Re: [PATCH] libs/foreignmemory: Implement on NetBSD

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Jan 12, 2021 at 07:12:31PM +0100, Manuel Bouyer wrote:
> From: Manuel Bouyer <bouyer@xxxxxxxxxx>
> 
> Implement foreignmemory interface on NetBSD. The compat interface is now used
> only on __sun__
> 
> Signed-off-by: Manuel Bouyer <bouyer@xxxxxxxxxx>
> ---
>  tools/libs/foreignmemory/Makefile  |  2 +-
>  tools/libs/foreignmemory/netbsd.c  | 75 ++++++++++++++++++++++++++----
>  tools/libs/foreignmemory/private.h |  6 +--
>  3 files changed, 69 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/libs/foreignmemory/Makefile 
> b/tools/libs/foreignmemory/Makefile
> index 13850f7988..f191cdbed0 100644
> --- a/tools/libs/foreignmemory/Makefile
> +++ b/tools/libs/foreignmemory/Makefile
> @@ -8,7 +8,7 @@ SRCS-y                 += core.c
>  SRCS-$(CONFIG_Linux)   += linux.c
>  SRCS-$(CONFIG_FreeBSD) += freebsd.c
>  SRCS-$(CONFIG_SunOS)   += compat.c solaris.c
> -SRCS-$(CONFIG_NetBSD)  += compat.c netbsd.c
> +SRCS-$(CONFIG_NetBSD)  += netbsd.c
>  SRCS-$(CONFIG_MiniOS)  += minios.c
>  
>  include $(XEN_ROOT)/tools/libs/libs.mk
> diff --git a/tools/libs/foreignmemory/netbsd.c 
> b/tools/libs/foreignmemory/netbsd.c
> index 54a418ebd6..c2a691daed 100644
> --- a/tools/libs/foreignmemory/netbsd.c
> +++ b/tools/libs/foreignmemory/netbsd.c
> @@ -19,7 +19,9 @@
>  
>  #include <unistd.h>
>  #include <fcntl.h>
> +#include <errno.h>
>  #include <sys/mman.h>
> +#include <sys/ioctl.h>
>  
>  #include "private.h"
>  
> @@ -66,15 +68,17 @@ int osdep_xenforeignmemory_close(xenforeignmemory_handle 
> *fmem)
>      return close(fd);
>  }
>  
> -void *osdep_map_foreign_batch(xenforeignmem_handle *fmem, uint32_t dom,
> -                              void *addr, int prot, int flags,
> -                              xen_pfn_t *arr, int num)
> +void *osdep_xenforeignmemory_map(xenforeignmemory_handle *fmem,
> +                                 uint32_t dom, void *addr,
> +                              int prot, int flags, size_t num,
> +                              const xen_pfn_t arr[/*num*/], int err[/*num*/])

Hard tabs in the last two lines added above.

> +
>  {
>      int fd = fmem->fd;
> -    privcmd_mmapbatch_t ioctlx;
> -    addr = mmap(addr, num*XC_PAGE_SIZE, prot, flags | MAP_ANON | MAP_SHARED, 
> -1, 0);
> +    privcmd_mmapbatch_v2_t ioctlx;

Nit: since you are already modifying this leaving an empty line here
would help readability IMO.

