Re: [PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-10-13 Thread Jan Beulich 
On 05.10.2020 12:39, Andrew Cooper wrote:
> On 24/09/2020 14:10, Paul Durrant wrote:
>> +static int load_shared_info(struct domain *d, struct domain_context *c)
>> +{
>> +struct domain_shared_info_context ctxt;
>> +size_t hdr_size = offsetof(typeof(ctxt), buffer);
>> +unsigned int i;
>> +int rc;
>> +
>> +rc = DOMAIN_LOAD_BEGIN(SHARED_INFO, c, &i);
>> +if ( rc )
>> +return rc;
>> +
>> +if ( i ) /* expect only a single instance */
>> +return -ENXIO;
>> +
>> +rc = domain_load_data(c, &ctxt, hdr_size);
>> +if ( rc )
>> +return rc;
>> +
>> +if ( ctxt.buffer_size > sizeof(shared_info_t) ||
>> + (ctxt.flags & ~DOMAIN_SAVE_32BIT_SHINFO) )
>> +return -EINVAL;
>> +
>> +if ( ctxt.flags & DOMAIN_SAVE_32BIT_SHINFO )
>> +{
>> +#ifdef CONFIG_COMPAT
>> +has_32bit_shinfo(d) = true;
> 
> d->arch.has_32bit_shinfo

But this is common code, i.e. using d->arch directly is a layering
violation. I know your dislike of lvalues disguised by function-
like macros, but what do you do?

Jan

RE: [PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-10-07 Thread Paul Durrant 
> -Original Message-
> From: Andrew Cooper 
> Sent: 05 October 2020 11:40
> To: Paul Durrant ; xen-devel@lists.xenproject.org
> Cc: Paul Durrant ; Ian Jackson 
> ; Wei Liu ;
> George Dunlap ; Jan Beulich ; 
> Julien Grall
> ; Stefano Stabellini 
> Subject: Re: [PATCH v9 6/8] common/domain: add a domain context record for 
> shared_info...
> 
> On 24/09/2020 14:10, Paul Durrant wrote:
> > diff --git a/tools/misc/xen-domctx.c b/tools/misc/xen-domctx.c
> > index 243325dfce..6ead7ea89d 100644
> > --- a/tools/misc/xen-domctx.c
> > +++ b/tools/misc/xen-domctx.c
> > @@ -31,6 +31,7 @@
> >  #include 
> >
> >  #include 
> > +#include 
> >  #include 
> >  #include 
> >  #include 
> > @@ -61,6 +62,82 @@ static void dump_header(void)
> >
> >  }
> >
> > +static void print_binary(const char *prefix, const void *val, size_t size,
> > + const char *suffix)
> > +{
> > +printf("%s", prefix);
> > +
> > +while ( size-- )
> > +{
> > +uint8_t octet = *(const uint8_t *)val++;
> > +unsigned int i;
> > +
> > +for ( i = 0; i < 8; i++ )
> > +{
> > +printf("%u", octet & 1);
> > +octet >>= 1;
> > +}
> > +}
> > +
> > +printf("%s", suffix);
> > +}
> > +
> > +static void dump_shared_info(void)
> > +{
> > +DOMAIN_SAVE_TYPE(SHARED_INFO) *s;
> > +bool has_32bit_shinfo;
> > +shared_info_any_t *info;
> > +unsigned int i, n;
> > +
> > +GET_PTR(s);
> > +has_32bit_shinfo = s->flags & DOMAIN_SAVE_32BIT_SHINFO;
> > +
> > +printf("SHARED_INFO: has_32bit_shinfo: %s buffer_size: %u\n",
> > +   has_32bit_shinfo ? "true" : "false", s->buffer_size);
> > +
> > +info = (shared_info_any_t *)s->buffer;
> > +
> > +#define GET_FIELD_PTR(_f)\
> > +(has_32bit_shinfo ?  \
> > + (const void *)&(info->x32._f) : \
> > + (const void *)&(info->x64._f))
> > +#define GET_FIELD_SIZE(_f) \
> > +(has_32bit_shinfo ? sizeof(info->x32._f) : sizeof(info->x64._f))
> > +#define GET_FIELD(_f) \
> > +(has_32bit_shinfo ? info->x32._f : info->x64._f)
> > +
> > +n = has_32bit_shinfo ?
> > +ARRAY_SIZE(info->x32.evtchn_pending) :
> > +ARRAY_SIZE(info->x64.evtchn_pending);
> > +
> > +for ( i = 0; i < n; i++ )
> > +{
> > +const char *prefix = !i ?
> > +" evtchn_pending: " :
> > +" ";
> > +
> > +print_binary(prefix, GET_FIELD_PTR(evtchn_pending[0]),
> > + GET_FIELD_SIZE(evtchn_pending[0]), "\n");
> > +}
> > +
> > +for ( i = 0; i < n; i++ )
> > +{
> > +const char *prefix = !i ?
> > +"evtchn_mask: " :
> > +" ";
> > +
> > +print_binary(prefix, GET_FIELD_PTR(evtchn_mask[0]),
> > + GET_FIELD_SIZE(evtchn_mask[0]), "\n");
> > +}
> 
> What about domains using FIFO?  This is meaningless for them.
> 

Indeed, but this is essentially a debug tool so I'd rather it just dumped 
everything that might be useful.

