diff mbox series

[v1.1,03/10] tools/libxg: Drop stale p2m logic from ARM's meminit()

Message ID 20210212200139.26911-1-andrew.cooper3@citrix.com (mailing list archive)
State New
Headers show
Series None | expand

Commit Message

Andrew Cooper Feb. 12, 2021, 8:01 p.m. UTC
Various version of gcc, when compiling with -Og, complain:

  xg_dom_arm.c: In function 'meminit':
  xg_dom_arm.c:420:19: error: 'p2m_size' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    420 |     dom->p2m_size = p2m_size;
        |     ~~~~~~~~~~~~~~^~~~~~~~~~

This is actually entirely stale code since ee21f10d70^..97e34ad22d which
removed the 1:1 identity p2m for translated domains.

Drop the write of d->p2m_size, and the p2m_size local variable.  Reposition
the p2m_size field in struct xc_dom_image and correct some stale
documentation.

This change really ought to have been part of the original cleanup series.

No actual change to how ARM domains are constructed.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Ian Jackson <iwj@xenproject.org>
CC: Wei Liu <wl@xen.org>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien@xen.org>

v2:
 * Delete stale p2m_size infrastructure.
---
 tools/include/xenguest.h      | 5 ++---
 tools/libs/guest/xg_dom_arm.c | 5 -----
 2 files changed, 2 insertions(+), 8 deletions(-)

Comments

Ian Jackson Feb. 16, 2021, 4 p.m. UTC | #1
Andrew Cooper writes ("[PATCH v1.1 03/10] tools/libxg: Drop stale p2m logic from ARM's meminit()"):
> Various version of gcc, when compiling with -Og, complain:
> 
>   xg_dom_arm.c: In function 'meminit':
>   xg_dom_arm.c:420:19: error: 'p2m_size' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>     420 |     dom->p2m_size = p2m_size;
>         |     ~~~~~~~~~~~~~~^~~~~~~~~~
> 
> This is actually entirely stale code since ee21f10d70^..97e34ad22d which
> removed the 1:1 identity p2m for translated domains.
> 
> Drop the write of d->p2m_size, and the p2m_size local variable.  Reposition
> the p2m_size field in struct xc_dom_image and correct some stale
> documentation.
> 
> This change really ought to have been part of the original cleanup series.
> 
> No actual change to how ARM domains are constructed.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Release-Acked-by: Ian Jackson <iwj@xenproject.org>
Julien Grall Feb. 16, 2021, 4:27 p.m. UTC | #2
Hi Andrew,

On 12/02/2021 20:01, Andrew Cooper wrote:
> Various version of gcc, when compiling with -Og, complain:
> 
>    xg_dom_arm.c: In function 'meminit':
>    xg_dom_arm.c:420:19: error: 'p2m_size' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>      420 |     dom->p2m_size = p2m_size;
>          |     ~~~~~~~~~~~~~~^~~~~~~~~~
> 
> This is actually entirely stale code since ee21f10d70^..97e34ad22d which
> removed the 1:1 identity p2m for translated domains.
> 
> Drop the write of d->p2m_size, and the p2m_size local variable.  Reposition
> the p2m_size field in struct xc_dom_image and correct some stale
> documentation.
> 
> This change really ought to have been part of the original cleanup series.
> 
> No actual change to how ARM domains are constructed.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

