[v3] x86/domain: revisit logging in arch_domain_create()

Commit Message

Denis Mukhin April 2, 2025, 9:44 p.m. UTC

From: Denis Mukhin <[e-mail]>

Use %pd in all logs issued from arch_domain_create().

Also, expand error message in arch_domain_create() under
!emulation_flags_ok() case to help debugging.

Signed-off-by: Denis Mukhin <[e-mail]>
---
Changes since v2:
- dropped full stops in the updated log messages
---
 xen/arch/x86/domain.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

Comments

Jan Beulich April 3, 2025, 4:02 p.m. UTC | #1

On 02.04.2025 23:44, [e-mail] wrote:
> From: Denis Mukhin <[e-mail]>
> 
> Use %pd in all logs issued from arch_domain_create().
> 
> Also, expand error message in arch_domain_create() under
> !emulation_flags_ok() case to help debugging.
> 
> Signed-off-by: Denis Mukhin <[e-mail]>

A few nits:

> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -791,13 +791,12 @@ int arch_domain_create(struct domain *d,
>      {
>          if ( !opt_allow_unsafe )
>          {
> -            printk(XENLOG_G_ERR "Xen does not allow DomU creation on this CPU"
> -                   " for security reasons.\n");
> +            printk(XENLOG_G_ERR "%pd: Xen does not allow DomU creation on this CPU"
> +                   " for security reasons\n", d);

If this is touched, I think it would better become

            printk(XENLOG_G_ERR
                   "%pd: Xen does not allow DomU creation on this CPU for security reasons\n"
                   d);

to follow our "don't wrap format strings" principle.

>              return -EPERM;
>          }
>          printk(XENLOG_G_WARNING
> -               "Dom%d may compromise security on this CPU.\n",
> -               d->domain_id);
> +               "%pd: domain may compromise security on this CPU\n", d);

Personally I don't think the word "domain" needs adding here.

> @@ -807,16 +806,19 @@ int arch_domain_create(struct domain *d,
>  
>      if ( emflags & ~XEN_X86_EMU_ALL )
>      {
> -        printk(XENLOG_G_ERR "d%d: Invalid emulation bitmap: %#x\n",
> -               d->domain_id, emflags);
> +        printk(XENLOG_G_ERR "%pd: Invalid emulation bitmap: %#x\n",

Please switch to using a lower case 'i' on "invalid".

> +               d, emflags);
>          return -EINVAL;
>      }
>  
>      if ( !emulation_flags_ok(d, emflags) )
>      {
> -        printk(XENLOG_G_ERR "d%d: Xen does not allow %s domain creation "
> +        printk(XENLOG_G_ERR "%pd: Xen does not allow %s %sdomain creation "
>                 "with the current selection of emulators: %#x\n",

Here wrapping of the format string would also be nice to avoid. That
may call for an attempt to shorten the text a little. Maybe "with
this set of emulators:" would already help some.

Jan

Patch

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 4989600627..4ae1344cf5 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -791,13 +791,12 @@  int arch_domain_create(struct domain *d,
     {
         if ( !opt_allow_unsafe )
         {
-            printk(XENLOG_G_ERR "Xen does not allow DomU creation on this CPU"
-                   " for security reasons.\n");
+            printk(XENLOG_G_ERR "%pd: Xen does not allow DomU creation on this CPU"
+                   " for security reasons\n", d);
             return -EPERM;
         }
         printk(XENLOG_G_WARNING
-               "Dom%d may compromise security on this CPU.\n",
-               d->domain_id);
+               "%pd: domain may compromise security on this CPU\n", d);
     }
 
     emflags = config->arch.emulation_flags;
@@ -807,16 +806,19 @@  int arch_domain_create(struct domain *d,
 
     if ( emflags & ~XEN_X86_EMU_ALL )
     {
-        printk(XENLOG_G_ERR "d%d: Invalid emulation bitmap: %#x\n",
-               d->domain_id, emflags);
+        printk(XENLOG_G_ERR "%pd: Invalid emulation bitmap: %#x\n",
+               d, emflags);
         return -EINVAL;
     }
 
     if ( !emulation_flags_ok(d, emflags) )
     {
-        printk(XENLOG_G_ERR "d%d: Xen does not allow %s domain creation "
+        printk(XENLOG_G_ERR "%pd: Xen does not allow %s %sdomain creation "
                "with the current selection of emulators: %#x\n",
-               d->domain_id, is_hvm_domain(d) ? "HVM" : "PV", emflags);
+               d,
+               is_hvm_domain(d) ? "HVM" : "PV",
+               is_hardware_domain(d) ? "hardware " : "",
+               emflags);
         return -EOPNOTSUPP;
     }
     d->arch.emulation_flags = emflags;