From fcfe1baeddbf1c7c448b44c82586d0cbc8abc9f5 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Fri, 18 Jun 2021 22:27:05 +0000 Subject: KVM: stats: Support binary stats retrieval for a VM Add a VM ioctl to get a statistics file descriptor by which a read functionality is provided for userspace to read out VM stats header, descriptors and data. Define VM 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: <20210618222709.1858088-4-jingzhangos@google.com> Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cec986487b30..33ec43a87d0f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4055,6 +4055,42 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm, } } +static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer, + size_t size, loff_t *offset) +{ + struct kvm *kvm = file->private_data; + + return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header, + &kvm_vm_stats_desc[0], &kvm->stat, + sizeof(kvm->stat), user_buffer, size, offset); +} + +static const struct file_operations kvm_vm_stats_fops = { + .read = kvm_vm_stats_read, + .llseek = noop_llseek, +}; + +static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) +{ + int fd; + struct file *file; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + file = anon_inode_getfile("kvm-vm-stats", + &kvm_vm_stats_fops, kvm, 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_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -4237,6 +4273,9 @@ static long kvm_vm_ioctl(struct file *filp, case KVM_RESET_DIRTY_RINGS: r = kvm_vm_ioctl_reset_dirty_pages(kvm); break; + case KVM_GET_STATS_FD: + r = kvm_vm_ioctl_get_stats_fd(kvm); + break; default: r = kvm_arch_vm_ioctl(filp, ioctl, arg); } @@ -4316,6 +4355,9 @@ static int kvm_dev_ioctl_create_vm(unsigned long type) if (r < 0) goto put_kvm; + snprintf(kvm->stats_id, sizeof(kvm->stats_id), + "kvm-%d", task_pid_nr(current)); + file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR); if (IS_ERR(file)) { put_unused_fd(r); -- cgit v1.2.3