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[Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor

Wei Liu posted 9 patches 6 years, 1 month ago
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[Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor
Posted by Wei Liu 6 years, 1 month ago 
Signed-off-by: Wei Liu <liuwe@microsoft.com>
---
 xen/arch/x86/guest/hypervisor.c        | 5 +++++
 xen/arch/x86/setup.c                   | 6 +++++-
 xen/include/asm-x86/guest/hypervisor.h | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c
index 30453b6a7a..8161b26c5a 100644
--- a/xen/arch/x86/guest/hypervisor.c
+++ b/xen/arch/x86/guest/hypervisor.c
@@ -43,6 +43,11 @@ bool hypervisor_probe(void)
     return !!hops;
 }
 
+const char *hypervisor_name(void)
+{
+    return hops->name;
+}
+
 void hypervisor_setup(void)
 {
     if ( hops && hops->setup )
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 0ee11b15a6..cf5a7b8e1e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -689,6 +689,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     int i, j, e820_warn = 0, bytes = 0;
     bool acpi_boot_table_init_done = false, relocated = false;
     int ret;
+    bool running_on_hypervisor;
     struct ns16550_defaults ns16550 = {
         .data_bits = 8,
         .parity    = 'n',
@@ -763,7 +764,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
      * allocing any xenheap structures wanted in lower memory. */
     kexec_early_calculations();
 
-    hypervisor_probe();
+    running_on_hypervisor = hypervisor_probe();
 
     parse_video_info();
 
@@ -789,6 +790,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     printk("Xen image load base address: %#lx\n", xen_phys_start);
 
+    if ( running_on_hypervisor )
+        printk("Running on %s\n", hypervisor_name());
+
 #ifdef CONFIG_VIDEO
     printk("Video information:\n");
 
diff --git a/xen/include/asm-x86/guest/hypervisor.h b/xen/include/asm-x86/guest/hypervisor.h
index 38344e2e89..a7d75bf9cf 100644
--- a/xen/include/asm-x86/guest/hypervisor.h
+++ b/xen/include/asm-x86/guest/hypervisor.h
@@ -36,6 +36,7 @@ bool hypervisor_probe(void);
 void hypervisor_setup(void);
 void hypervisor_ap_setup(void);
 void hypervisor_resume(void);
+const char *hypervisor_name(void);
 
 #else
 
@@ -45,6 +46,7 @@ static inline bool hypervisor_probe(void) { return false; }
 static inline void hypervisor_setup(void) {}
 static inline void hypervisor_ap_setup(void) {}
 static inline void hypervisor_resume(void) {}
+static inline char *hypervisor_name(void) { return NULL; }
 
 #endif  /* CONFIG_GUEST */
 
-- 
2.20.1


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Re: [Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor
Posted by Roger Pau Monné 6 years ago 
On Mon, Sep 30, 2019 at 04:00:42PM +0100, Wei Liu wrote:
> Signed-off-by: Wei Liu <liuwe@microsoft.com>
> ---
>  xen/arch/x86/guest/hypervisor.c        | 5 +++++
>  xen/arch/x86/setup.c                   | 6 +++++-
>  xen/include/asm-x86/guest/hypervisor.h | 2 ++
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c
> index 30453b6a7a..8161b26c5a 100644
> --- a/xen/arch/x86/guest/hypervisor.c
> +++ b/xen/arch/x86/guest/hypervisor.c
> @@ -43,6 +43,11 @@ bool hypervisor_probe(void)
>      return !!hops;
>  }
>  
> +const char *hypervisor_name(void)
> +{

I would maybe add ASSERT(hops);

> +    return hops->name;
> +}
> +
>  void hypervisor_setup(void)
>  {
>      if ( hops && hops->setup )
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index 0ee11b15a6..cf5a7b8e1e 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -689,6 +689,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
>      int i, j, e820_warn = 0, bytes = 0;
>      bool acpi_boot_table_init_done = false, relocated = false;
>      int ret;
> +    bool running_on_hypervisor;
>      struct ns16550_defaults ns16550 = {
>          .data_bits = 8,
>          .parity    = 'n',
> @@ -763,7 +764,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
>       * allocing any xenheap structures wanted in lower memory. */
>      kexec_early_calculations();
>  
> -    hypervisor_probe();
> +    running_on_hypervisor = hypervisor_probe();
>  
>      parse_video_info();
>  
> @@ -789,6 +790,9 @@ void __init noreturn __start_xen(unsigned long mbi_p)
>  
>      printk("Xen image load base address: %#lx\n", xen_phys_start);
>  
> +    if ( running_on_hypervisor )
> +        printk("Running on %s\n", hypervisor_name());
> +
>  #ifdef CONFIG_VIDEO
>      printk("Video information:\n");
>  
> diff --git a/xen/include/asm-x86/guest/hypervisor.h b/xen/include/asm-x86/guest/hypervisor.h
> index 38344e2e89..a7d75bf9cf 100644
> --- a/xen/include/asm-x86/guest/hypervisor.h
> +++ b/xen/include/asm-x86/guest/hypervisor.h
> @@ -36,6 +36,7 @@ bool hypervisor_probe(void);
>  void hypervisor_setup(void);
>  void hypervisor_ap_setup(void);
>  void hypervisor_resume(void);
> +const char *hypervisor_name(void);
>  
>  #else
>  
> @@ -45,6 +46,7 @@ static inline bool hypervisor_probe(void) { return false; }
>  static inline void hypervisor_setup(void) {}
>  static inline void hypervisor_ap_setup(void) {}
>  static inline void hypervisor_resume(void) {}
> +static inline char *hypervisor_name(void) { return NULL; }

I think you want an ASSERT_UNREACHABLE here, since hypervisor_name
shouldn't be called unless Xen has detected that's running as a guest,
which can only happen if CONFIG_GUEST is selected.

