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Re: [RFC v3 11/19] vfio-user: get region info
From: |
Alex Williamson |
Subject: |
Re: [RFC v3 11/19] vfio-user: get region info |
Date: |
Fri, 19 Nov 2021 15:42:28 -0700 |
On Mon, 8 Nov 2021 16:46:39 -0800
John Johnson <john.g.johnson@oracle.com> wrote:
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> ---
> hw/vfio/user-protocol.h | 14 ++++++++++++
> include/hw/vfio/vfio-common.h | 4 +++-
> hw/vfio/common.c | 30 +++++++++++++++++++++++++-
> hw/vfio/user.c | 50
> +++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 96 insertions(+), 2 deletions(-)
>
> diff --git a/hw/vfio/user-protocol.h b/hw/vfio/user-protocol.h
> index 13e44eb..104bf4f 100644
> --- a/hw/vfio/user-protocol.h
> +++ b/hw/vfio/user-protocol.h
> @@ -95,4 +95,18 @@ typedef struct {
> uint32_t cap_offset;
> } VFIOUserDeviceInfo;
>
> +/*
> + * VFIO_USER_DEVICE_GET_REGION_INFO
> + * imported from struct_vfio_region_info
> + */
> +typedef struct {
> + VFIOUserHdr hdr;
> + uint32_t argsz;
> + uint32_t flags;
> + uint32_t index;
> + uint32_t cap_offset;
> + uint64_t size;
> + uint64_t offset;
> +} VFIOUserRegionInfo;
> +
> #endif /* VFIO_USER_PROTOCOL_H */
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 224dbf8..e2d7ee1 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -56,6 +56,7 @@ typedef struct VFIORegion {
> uint32_t nr_mmaps;
> VFIOMmap *mmaps;
> uint8_t nr; /* cache the region number for debug */
> + int remfd; /* fd if exported from remote process */
> } VFIORegion;
>
> typedef struct VFIOMigration {
> @@ -150,8 +151,9 @@ typedef struct VFIODevice {
> VFIOMigration *migration;
> Error *migration_blocker;
> OnOffAuto pre_copy_dirty_page_tracking;
> - struct vfio_region_info **regions;
> VFIOProxy *proxy;
> + struct vfio_region_info **regions;
> + int *regfds;
> } VFIODevice;
>
> struct VFIODeviceOps {
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 41fdd78..47ec28f 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -40,6 +40,7 @@
> #include "trace.h"
> #include "qapi/error.h"
> #include "migration/migration.h"
> +#include "hw/vfio/user.h"
>
> VFIOGroupList vfio_group_list =
> QLIST_HEAD_INITIALIZER(vfio_group_list);
> @@ -1491,6 +1492,16 @@ bool vfio_get_info_dma_avail(struct
> vfio_iommu_type1_info *info,
> return true;
> }
>
> +static int vfio_get_region_info_remfd(VFIODevice *vbasedev, int index)
> +{
> + struct vfio_region_info *info;
> +
> + if (vbasedev->regions == NULL || vbasedev->regions[index] == NULL) {
> + vfio_get_region_info(vbasedev, index, &info);
> + }
> + return vbasedev->regfds != NULL ? vbasedev->regfds[index] : -1;
> +}
This patch is really obscure due to the region info fd being added many
patches ago and only now being used.
Do we really want a parallel array to regions for storing these fds?
Why do we call an array of these fds "regfds" but a single one "remfd"?
Ugh, why do we have both the regfds array and a remfd per VFIORegion?
TBH, I'm still not sure why we're caching region infos at all, this
seems to be gratuitously bloated.
> +
> static int vfio_setup_region_sparse_mmaps(VFIORegion *region,
> struct vfio_region_info *info)
> {
> @@ -1544,6 +1555,7 @@ int vfio_region_setup(Object *obj, VFIODevice
> *vbasedev, VFIORegion *region,
> region->size = info->size;
> region->fd_offset = info->offset;
> region->nr = index;
> + region->remfd = vfio_get_region_info_remfd(vbasedev, index);
Why didn't we just get an fd back from vfio_get_region_info() that we
could use here?
