Re: [Qemu-devel] [PATCH v1] vhost-user: fix not send all hugepage files to vhost-user

[Paolo Bonzini]

On 17/12/2014 07:02, address@hidden wrote:
> From: linhaifeng <address@hidden>
> 
> If we create VM with two or more numa nodes qemu will create two
> or more hugepage files but qemu only send one hugepage file fd
> to vhost-user when VM's memory size is 2G and with two numa nodes.
> 
> Signed-off-by: linhaifeng <address@hidden>

The bug is in vhost_dev_assign_memory.  It doesn't check that the file
descriptor matches when merging regions.  Michael, does the merging
trigger in practice?  Can we just eliminate it?

Paolo

> ---
>  hw/virtio/vhost-user.c      | 78 
> ++++++++++++++++++++++++++++++---------------
>  hw/virtio/vhost.c           | 13 ++++++++
>  linux-headers/linux/vhost.h |  7 ++++
>  3 files changed, 73 insertions(+), 25 deletions(-)
> 
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index aefe0bb..439cbba 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -24,6 +24,10 @@
>  #include <linux/vhost.h>
>  
>  #define VHOST_MEMORY_MAX_NREGIONS    8
> +/* FIXME: same as the max number of numa node?*/
> +#define HUGEPAGE_MAX_FILES           8
> +
> +#define RAM_SHARED     (1 << 1)
>  
>  typedef enum VhostUserRequest {
>      VHOST_USER_NONE = 0,
> @@ -41,14 +45,15 @@ typedef enum VhostUserRequest {
>      VHOST_USER_SET_VRING_KICK = 12,
>      VHOST_USER_SET_VRING_CALL = 13,
>      VHOST_USER_SET_VRING_ERR = 14,
> -    VHOST_USER_MAX
> +    VHOST_USER_MMAP_HUGEPAGE_FILE = 15,
> +    VHOST_USER_UNMAP_HUGEPAGE_FILE = 16,
> +    VHOST_USER_MAX,
>  } VhostUserRequest;
>  
>  typedef struct VhostUserMemoryRegion {
>      uint64_t guest_phys_addr;
>      uint64_t memory_size;
>      uint64_t userspace_addr;
> -    uint64_t mmap_offset;
>  } VhostUserMemoryRegion;
>  
>  typedef struct VhostUserMemory {
> @@ -57,6 +62,16 @@ typedef struct VhostUserMemory {
>      VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
>  } VhostUserMemory;
>  
> +typedef struct HugepageMemoryInfo {
> +    uint64_t base_addr;
> +    uint64_t size;
> +}HugeMemInfo;
> +
> +typedef struct HugepageInfo {
> +    uint32_t num;
> +    HugeMemInfo files[HUGEPAGE_MAX_FILES];
> +}HugepageInfo;
> +
>  typedef struct VhostUserMsg {
>      VhostUserRequest request;
>  
> @@ -71,6 +86,7 @@ typedef struct VhostUserMsg {
>          struct vhost_vring_state state;
>          struct vhost_vring_addr addr;
>          VhostUserMemory memory;
> +        HugepageInfo huge_info;
>      };
>  } QEMU_PACKED VhostUserMsg;
>  
> @@ -104,7 +120,9 @@ static unsigned long int 
> ioctl_to_vhost_user_request[VHOST_USER_MAX] = {
>      VHOST_GET_VRING_BASE,   /* VHOST_USER_GET_VRING_BASE */
>      VHOST_SET_VRING_KICK,   /* VHOST_USER_SET_VRING_KICK */
>      VHOST_SET_VRING_CALL,   /* VHOST_USER_SET_VRING_CALL */
> -    VHOST_SET_VRING_ERR     /* VHOST_USER_SET_VRING_ERR */
> +    VHOST_SET_VRING_ERR,    /* VHOST_USER_SET_VRING_ERR */
> +    VHOST_MMAP_HUGEPAGE_FILE,  /* VHOST_USER_MMAP_HUGEPAGE_FILE */
> +    VHOST_UNMAP_HUGEPAGE_FILE, /* VHOST_USER_UNMAP_HUGEPAGE_FILE */
>  };
>  
>  static VhostUserRequest vhost_user_request_translate(unsigned long int 
> request)
> @@ -190,6 +208,7 @@ static int vhost_user_call(struct vhost_dev *dev, 
> unsigned long int request,
>      int fds[VHOST_MEMORY_MAX_NREGIONS];
>      int i, fd;
>      size_t fd_num = 0;
> +    RAMBlock *block;
>  
>      assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
>  
> @@ -213,37 +232,46 @@ static int vhost_user_call(struct vhost_dev *dev, 
> unsigned long int request,
>      case VHOST_RESET_OWNER:
>          break;
>  
> -    case VHOST_SET_MEM_TABLE:
> -        for (i = 0; i < dev->mem->nregions; ++i) {
> -            struct vhost_memory_region *reg = dev->mem->regions + i;
> -            ram_addr_t ram_addr;
> +    case VHOST_MMAP_HUGEPAGE_FILE:
> +        qemu_mutex_lock_ramlist();
>  
> -            assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> -            qemu_ram_addr_from_host((void *)(uintptr_t)reg->userspace_addr, 
> &ram_addr);
> -            fd = qemu_get_ram_fd(ram_addr);
> -            if (fd > 0) {