> > +
> > +printf(" wc: version: %u sec: %u nsec: %u\n",
> > +   GET_FIELD(wc_version), GET_FIELD(wc_sec), GET_FIELD(wc_nsec));
> 
> wc_sec_hi is also a rather critical field in this calculation.
> 

Ok.

> > +
> > +#undef GET_FIELD
> > +#undef GET_FIELD_SIZE
> > +#undef GET_FIELD_PTR
> > +}
> > +
> >  static void dump_end(void)
> >  {
> >  DOMAIN_SAVE_TYPE(END) *e;
> > @@ -173,6 +250,7 @@ int main(int argc, char **argv)
> >  switch (desc->typecode)
> >  {
> >  case DOMAIN_SAVE_CODE(HEADER): dump_header(); break;
> > +case DOMAIN_SAVE_CODE(SHARED_INFO): dump_shared_info(); break;
> >  case DOMAIN_SAVE_CODE(END): dump_end(); break;
> >  default:
> >  printf("Unknown type %u: skipping\n", desc->typecode);
> > diff --git a/xen/common/domain.c b/xen/common/domain.c
> > index 8cfa2e0b6b..6709f9c79e 100644
> > --- a/xen/co

Re: [PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-10-05 Thread Andrew Cooper 
On 24/09/2020 14:10, Paul Durrant wrote:
> diff --git a/tools/misc/xen-domctx.c b/tools/misc/xen-domctx.c
> index 243325dfce..6ead7ea89d 100644
> --- a/tools/misc/xen-domctx.c
> +++ b/tools/misc/xen-domctx.c
> @@ -31,6 +31,7 @@
>  #include 
>  
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -61,6 +62,82 @@ static void dump_header(void)
>  
>  }
>  
> +static void print_binary(const char *prefix, const void *val, size_t size,
> + const char *suffix)
> +{
> +printf("%s", prefix);
> +
> +while ( size-- )
> +{
> +uint8_t octet = *(const uint8_t *)val++;
> +unsigned int i;
> +
> +for ( i = 0; i < 8; i++ )
> +{
> +printf("%u", octet & 1);
> +octet >>= 1;
> +}
> +}
> +
> +printf("%s", suffix);
> +}
> +
> +static void dump_shared_info(void)
> +{
> +DOMAIN_SAVE_TYPE(SHARED_INFO) *s;
> +bool has_32bit_shinfo;
> +shared_info_any_t *info;
> +unsigned int i, n;
> +
> +GET_PTR(s);
> +has_32bit_shinfo = s->flags & DOMAIN_SAVE_32BIT_SHINFO;
> +
> +printf("SHARED_INFO: has_32bit_shinfo: %s buffer_size: %u\n",
> +   has_32bit_shinfo ? "true" : "false", s->buffer_size);
> +
> +info = (shared_info_any_t *)s->buffer;
> +
> +#define GET_FIELD_PTR(_f)\
> +(has_32bit_shinfo ?  \
> + (const void *)&(info->x32._f) : \
> + (const void *)&(info->x64._f))
> +#define GET_FIELD_SIZE(_f) \
> +(has_32bit_shinfo ? sizeof(info->x32._f) : sizeof(info->x64._f))
> +#define GET_FIELD(_f) \
> +(has_32bit_shinfo ? info->x32._f : info->x64._f)
> +
> +n = has_32bit_shinfo ?
> +ARRAY_SIZE(info->x32.evtchn_pending) :
> +ARRAY_SIZE(info->x64.evtchn_pending);
> +
> +for ( i = 0; i < n; i++ )
> +{
> +const char *prefix = !i ?
> +" evtchn_pending: " :
> +" ";
> +
> +print_binary(prefix, GET_FIELD_PTR(evtchn_pending[0]),
> + GET_FIELD_SIZE(evtchn_pending[0]), "\n");
> +}
> +
> +for ( i = 0; i < n; i++ )
> +{
> +const char *prefix = !i ?
> +"evtchn_mask: " :
> +" ";
> +
> +print_binary(prefix, GET_FIELD_PTR(evtchn_mask[0]),
> + GET_FIELD_SIZE(evtchn_mask[0]), "\n");
> +}

What about domains using FIFO?  This is meaningless for them.

> +
> +printf(" wc: version: %u sec: %u nsec: %u\n",
> +   GET_FIELD(wc_version), GET_FIELD(wc_sec), GET_FIELD(wc_nsec));

wc_sec_hi is also a rather critical field in this calculation.

