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[PATCH] tools/libxc: Drop copy-in in xc_physinfo()

Andrew Cooper posted 1 patch 2 years, 4 months ago
Test gitlab-ci passed
Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20211223162244.16198-1-andrew.cooper3@citrix.com
tools/libs/ctrl/xc_misc.c | 2 --
tools/libs/light/libxl.c  | 2 +-
tools/libs/stat/xenstat.c | 2 +-
tools/misc/xenpm.c        | 2 +-
tools/xenmon/xenbaked.c   | 2 +-
tools/xentrace/xentrace.c | 2 +-
6 files changed, 5 insertions(+), 7 deletions(-)
[PATCH] tools/libxc: Drop copy-in in xc_physinfo()
Posted by Andrew Cooper 2 years, 4 months ago 
The first thing XEN_SYSCTL_physinfo does is zero op->u.physinfo.

Do not copy-in.  It's pointless, and most callers don't initialise their
xc_physinfo_t buffer to begin with.  Remove the pointless zeroing from the
remaining callers.

Spotted by Coverity.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Anthony PERARD <anthony.perard@citrix.com>
CC: Juergen Gross <jgross@suse.com>
---
 tools/libs/ctrl/xc_misc.c | 2 --
 tools/libs/light/libxl.c  | 2 +-
 tools/libs/stat/xenstat.c | 2 +-
 tools/misc/xenpm.c        | 2 +-
 tools/xenmon/xenbaked.c   | 2 +-
 tools/xentrace/xentrace.c | 2 +-
 6 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/tools/libs/ctrl/xc_misc.c b/tools/libs/ctrl/xc_misc.c
index 3820394413a9..265f15ec2da3 100644
--- a/tools/libs/ctrl/xc_misc.c
+++ b/tools/libs/ctrl/xc_misc.c
@@ -195,8 +195,6 @@ int xc_physinfo(xc_interface *xch,
 
     sysctl.cmd = XEN_SYSCTL_physinfo;
 
-    memcpy(&sysctl.u.physinfo, put_info, sizeof(*put_info));
-
     if ( (ret = do_sysctl(xch, &sysctl)) != 0 )
         return ret;
 
diff --git a/tools/libs/light/libxl.c b/tools/libs/light/libxl.c
index a77aa856fdd6..667ae6409be7 100644
--- a/tools/libs/light/libxl.c
+++ b/tools/libs/light/libxl.c
@@ -351,7 +351,7 @@ const char *libxl_defbool_to_string(libxl_defbool b)
 /******************************************************************************/
 int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
 {
-    xc_physinfo_t xcphysinfo = { 0 };
+    xc_physinfo_t xcphysinfo;
     int rc;
     long l;
     GC_INIT(ctx);
diff --git a/tools/libs/stat/xenstat.c b/tools/libs/stat/xenstat.c
index e49689aa2da9..8bab2e66a7fe 100644
--- a/tools/libs/stat/xenstat.c
+++ b/tools/libs/stat/xenstat.c
@@ -135,7 +135,7 @@ xenstat_node *xenstat_get_node(xenstat_handle * handle, unsigned int flags)
 {
 #define DOMAIN_CHUNK_SIZE 256
 	xenstat_node *node;
-	xc_physinfo_t physinfo = { 0 };
+	xc_physinfo_t physinfo;
 	xc_domaininfo_t domaininfo[DOMAIN_CHUNK_SIZE];
 	int new_domains;
 	unsigned int i;
diff --git a/tools/misc/xenpm.c b/tools/misc/xenpm.c
index d0191d498484..4f8cde690a7c 100644
--- a/tools/misc/xenpm.c
+++ b/tools/misc/xenpm.c
@@ -1244,7 +1244,7 @@ struct {
 int main(int argc, char *argv[])
 {
     int i, ret = 0;
-    xc_physinfo_t physinfo = { 0 };
+    xc_physinfo_t physinfo;
     int nr_matches = 0;
     int matches_main_options[ARRAY_SIZE(main_options)];
 
diff --git a/tools/xenmon/xenbaked.c b/tools/xenmon/xenbaked.c
index 1ed34334c824..7591de7c609f 100644
--- a/tools/xenmon/xenbaked.c
+++ b/tools/xenmon/xenbaked.c
@@ -436,7 +436,7 @@ static struct t_struct *map_tbufs(unsigned long tbufs_mfn, unsigned int num,
  */
 static unsigned int get_num_cpus(void)
 {
-    xc_physinfo_t physinfo = { 0 };
+    xc_physinfo_t physinfo;
     xc_interface *xc_handle = xc_interface_open(0,0,0);
     int ret;
 
diff --git a/tools/xentrace/xentrace.c b/tools/xentrace/xentrace.c
index a8903ebf4625..864e30d50cc3 100644
--- a/tools/xentrace/xentrace.c
+++ b/tools/xentrace/xentrace.c
@@ -589,7 +589,7 @@ static void set_evt_mask(uint32_t mask)
  */
 static unsigned int get_num_cpus(void)
 {
-    xc_physinfo_t physinfo = { 0 };
+    xc_physinfo_t physinfo;
     int ret;
     
     ret = xc_physinfo(xc_handle, &physinfo);
-- 
2.11.0
RE: [PATCH] tools/libxc: Drop copy-in in xc_physinfo()
Posted by Wei Chen 2 years, 3 months ago 
Hi Andrew,

