From 7d189f617f83f780915b737896a696ff605bd19f Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Mon, 15 Mar 2021 17:34:48 +0100 Subject: [PATCH] vdpa_sim_blk: implement ramdisk behaviour The previous implementation wrote only the status of each request. This patch implements a more accurate block device simulator, providing a ramdisk-like behavior and adding input validation. Acked-by: Jason Wang Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefano Garzarella Link: https://lore.kernel.org/r/20210315163450.254396-13-sgarzare@redhat.com Signed-off-by: Michael S. Tsirkin --- drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 164 +++++++++++++++++++++++++++++++---- 1 file changed, 146 insertions(+), 18 deletions(-) diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c index 64926a7..a31964e 100644 --- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c @@ -3,6 +3,7 @@ * VDPA simulator for block device. * * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. + * Copyright (c) 2021, Red Hat Inc. All rights reserved. * */ @@ -14,6 +15,7 @@ #include #include #include +#include #include #include "vdpa_sim.h" @@ -37,10 +39,151 @@ static struct vdpasim *vdpasim_blk_dev; +static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size) +{ + u64 range_sectors = range_size >> SECTOR_SHIFT; + + if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX) + return false; + + if (start_sector > VDPASIM_BLK_CAPACITY) + return false; + + if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector) + return false; + + return true; +} + +/* Returns 'true' if the request is handled (with or without an I/O error) + * and the status is correctly written in the last byte of the 'in iov', + * 'false' otherwise. + */ +static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim, + struct vdpasim_virtqueue *vq) +{ + size_t pushed = 0, to_pull, to_push; + struct virtio_blk_outhdr hdr; + ssize_t bytes; + loff_t offset; + u64 sector; + u8 status; + u32 type; + int ret; + + ret = vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, &vq->in_iov, + &vq->head, GFP_ATOMIC); + if (ret != 1) + return false; + + if (vq->out_iov.used < 1 || vq->in_iov.used < 1) { + dev_err(&vdpasim->vdpa.dev, "missing headers - out_iov: %u in_iov %u\n", + vq->out_iov.used, vq->in_iov.used); + return false; + } + + if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) { + dev_err(&vdpasim->vdpa.dev, "request in header too short\n"); + return false; + } + + /* The last byte is the status and we checked if the last iov has + * enough room for it. + */ + to_push = vringh_kiov_length(&vq->in_iov) - 1; + + to_pull = vringh_kiov_length(&vq->out_iov); + + bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &hdr, + sizeof(hdr)); + if (bytes != sizeof(hdr)) { + dev_err(&vdpasim->vdpa.dev, "request out header too short\n"); + return false; + } + + to_pull -= bytes; + + type = vdpasim32_to_cpu(vdpasim, hdr.type); + sector = vdpasim64_to_cpu(vdpasim, hdr.sector); + offset = sector << SECTOR_SHIFT; + status = VIRTIO_BLK_S_OK; + + switch (type) { + case VIRTIO_BLK_T_IN: + if (!vdpasim_blk_check_range(sector, to_push)) { + dev_err(&vdpasim->vdpa.dev, + "reading over the capacity - offset: 0x%llx len: 0x%zx\n", + offset, to_push); + status = VIRTIO_BLK_S_IOERR; + break; + } + + bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, + vdpasim->buffer + offset, + to_push); + if (bytes < 0) { + dev_err(&vdpasim->vdpa.dev, + "vringh_iov_push_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n", + bytes, offset, to_push); + status = VIRTIO_BLK_S_IOERR; + break; + } + + pushed += bytes; + break; + + case VIRTIO_BLK_T_OUT: + if (!vdpasim_blk_check_range(sector, to_pull)) { + dev_err(&vdpasim->vdpa.dev, + "writing over the capacity - offset: 0x%llx len: 0x%zx\n", + offset, to_pull); + status = VIRTIO_BLK_S_IOERR; + break; + } + + bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, + vdpasim->buffer + offset, + to_pull); + if (bytes < 0) { + dev_err(&vdpasim->vdpa.dev, + "vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n", + bytes, offset, to_pull); + status = VIRTIO_BLK_S_IOERR; + break; + } + break; + + default: + dev_warn(&vdpasim->vdpa.dev, + "Unsupported request type %d\n", type); + status = VIRTIO_BLK_S_IOERR; + break; + } + + /* If some operations fail, we need to skip the remaining bytes + * to put the status in the last byte + */ + if (to_push - pushed > 0) + vringh_kiov_advance(&vq->in_iov, to_push - pushed); + + /* Last byte is the status */ + bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, &status, 1); + if (bytes != 1) + return false; + + pushed += bytes; + + /* Make sure data is wrote before advancing index */ + smp_wmb(); + + vringh_complete_iotlb(&vq->vring, vq->head, pushed); + + return true; +} + static void vdpasim_blk_work(struct work_struct *work) { struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); - u8 status = VIRTIO_BLK_S_OK; int i; spin_lock(&vdpasim->lock); @@ -54,22 +197,7 @@ static void vdpasim_blk_work(struct work_struct *work) if (!vq->ready) continue; - while (vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, - &vq->in_iov, &vq->head, - GFP_ATOMIC) > 0) { - int write; - - vq->in_iov.i = vq->in_iov.used - 1; - write = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, - &status, 1); - if (write <= 0) - break; - - /* Make sure data is wrote before advancing index */ - smp_wmb(); - - vringh_complete_iotlb(&vq->vring, vq->head, write); - + while (vdpasim_blk_handle_req(vdpasim, vq)) { /* Make sure used is visible before rasing the interrupt. */ smp_wmb(); @@ -109,7 +237,7 @@ static int __init vdpasim_blk_init(void) dev_attr.config_size = sizeof(struct virtio_blk_config); dev_attr.get_config = vdpasim_blk_get_config; dev_attr.work_fn = vdpasim_blk_work; - dev_attr.buffer_size = PAGE_SIZE; + dev_attr.buffer_size = VDPASIM_BLK_CAPACITY << SECTOR_SHIFT; vdpasim_blk_dev = vdpasim_create(&dev_attr); if (IS_ERR(vdpasim_blk_dev)) { -- 2.7.4