> ---
> CC: Ian Jackson <iwj@xenproject.org>
> CC: Wei Liu <wl@xen.org>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Julien Grall <julien@xen.org>
> 
> v2:
>   * Delete stale p2m_size infrastructure.
> ---
>   tools/include/xenguest.h      | 5 ++---
>   tools/libs/guest/xg_dom_arm.c | 5 -----
>   2 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h
> index 775cf34c04..217022b6e7 100644
> --- a/tools/include/xenguest.h
> +++ b/tools/include/xenguest.h
> @@ -145,6 +145,7 @@ struct xc_dom_image {
>        * eventually copied into guest context.
>        */
>       xen_pfn_t *pv_p2m;
> +    xen_pfn_t p2m_size;         /* number of pfns covered by pv_p2m */
>   
>       /* physical memory
>        *
> @@ -154,12 +155,10 @@ struct xc_dom_image {
>        *
>        * An ARM guest has GUEST_RAM_BANKS regions of RAM, with
>        * rambank_size[i] pages in each. The lowest RAM address
> -     * (corresponding to the base of the p2m arrays above) is stored
> -     * in rambase_pfn.
> +     * is stored in rambase_pfn.
>        */
>       xen_pfn_t rambase_pfn;
>       xen_pfn_t total_pages;
> -    xen_pfn_t p2m_size;         /* number of pfns covered by p2m */
>       struct xc_dom_phys *phys_pages;
>   #if defined (__arm__) || defined(__aarch64__)
>       xen_pfn_t rambank_size[GUEST_RAM_BANKS];
> diff --git a/tools/libs/guest/xg_dom_arm.c b/tools/libs/guest/xg_dom_arm.c
> index 94948d2b20..b4c24f15fb 100644
> --- a/tools/libs/guest/xg_dom_arm.c
> +++ b/tools/libs/guest/xg_dom_arm.c
> @@ -373,7 +373,6 @@ static int meminit(struct xc_dom_image *dom)
>       const uint64_t modsize = dtb_size + ramdisk_size;
>       const uint64_t ram128mb = bankbase[0] + (128<<20);
>   
> -    xen_pfn_t p2m_size;
>       uint64_t bank0end;
>   
>       assert(dom->rambase_pfn << XC_PAGE_SHIFT == bankbase[0]);
> @@ -409,16 +408,12 @@ static int meminit(struct xc_dom_image *dom)
>   
>           ramsize -= banksize;
>   
> -        p2m_size = ( bankbase[i] + banksize - bankbase[0] ) >> XC_PAGE_SHIFT;
> -
>           dom->rambank_size[i] = banksize >> XC_PAGE_SHIFT;
>       }
>   
>       assert(dom->rambank_size[0] != 0);
>       assert(ramsize == 0); /* Too much RAM is rejected above */
>   
> -    dom->p2m_size = p2m_size;
> -
>       /* setup initial p2m and allocate guest memory */
>       for ( i = 0; i < GUEST_RAM_BANKS && dom->rambank_size[i]; i++ )
>       {
>
diff mbox series

Patch

diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h
index 775cf34c04..217022b6e7 100644
--- a/tools/include/xenguest.h
+++ b/tools/include/xenguest.h
@@ -145,6 +145,7 @@  struct xc_dom_image {
      * eventually copied into guest context.
      */
     xen_pfn_t *pv_p2m;
+    xen_pfn_t p2m_size;         /* number of pfns covered by pv_p2m */
 
     /* physical memory
      *
@@ -154,12 +155,10 @@  struct xc_dom_image {
      *
      * An ARM guest has GUEST_RAM_BANKS regions of RAM, with
      * rambank_size[i] pages in each. The lowest RAM address
-     * (corresponding to the base of the p2m arrays above) is stored
-     * in rambase_pfn.
+     * is stored in rambase_pfn.
      */
     xen_pfn_t rambase_pfn;
     xen_pfn_t total_pages;
-    xen_pfn_t p2m_size;         /* number of pfns covered by p2m */
     struct xc_dom_phys *phys_pages;
 #if defined (__arm__) || defined(__aarch64__)
     xen_pfn_t rambank_size[GUEST_RAM_BANKS];
diff --git a/tools/libs/guest/xg_dom_arm.c b/tools/libs/guest/xg_dom_arm.c
index 94948d2b20..b4c24f15fb 100644
--- a/tools/libs/guest/xg_dom_arm.c
+++ b/tools/libs/guest/xg_dom_arm.c
@@ -373,7 +373,6 @@  static int meminit(struct xc_dom_image *dom)
     const uint64_t modsize = dtb_size + ramdisk_size;
     const uint64_t ram128mb = bankbase[0] + (128<<20);
 
-    xen_pfn_t p2m_size;
     uint64_t bank0end;
 
     assert(dom->rambase_pfn << XC_PAGE_SHIFT == bankbase[0]);
@@ -409,16 +408,12 @@  static int meminit(struct xc_dom_image *dom)
 
         ramsize -= banksize;
 
-        p2m_size = ( bankbase[i] + banksize - bankbase[0] ) >> XC_PAGE_SHIFT;
-
         dom->rambank_size[i] = banksize >> XC_PAGE_SHIFT;
     }
 
     assert(dom->rambank_size[0] != 0);
     assert(ramsize == 0); /* Too much RAM is rejected above */
 
-    dom->p2m_size = p2m_size;
-
     /* setup initial p2m and allocate guest memory */
     for ( i = 0; i < GUEST_RAM_BANKS && dom->rambank_size[i]; i++ )
     {