>
> if (region->size) {
> region->mem = g_new0(MemoryRegion, 1);
> @@ -1587,6 +1599,7 @@ int vfio_region_mmap(VFIORegion *region)
> {
> int i, prot = 0;
> char *name;
> + int fd;
>
> if (!region->mem) {
> return 0;
> @@ -1595,9 +1608,11 @@ int vfio_region_mmap(VFIORegion *region)
> prot |= region->flags & VFIO_REGION_INFO_FLAG_READ ? PROT_READ : 0;
> prot |= region->flags & VFIO_REGION_INFO_FLAG_WRITE ? PROT_WRITE : 0;
>
> + fd = region->remfd != -1 ? region->remfd : region->vbasedev->fd;
Gack, why can't VFIORegion.fd be either the remote process fd or the
vbasedevfd to avoid all these switches? Thanks,
Alex
> +
> for (i = 0; i < region->nr_mmaps; i++) {
> region->mmaps[i].mmap = mmap(NULL, region->mmaps[i].size, prot,
> - MAP_SHARED, region->vbasedev->fd,
> + MAP_SHARED, fd,
> region->fd_offset +
> region->mmaps[i].offset);
> if (region->mmaps[i].mmap == MAP_FAILED) {
> @@ -2379,10 +2394,17 @@ void vfio_put_base_device(VFIODevice *vbasedev)
> int i;
>
> for (i = 0; i < vbasedev->num_regions; i++) {
> + if (vbasedev->regfds != NULL && vbasedev->regfds[i] != -1) {
> + close(vbasedev->regfds[i]);
> + }
> g_free(vbasedev->regions[i]);
> }
> g_free(vbasedev->regions);
> vbasedev->regions = NULL;
> + if (vbasedev->regfds != NULL) {
> + g_free(vbasedev->regfds);
> + vbasedev->regfds = NULL;
> + }
> }
>
> if (!vbasedev->group) {
> @@ -2405,6 +2427,9 @@ int vfio_get_region_info(VFIODevice *vbasedev, int
> index,
> if (vbasedev->regions == NULL) {
> vbasedev->regions = g_new0(struct vfio_region_info *,
> vbasedev->num_regions);
> + if (vbasedev->proxy != NULL) {
> + vbasedev->regfds = g_new0(int, vbasedev->num_regions);
> + }
> }
> /* check cache */
> if (vbasedev->regions[index] != NULL) {
> @@ -2441,6 +2466,9 @@ retry:
> /* fill cache */
> vbasedev->regions[index] = g_malloc0(argsz);
> memcpy(vbasedev->regions[index], *info, argsz);
> + if (vbasedev->regfds != NULL) {
> + vbasedev->regfds[index] = fd;
> + }
>
> return 0;
> }
> diff --git a/hw/vfio/user.c b/hw/vfio/user.c
> index ed2a4d7..b40c4ed 100644
> --- a/hw/vfio/user.c
> +++ b/hw/vfio/user.c
> @@ -923,6 +923,40 @@ static int vfio_user_get_info(VFIOProxy *proxy, struct
> vfio_device_info *info)
> return 0;
> }
>
> +static int vfio_user_get_region_info(VFIOProxy *proxy,
> + struct vfio_region_info *info,
> + VFIOUserFDs *fds)
> +{
> + g_autofree VFIOUserRegionInfo *msgp = NULL;
> + uint32_t size;
> +
> + /* data returned can be larger than vfio_region_info */
> + if (info->argsz < sizeof(*info)) {
> + error_printf("vfio_user_get_region_info argsz too small\n");
> + return -EINVAL;
> + }
> + if (fds != NULL && fds->send_fds != 0) {
> + error_printf("vfio_user_get_region_info can't send FDs\n");
> + return -EINVAL;
> + }
> +
> + size = info->argsz + sizeof(VFIOUserHdr);
> + msgp = g_malloc0(size);
> +
> + vfio_user_request_msg(&msgp->hdr, VFIO_USER_DEVICE_GET_REGION_INFO,
> + sizeof(*msgp), 0);
> + msgp->argsz = info->argsz;
> + msgp->index = info->index;
> +
> + vfio_user_send_wait(proxy, &msgp->hdr, fds, size, false);
> + if (msgp->hdr.flags & VFIO_USER_ERROR) {
> + return -msgp->hdr.error_reply;
> + }
> +
> + memcpy(info, &msgp->argsz, info->argsz);
> + return 0;
> +}
> +
>
> /*
> * Socket-based io_ops
> @@ -941,7 +975,23 @@ static int vfio_user_io_get_info(VFIODevice *vbasedev,
> return VDEV_VALID_INFO(vbasedev, info);
> }
>
> +static int vfio_user_io_get_region_info(VFIODevice *vbasedev,
> + struct vfio_region_info *info,
> + int *fd)
> +{
> + int ret;
> + VFIOUserFDs fds = { 0, 1, fd};
> +
> + ret = vfio_user_get_region_info(vbasedev->proxy, info, &fds);
> + if (ret) {
> + return ret;
> + }
> +
> + return VDEV_VALID_REGION_INFO(vbasedev, info, fd);
> +}
> +
> VFIODevIO vfio_dev_io_sock = {
> .get_info = vfio_user_io_get_info,
> + .get_region_info = vfio_user_io_get_region_info,
> };
>
- [RFC v3 00/19] vfio-user client, John Johnson, 2021/11/08
- [RFC v3 13/19] vfio-user: pci_user_realize PCI setup, John Johnson, 2021/11/08
- [RFC v3 11/19] vfio-user: get region info, John Johnson, 2021/11/08
- Re: [RFC v3 11/19] vfio-user: get region info,
Alex Williamson <=
- [RFC v3 06/19] vfio-user: Define type vfio_user_pci_dev_info, John Johnson, 2021/11/08
- [RFC v3 04/19] Add device IO ops vector, John Johnson, 2021/11/08
- [RFC v3 09/19] vfio-user: define socket send functions, John Johnson, 2021/11/08
- [RFC v3 03/19] Add container IO ops vector, John Johnson, 2021/11/08
- [RFC v3 02/19] vfio-user: add VFIO base abstract class, John Johnson, 2021/11/08
- [RFC v3 07/19] vfio-user: connect vfio proxy to remote server, John Johnson, 2021/11/08