> -----Original Message-----
> From: Xen-devel <xen-devel-bounces@lists.xenproject.org> On Behalf Of
> Andrew Cooper
> Sent: 2021年12月24日 0:23
> To: Xen-devel <xen-devel@lists.xenproject.org>
> Cc: Andrew Cooper <andrew.cooper3@citrix.com>; Anthony PERARD
> <anthony.perard@citrix.com>; Juergen Gross <jgross@suse.com>
> Subject: [PATCH] tools/libxc: Drop copy-in in xc_physinfo()
> 
> The first thing XEN_SYSCTL_physinfo does is zero op->u.physinfo.
> 
> Do not copy-in.  It's pointless, and most callers don't initialise their
> xc_physinfo_t buffer to begin with.  Remove the pointless zeroing from the
> remaining callers.
> 
> Spotted by Coverity.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Anthony PERARD <anthony.perard@citrix.com>
> CC: Juergen Gross <jgross@suse.com>
> ---
>  tools/libs/ctrl/xc_misc.c | 2 --
>  tools/libs/light/libxl.c  | 2 +-
>  tools/libs/stat/xenstat.c | 2 +-
>  tools/misc/xenpm.c        | 2 +-
>  tools/xenmon/xenbaked.c   | 2 +-
>  tools/xentrace/xentrace.c | 2 +-
>  6 files changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/libs/ctrl/xc_misc.c b/tools/libs/ctrl/xc_misc.c
> index 3820394413a9..265f15ec2da3 100644
> --- a/tools/libs/ctrl/xc_misc.c
> +++ b/tools/libs/ctrl/xc_misc.c
> @@ -195,8 +195,6 @@ int xc_physinfo(xc_interface *xch,
> 
>      sysctl.cmd = XEN_SYSCTL_physinfo;
> 
> -    memcpy(&sysctl.u.physinfo, put_info, sizeof(*put_info));
> -
>      if ( (ret = do_sysctl(xch, &sysctl)) != 0 )
>          return ret;
> 
> diff --git a/tools/libs/light/libxl.c b/tools/libs/light/libxl.c
> index a77aa856fdd6..667ae6409be7 100644
> --- a/tools/libs/light/libxl.c
> +++ b/tools/libs/light/libxl.c
> @@ -351,7 +351,7 @@ const char *libxl_defbool_to_string(libxl_defbool b)
> 
> /*************************************************************************
> *****/
>  int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
>  {
> -    xc_physinfo_t xcphysinfo = { 0 };
> +    xc_physinfo_t xcphysinfo;
>      int rc;
>      long l;
>      GC_INIT(ctx);
> diff --git a/tools/libs/stat/xenstat.c b/tools/libs/stat/xenstat.c
> index e49689aa2da9..8bab2e66a7fe 100644
> --- a/tools/libs/stat/xenstat.c
> +++ b/tools/libs/stat/xenstat.c
> @@ -135,7 +135,7 @@ xenstat_node *xenstat_get_node(xenstat_handle * handle,
> unsigned int flags)
>  {
>  #define DOMAIN_CHUNK_SIZE 256
>  	xenstat_node *node;
> -	xc_physinfo_t physinfo = { 0 };
> +	xc_physinfo_t physinfo;
>  	xc_domaininfo_t domaininfo[DOMAIN_CHUNK_SIZE];
>  	int new_domains;
>  	unsigned int i;
> diff --git a/tools/misc/xenpm.c b/tools/misc/xenpm.c
> index d0191d498484..4f8cde690a7c 100644
> --- a/tools/misc/xenpm.c
> +++ b/tools/misc/xenpm.c
> @@ -1244,7 +1244,7 @@ struct {
>  int main(int argc, char *argv[])
>  {
>      int i, ret = 0;
> -    xc_physinfo_t physinfo = { 0 };
> +    xc_physinfo_t physinfo;
>      int nr_matches = 0;
>      int matches_main_options[ARRAY_SIZE(main_options)];
> 
> diff --git a/tools/xenmon/xenbaked.c b/tools/xenmon/xenbaked.c
> index 1ed34334c824..7591de7c609f 100644
> --- a/tools/xenmon/xenbaked.c
> +++ b/tools/xenmon/xenbaked.c
> @@ -436,7 +436,7 @@ static struct t_struct *map_tbufs(unsigned long
> tbufs_mfn, unsigned int num,
>   */
>  static unsigned int get_num_cpus(void)
>  {
> -    xc_physinfo_t physinfo = { 0 };
> +    xc_physinfo_t physinfo;
>      xc_interface *xc_handle = xc_interface_open(0,0,0);
>      int ret;
> 
> diff --git a/tools/xentrace/xentrace.c b/tools/xentrace/xentrace.c
> index a8903ebf4625..864e30d50cc3 100644
> --- a/tools/xentrace/xentrace.c
> +++ b/tools/xentrace/xentrace.c
> @@ -589,7 +589,7 @@ static void set_evt_mask(uint32_t mask)
>   */
>  static unsigned int get_num_cpus(void)
>  {
> -    xc_physinfo_t physinfo = { 0 };
> +    xc_physinfo_t physinfo;
>      int ret;
> 
>      ret = xc_physinfo(xc_handle, &physinfo);
> --
> 2.11.0
> 

Reviewed-by: Wei Chen <Wei.Chen@arm.com>

Patchew 2.1-devel-0870f84

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