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Re: [Qemu-devel] [PATCH] vhost-user: modify SET_LOG_BASE to pass mmap si
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH] vhost-user: modify SET_LOG_BASE to pass mmap size and offset |
Date: |
Wed, 11 Nov 2015 09:32:17 -0500 (EST) |
Hi
----- Original Message -----
> Unlike the kernel, vhost-user application accesses log table by
> mmaping it to its user space. This change adds two new fields to
> VhostUserMsg payload: mmap_size, and mmap_offset and make QEMU to
> pass the to vhost-user application in VHOST_USER_SET_LOG_BASE
> request.
>
> Signed-off-by: Victor Kaplansky <address@hidden>
What's the motivation for doing this? The offset is always 0, and the size must
at least match the size of VM memory.
>
> ---
> hw/virtio/vhost-user.c | 11 +++++++++--
> tests/vhost-user-test.c | 8 ++++++++
> docs/specs/vhost-user.txt | 8 +++++++-
> 3 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 83c84f1..46c63bc 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -75,6 +75,11 @@ typedef struct VhostUserMemory {
> VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
> } VhostUserMemory;
>
> +typedef struct VhostUserLog {
> + uint64_t mmap_size;
> + uint64_t mmap_offset;
> +} VhostUserLog;
> +
> typedef struct VhostUserMsg {
> VhostUserRequest request;
>
> @@ -89,6 +94,7 @@ typedef struct VhostUserMsg {
> struct vhost_vring_state state;
> struct vhost_vring_addr addr;
> VhostUserMemory memory;
> + VhostUserLog log;
> } payload;
> } QEMU_PACKED VhostUserMsg;
>
> @@ -200,8 +206,9 @@ static int vhost_user_set_log_base(struct vhost_dev *dev,
> uint64_t base,
> VhostUserMsg msg = {
> .request = VHOST_USER_SET_LOG_BASE,
> .flags = VHOST_USER_VERSION,
> - .payload.u64 = base,
> - .size = sizeof(msg.payload.u64),
> + .payload.log.mmap_size = log->size,
> + .payload.log.mmap_offset = 0,
> + .size = sizeof(msg.payload.log),
> };
>
> if (shmfd && log->fd != -1) {
> diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
> index b6dde75..f005ecf 100644
> --- a/tests/vhost-user-test.c
> +++ b/tests/vhost-user-test.c
> @@ -86,6 +86,11 @@ typedef struct VhostUserMemory {
> VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
> } VhostUserMemory;
>
> +typedef struct VhostUserLog {
> + uint64_t mmap_size;
> + uint64_t mmap_offset;
> +} VhostUserLog;
> +
> typedef struct VhostUserMsg {
> VhostUserRequest request;
>
> @@ -94,10 +99,13 @@ typedef struct VhostUserMsg {
> uint32_t flags;
> uint32_t size; /* the following payload size */
> union {
> +#define VHOST_USER_VRING_IDX_MASK (0xff)
> +#define VHOST_USER_VRING_NOFD_MASK (0x1<<8)
> uint64_t u64;
> struct vhost_vring_state state;
> struct vhost_vring_addr addr;
> VhostUserMemory memory;
> + VhostUserLog log;
> } payload;
> } QEMU_PACKED VhostUserMsg;
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index e0d71e2..eb8f2b2 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -98,6 +98,7 @@ typedef struct VhostUserMsg {
> struct vhost_vring_state state;
> struct vhost_vring_addr addr;
> VhostUserMemory memory;
> + VhostUserLog log;
> };
> } QEMU_PACKED VhostUserMsg;
>
> @@ -282,7 +283,12 @@ Message types
> Master payload: u64
> Slave payload: N/A
>
> - Sets the logging base address.
> + Sets logging shared memory space.
> + When slave has VHOST_USER_PROTOCOL_F_LOG_SHMFD protocol
> + feature, the log memory fd is provided in the ancillary data of
> + VHOST_USER_SET_LOG_BASE message, the size and offset of shared
> + memory area provided in the message.
> +
>
> * VHOST_USER_SET_LOG_FD
>
> --
> --Victor
>