> -                msg.memory.regions[fd_num].userspace_addr = 
> reg->userspace_addr;
> -                msg.memory.regions[fd_num].memory_size  = reg->memory_size;
> -                msg.memory.regions[fd_num].guest_phys_addr = 
> reg->guest_phys_addr;
> -                msg.memory.regions[fd_num].mmap_offset = reg->userspace_addr 
> -
> -                    (uintptr_t) qemu_get_ram_block_host_ptr(ram_addr);
> -                assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
> -                fds[fd_num++] = fd;
> +        /* Get hugepage file informations */
> +        QTAILQ_FOREACH(block, &ram_list.blocks, next) {
> +            if (block->flags & RAM_SHARED && block->fd > 0) {
> +                msg.huge_info.files[fd_num].size = block->length;
> +                msg.huge_info.files[fd_num].base_addr = block->host;
> +                fds[fd_num++] = block->fd;
>              }
>          }
> +        msg.huge_info.num = fd_num;
>  
> -        msg.memory.nregions = fd_num;
> +        /* Calculate msg size */
> +        msg.size = sizeof(m.huge_info.num);
> +        msg.size += fd_num * sizeof(HugeMemInfo);
> +        
> +        qemu_mutex_unlock_ramlist();        
> +        break;
>  
> -        if (!fd_num) {
> -            error_report("Failed initializing vhost-user memory map\n"
> -                    "consider using -object memory-backend-file share=on\n");
> -            return -1;
> +    case VHOST_UNMAP_HUGEPAGE_FILE:
> +        /* Tell vhost-user to unmap all hugepage files. */
> +        break;
> +
> +    case VHOST_SET_MEM_TABLE:
> +        for (i = 0; i < dev->mem->nregions; i++) {
> +            struct vhost_memory_region *reg = dev->mem->regions + i;
> +
> +            assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> +
> +            msg.memory.regions[i].userspace_addr = reg->userspace_addr;
> +            msg.memory.regions[i].memory_size  = reg->memory_size;
> +            msg.memory.regions[i].guest_phys_addr = reg->guest_phys_addr;
> +            assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
>          }
>  
> +        msg.memory.nregions = i;
>          msg.size = sizeof(m.memory.nregions);
>          msg.size += sizeof(m.memory.padding);
> -        msg.size += fd_num * sizeof(VhostUserMemoryRegion);
> -
> +        msg.size += i * sizeof(VhostUserMemoryRegion);
>          break;
>  
>      case VHOST_SET_LOG_FD:
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 5a12861..b8eb341 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -1041,6 +1041,14 @@ int vhost_dev_start(struct vhost_dev *hdev, 
> VirtIODevice *vdev)
>      if (r < 0) {
>          goto fail_features;
>      }
> +    if (hdev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER) {
> +        r = hdev->vhost_ops->vhost_call(hdev, VHOST_MMAP_HUGEPAGE_FILE, 
> +            NULL);
> +        if (r < 0) {
> +            r = -errno;
> +            goto fail_mem;
> +        }    
> +    }
>      r = hdev->vhost_ops->vhost_call(hdev, VHOST_SET_MEM_TABLE, hdev->mem);
>      if (r < 0) {
>          r = -errno;
> @@ -1101,5 +1109,10 @@ void vhost_dev_stop(struct vhost_dev *hdev, 
> VirtIODevice *vdev)
>      g_free(hdev->log);
>      hdev->log = NULL;
>      hdev->log_size = 0;
> +
> +    if (hdev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER) {
> +        (void)hdev->vhost_ops->vhost_call(hdev, VHOST_MMAP_HUGEPAGE_FILE, 
> +            NULL);   
> +    }    
>  }
>  
> diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h
> index c656f61..bb72811 100644
> --- a/linux-headers/linux/vhost.h
> +++ b/linux-headers/linux/vhost.h
> @@ -113,6 +113,13 @@ struct vhost_memory {
>  /* Set eventfd to signal an error */
>  #define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
>  
> +/* Tell vhost-user to mmap hugepage file */
> +#define VHOST_MMAP_HUGEPAGE_FILE _IOW(VHOST_VIRTIO, 0x23, int)
> +/* Tell vhost-user to unmap hugepage file */
> +#define VHOST_UNMAP_HUGEPAGE_FILE _IOW(VHOST_VIRTIO, 0x24, int)
> +
> +#define VHOST_THREAD_ID _IOR(VHOST_VIRTIO, 0x25, struct vhost_vring_thread)
> +
>  /* VHOST_NET specific defines */
>  
>  /* Attach virtio net ring to a raw socket, or tap device.
>