, vcpu,
--
2.7.4