> +    addr = mmap(addr, num*PAGE_SIZE, prot, flags | MAP_ANON | MAP_SHARED, 
> -1, 0);
>      if ( addr == MAP_FAILED ) {
> -        PERROR("osdep_map_foreign_batch: mmap failed");
> +        PERROR("osdep_xenforeignmemory_map: mmap failed");
>          return NULL;
>      }
>  
> @@ -82,11 +86,12 @@ void *osdep_map_foreign_batch(xenforeignmem_handle *fmem, 
> uint32_t dom,
>      ioctlx.dom=dom;
>      ioctlx.addr=(unsigned long)addr;
>      ioctlx.arr=arr;
> -    if ( ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH, &ioctlx) < 0 )
> +    ioctlx.err=err;
> +    if ( ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH_V2, &ioctlx) < 0 )
>      {
>          int saved_errno = errno;
> -        PERROR("osdep_map_foreign_batch: ioctl failed");
> -        (void)munmap(addr, num*XC_PAGE_SIZE);
> +        PERROR("osdep_xenforeignmemory_map: ioctl failed");
> +        (void)munmap(addr, num*PAGE_SIZE);
>          errno = saved_errno;
>          return NULL;
>      }
> @@ -97,7 +102,57 @@ void *osdep_map_foreign_batch(xenforeignmem_handle *fmem, 
> uint32_t dom,
>  int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
>                                   void *addr, size_t num)
>  {
> -    return munmap(addr, num*XC_PAGE_SIZE);
> +    return munmap(addr, num*PAGE_SIZE);
> +}
> +
> +int osdep_xenforeignmemory_restrict(xenforeignmemory_handle *fmem,
> +                                    domid_t domid)
> +{
> +    errno = EOPNOTSUPP;
> +    return -1;
> +}
> +
> +int osdep_xenforeignmemory_unmap_resource(
> +    xenforeignmemory_handle *fmem, xenforeignmemory_resource_handle *fres)
> +{
> +    return fres ? munmap(fres->addr, fres->nr_frames << PAGE_SHIFT) : 0;
> +}
> +
> +int osdep_xenforeignmemory_map_resource(
> +    xenforeignmemory_handle *fmem, xenforeignmemory_resource_handle *fres)
> +{
> +    privcmd_mmap_resource_t mr = {
> +        .dom = fres->domid,
> +        .type = fres->type,
> +        .id = fres->id,
> +        .idx = fres->frame,
> +        .num = fres->nr_frames,
> +    };
> +    int rc;
> +
> +    fres->addr = mmap(fres->addr, fres->nr_frames << PAGE_SHIFT,
> +                      fres->prot, fres->flags | MAP_ANON | MAP_SHARED, -1, 
> 0);
> +    if ( fres->addr == MAP_FAILED )
> +        return -1;
> +
> +    mr.addr = (uintptr_t)fres->addr;
> +
> +    rc = ioctl(fmem->fd, IOCTL_PRIVCMD_MMAP_RESOURCE, &mr);
> +    if ( rc )
> +    {
> +        int saved_errno;
> +
> +        if ( errno != EOPNOTSUPP )

Seems like NetBSD will return EINVAL for unknown privcmd ioctls?

http://bxr.su/NetBSD/sys/arch/xen/xen/privcmd.c#802

This would make differentiating between a real error or a missing
ioctl impossible AFAICT, so I think you can remove the check for
EOPNOTSUPP?

> +            PERROR("ioctl failed");
> +
> +        saved_errno = errno;
> +        (void)osdep_xenforeignmemory_unmap_resource(fmem, fres);
> +        errno = saved_errno;
> +
> +        return -1;
> +    }
> +
> +    return 0;
>  }
>  
>  /*
> diff --git a/tools/libs/foreignmemory/private.h 
> b/tools/libs/foreignmemory/private.h
> index b522a2b86b..f7569d4f6b 100644
> --- a/tools/libs/foreignmemory/private.h
> +++ b/tools/libs/foreignmemory/private.h
> @@ -42,9 +42,9 @@ void *osdep_xenforeignmemory_map(xenforeignmemory_handle 
> *fmem,
>  int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
>                                   void *addr, size_t num);
>  
> -#if defined(__NetBSD__) || defined(__sun__)
> +#if defined(__sun__)
>  /* Strictly compat for those two only only */
> -void *compat_mapforeign_batch(xenforeignmem_handle *fmem, uint32_t dom,
> +void *osdep_map_foreign_batch(xenforeignmemory_handle *fmem, uint32_t dom,
>                                void *addr, int prot, int flags,
>                                xen_pfn_t *arr, int num);
>  #endif
> @@ -60,7 +60,7 @@ struct xenforeignmemory_resource_handle {
>      int flags;
>  };
>  
> -#ifndef __linux__
> +#if  !defined(__linux__) && !defined(__NetBSD__)

Since I got the FreeBSD support committed, you would have to rebase
the series and this should then become:

#ifdef __sun__

I think. The rest of the patch LGTM.

Thanks, Roger.