Thanks, Roger.

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Re: [Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor
Posted by Wei Liu 6 years ago 
On Mon, Oct 21, 2019 at 12:00:38PM +0200, Roger Pau Monné wrote:
> On Mon, Sep 30, 2019 at 04:00:42PM +0100, Wei Liu wrote:
> > Signed-off-by: Wei Liu <liuwe@microsoft.com>
> > ---
> >  xen/arch/x86/guest/hypervisor.c        | 5 +++++
> >  xen/arch/x86/setup.c                   | 6 +++++-
> >  xen/include/asm-x86/guest/hypervisor.h | 2 ++
> >  3 files changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c
> > index 30453b6a7a..8161b26c5a 100644
> > --- a/xen/arch/x86/guest/hypervisor.c
> > +++ b/xen/arch/x86/guest/hypervisor.c
> > @@ -43,6 +43,11 @@ bool hypervisor_probe(void)
> >      return !!hops;
> >  }
> >  
> > +const char *hypervisor_name(void)
> > +{
> 
> I would maybe add ASSERT(hops);
> 
> > +    return hops->name;
> > +}
> > +
[...]
> > diff --git a/xen/include/asm-x86/guest/hypervisor.h b/xen/include/asm-x86/guest/hypervisor.h
> > index 38344e2e89..a7d75bf9cf 100644
> > --- a/xen/include/asm-x86/guest/hypervisor.h
> > +++ b/xen/include/asm-x86/guest/hypervisor.h
> > @@ -36,6 +36,7 @@ bool hypervisor_probe(void);
> >  void hypervisor_setup(void);
> >  void hypervisor_ap_setup(void);
> >  void hypervisor_resume(void);
> > +const char *hypervisor_name(void);
> >  
> >  #else
> >  
> > @@ -45,6 +46,7 @@ static inline bool hypervisor_probe(void) { return false; }
> >  static inline void hypervisor_setup(void) {}
> >  static inline void hypervisor_ap_setup(void) {}
> >  static inline void hypervisor_resume(void) {}
> > +static inline char *hypervisor_name(void) { return NULL; }
> 
> I think you want an ASSERT_UNREACHABLE here, since hypervisor_name
> shouldn't be called unless Xen has detected that's running as a guest,
> which can only happen if CONFIG_GUEST is selected.

Ack to both comments.

Wei.

> 
> Thanks, Roger.

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Re: [Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor
Posted by Jan Beulich 6 years ago 
On 21.10.2019 12:00, Roger Pau Monné wrote:
> On Mon, Sep 30, 2019 at 04:00:42PM +0100, Wei Liu wrote:
>> --- a/xen/include/asm-x86/guest/hypervisor.h
>> +++ b/xen/include/asm-x86/guest/hypervisor.h
>> @@ -36,6 +36,7 @@ bool hypervisor_probe(void);
>>  void hypervisor_setup(void);
>>  void hypervisor_ap_setup(void);
>>  void hypervisor_resume(void);
>> +const char *hypervisor_name(void);
>>  
>>  #else
>>  
>> @@ -45,6 +46,7 @@ static inline bool hypervisor_probe(void) { return false; }
>>  static inline void hypervisor_setup(void) {}
>>  static inline void hypervisor_ap_setup(void) {}
>>  static inline void hypervisor_resume(void) {}
>> +static inline char *hypervisor_name(void) { return NULL; }
> 
> I think you want an ASSERT_UNREACHABLE here, since hypervisor_name
> shouldn't be called unless Xen has detected that's running as a guest,
> which can only happen if CONFIG_GUEST is selected.

And please bring prototype and stub in sync return-type-wise.

Jan

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Re: [Xen-devel] [PATCH for-next v2 8/9] x86: be more verbose when running on a hypervisor
Posted by Wei Liu 6 years ago 
On Wed, Oct 23, 2019 at 03:22:24PM +0200, Jan Beulich wrote:
> On 21.10.2019 12:00, Roger Pau Monné wrote:
> > On Mon, Sep 30, 2019 at 04:00:42PM +0100, Wei Liu wrote:
> >> --- a/xen/include/asm-x86/guest/hypervisor.h
> >> +++ b/xen/include/asm-x86/guest/hypervisor.h
> >> @@ -36,6 +36,7 @@ bool hypervisor_probe(void);
> >>  void hypervisor_setup(void);
> >>  void hypervisor_ap_setup(void);
> >>  void hypervisor_resume(void);
> >> +const char *hypervisor_name(void);
> >>  
> >>  #else
> >>  
> >> @@ -45,6 +46,7 @@ static inline bool hypervisor_probe(void) { return false; }
> >>  static inline void hypervisor_setup(void) {}
> >>  static inline void hypervisor_ap_setup(void) {}
> >>  static inline void hypervisor_resume(void) {}
> >> +static inline char *hypervisor_name(void) { return NULL; }
> > 
> > I think you want an ASSERT_UNREACHABLE here, since hypervisor_name
> > shouldn't be called unless Xen has detected that's running as a guest,
> > which can only happen if CONFIG_GUEST is selected.
> 
> And please bring prototype and stub in sync return-type-wise.

Missed this comment.

I will handle this if I haven't already.

Wei.

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