From ce55c049459cff0034cc1bcfdce3bf343a2d6317 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Fri, 18 Jun 2021 22:27:06 +0000 Subject: KVM: stats: Support binary stats retrieval for a VCPU Add a VCPU ioctl to get a statistics file descriptor by which a read functionality is provided for userspace to read out VCPU stats header, descriptors and data. Define VCPU statistics descriptors and header for all architectures. Reviewed-by: David Matlack Reviewed-by: Ricardo Koller Reviewed-by: Krish Sadhukhan Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba #arm64 Signed-off-by: Jing Zhang Message-Id: <20210618222709.1858088-5-jingzhangos@google.com> Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) (limited to 'virt/kvm') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 33ec43a87d0f..c8d0028df4ac 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3448,6 +3448,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus); BUG_ON(kvm->vcpus[vcpu->vcpu_idx]); + /* Fill the stats id string for the vcpu */ + snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d", + task_pid_nr(current), id); + /* Now it's all set up, let userspace reach it */ kvm_get_kvm(kvm); r = create_vcpu_fd(vcpu); @@ -3497,6 +3501,44 @@ static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset) return 0; } +static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm_vcpu *vcpu = file->private_data; + + return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header, + &kvm_vcpu_stats_desc[0], &vcpu->stat, + sizeof(vcpu->stat), user_buffer, size, offset); +} + +static const struct file_operations kvm_vcpu_stats_fops = { + .read = kvm_vcpu_stats_read, + .llseek = noop_llseek, +}; + +static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu) +{ + int fd; + struct file *file; + char name[15 + ITOA_MAX_LEN + 1]; + + snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id); + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile(name, &kvm_vcpu_stats_fops, vcpu, O_RDONLY); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + file->f_mode |= FMODE_PREAD; + fd_install(fd, file); + + return fd; +} + static long kvm_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -3694,6 +3736,10 @@ out_free1: r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu); break; } + case KVM_GET_STATS_FD: { + r = kvm_vcpu_ioctl_get_stats_fd(vcpu); + break; + } default: r = kvm_arch_vcpu_ioctl(filp, ioctl, arg); } @@ -3952,6 +3998,8 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) #else return 0; #endif + case KVM_CAP_BINARY_STATS_FD: + return 1; default: break; } @@ -5254,7 +5302,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align, SLAB_ACCOUNT, offsetof(struct kvm_vcpu, arch), - sizeof_field(struct kvm_vcpu, arch), + offsetofend(struct kvm_vcpu, stats_id) + - offsetof(struct kvm_vcpu, arch), NULL); if (!kvm_vcpu_cache) { r = -ENOMEM; -- cgit v1.2.3-59-g8ed1b