RE: [PATCH V0] mshv: pass struct mshv_user_mem_region by reference

Michael Kelley
2026-03-04T18:45:15Z

From: Mukesh R <mrathor@linux.microsoft.com> Sent: Tuesday, March 3, 2026 4:03 PM
>
> For unstated reasons, function mshv_partition_ioctl_set_memory passes
> struct mshv_user_mem_region by value instead of by reference. Change
> it to pass by reference.
>
> Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>

Reviewed-by: Michael Kelley <mhklinux@outlook.com>

> ---
> drivers/hv/mshv_root_main.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> index e6509c980763..87c5ffd2528d 100644
> --- a/drivers/hv/mshv_root_main.c
> +++ b/drivers/hv/mshv_root_main.c
> @@ -1289,7 +1289,7 @@ static int mshv_prepare_pinned_region(struct mshv_mem_region *region)
> */
> static long
> mshv_map_user_memory(struct mshv_partition *partition,
> - struct mshv_user_mem_region mem)
> + struct mshv_user_mem_region *mem)
> {
> struct mshv_mem_region *region;
> struct vm_area_struct *vma;
> @@ -1297,12 +1297,12 @@ mshv_map_user_memory(struct mshv_partition *partition,
> ulong mmio_pfn;
> long ret;
>
> - if (mem.flags & BIT(MSHV_SET_MEM_BIT_UNMAP) ||
> - !access_ok((const void __user *)mem.userspace_addr, mem.size))
> + if (mem->flags & BIT(MSHV_SET_MEM_BIT_UNMAP) ||
> + !access_ok((const void __user *)mem->userspace_addr, mem->size))
> return -EINVAL;
>
> mmap_read_lock(current->mm);
> - vma = vma_lookup(current->mm, mem.userspace_addr);
> + vma = vma_lookup(current->mm, mem->userspace_addr);
> is_mmio = vma ? !!(vma->vm_flags & (VM_IO | VM_PFNMAP)) : 0;
> mmio_pfn = is_mmio ? vma->vm_pgoff : 0;
> mmap_read_unlock(current->mm);
> @@ -1310,7 +1310,7 @@ mshv_map_user_memory(struct mshv_partition *partition,
> if (!vma)
> return -EINVAL;
>
> - ret = mshv_partition_create_region(partition, &mem, &region,
> + ret = mshv_partition_create_region(partition, mem, &region,
> is_mmio);
> if (ret)
> return ret;
> @@ -1355,25 +1355,25 @@ mshv_map_user_memory(struct mshv_partition *partition,
> /* Called for unmapping both the guest ram and the mmio space */
> static long
> mshv_unmap_user_memory(struct mshv_partition *partition,
> - struct mshv_user_mem_region mem)
> + struct mshv_user_mem_region *mem)
> {
> struct mshv_mem_region *region;
>
> - if (!(mem.flags & BIT(MSHV_SET_MEM_BIT_UNMAP)))
> + if (!(mem->flags & BIT(MSHV_SET_MEM_BIT_UNMAP)))
> return -EINVAL;
>
> spin_lock(&partition->pt_mem_regions_lock);
>
> - region = mshv_partition_region_by_gfn(partition, mem.guest_pfn);
> + region = mshv_partition_region_by_gfn(partition, mem->guest_pfn);
> if (!region) {
> spin_unlock(&partition->pt_mem_regions_lock);
> return -ENOENT;
> }
>
> /* Paranoia check */
> - if (region->start_uaddr != mem.userspace_addr ||
> - region->start_gfn != mem.guest_pfn ||
> - region->nr_pages != HVPFN_DOWN(mem.size)) {
> + if (region->start_uaddr != mem->userspace_addr ||
> + region->start_gfn != mem->guest_pfn ||
> + region->nr_pages != HVPFN_DOWN(mem->size)) {
> spin_unlock(&partition->pt_mem_regions_lock);
> return -EINVAL;
> }
> @@ -1404,9 +1404,9 @@ mshv_partition_ioctl_set_memory(struct mshv_partition *partition,
> return -EINVAL;
>
> if (mem.flags & BIT(MSHV_SET_MEM_BIT_UNMAP))
> - return mshv_unmap_user_memory(partition, mem);
> + return mshv_unmap_user_memory(partition, &mem);
>
> - return mshv_map_user_memory(partition, mem);
> + return mshv_map_user_memory(partition, &mem);
> }
>
> static long
> --
> 2.51.2.vfs.0.1
>