> +
> +#undef GET_FIELD
> +#undef GET_FIELD_SIZE
> +#undef GET_FIELD_PTR
> +}
> +
>  static void dump_end(void)
>  {
>  DOMAIN_SAVE_TYPE(END) *e;
> @@ -173,6 +250,7 @@ int main(int argc, char **argv)
>  switch (desc->typecode)
>  {
>  case DOMAIN_SAVE_CODE(HEADER): dump_header(); break;
> +case DOMAIN_SAVE_CODE(SHARED_INFO): dump_shared_info(); break;
>  case DOMAIN_SAVE_CODE(END): dump_end(); break;
>  default:
>  printf("Unknown type %u: skipping\n", desc->typecode);
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index 8cfa2e0b6b..6709f9c79e 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -33,6 +33,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -1657,6 +1658,110 @@ int continue_hypercall_on_cpu(
>  return 0;
>  }
>  
> +static int save_shared_info(const struct domain *d, struct domain_context *c,
> +bool dry_run)
> +{
> +struct domain_shared_info_context ctxt = {
> +#ifdef CONFIG_COMPAT
> +.flags = has_32bit_shinfo(d) ? DOMAIN_SAVE_32BIT_SHINFO : 0,
> +.buffer_size = has_32bit_shinfo(d) ?
> +   sizeof(struct compat_shared_info) :
> +   sizeof(struct shared_info),
> +#else
> +.buffer_size = sizeof(struct shared_info),
> +#endif
> +};
> +size_t hdr_size = offsetof(typeof(ctxt), buffer);
> +int rc;
> +
> +rc = DOMAIN_SAVE_BEGIN(SHARED_INFO, c, 0);
> +if ( rc )
> +return rc;
> +
> +rc = domain_save_data(c, &ctxt, hdr_size);
> +if ( rc )
> +return rc;
> +
> +rc = domain_save_data(c, d->shared_info, ctxt.buffer_size);
> +if ( rc )
> +return rc;
> +
> +return domain_save_end(c);
> +}
> +
> +static int load_shared_info(struct domain *d, struct domain_context *c)
> +{
> +struct domain_shared_info_context ctxt;
> +size_t hdr_size = offsetof(typeof(ctxt), buffer);
> +unsigned int i;
> +int rc;
> +
> +rc = DOMAIN_LOAD_BEGIN(SHARED_INFO, c, &i);
> +if ( rc )
> +return rc;
> +
> +if ( i ) /* expect only a single instance */
> +return -ENXIO;
> +
> +rc = domain_load_data(c, &ctxt,

Re: [PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-09-30 Thread Wei Liu 
On Thu, Sep 24, 2020 at 02:10:28PM +0100, Paul Durrant wrote:
> From: Paul Durrant 
> 
> ... and update xen-domctx to dump some information describing the record.
> 
> NOTE: Processing of the content during restore is currently limited to
>   PV domains, and matches processing of the PV-only SHARED_INFO record
>   done by libxc. All content is, however, saved such that restore
>   processing can be modified in future without requiring a new record
>   format.
> 
> Signed-off-by: Paul Durrant 

Acked-by: Wei Liu

Re: [PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-09-25 Thread Jan Beulich 
On 24.09.2020 15:10, Paul Durrant wrote:
> From: Paul Durrant 
> 
> ... and update xen-domctx to dump some information describing the record.
> 
> NOTE: Processing of the content during restore is currently limited to
>   PV domains, and matches processing of the PV-only SHARED_INFO record
>   done by libxc. All content is, however, saved such that restore
>   processing can be modified in future without requiring a new record
>   format.
> 
> Signed-off-by: Paul Durrant 

Reviewed-by: Jan Beulich

[PATCH v9 6/8] common/domain: add a domain context record for shared_info...

2020-09-24 Thread Paul Durrant 
From: Paul Durrant 

... and update xen-domctx to dump some information describing the record.

NOTE: Processing of the content during restore is currently limited to
  PV domains, and matches processing of the PV-only SHARED_INFO record
  done by libxc. All content is, however, saved such that restore
  processing can be modified in future without requiring a new record
  format.

Signed-off-by: Paul Durrant 
---
Cc: Ian Jackson 
Cc: Wei Liu 
Cc: Andrew Cooper 
Cc: George Dunlap 
Cc: Jan Beulich 
Cc: Julien Grall 
Cc: Stefano Stabellini 

v9:
 - Use macros to make the code less verbose
 - Add missing check for allocation failure

v8:
 - Incorporate zero-ing out of shared info fields that would be done in
   processing of SHARED_INFO from older stream versions

v7:
 - Only restore vcpu_info and arch sub-structures for PV domains, to match
   processing of SHARED_INFO in xc_sr_restore_x86_pv.c
 - Use additional option to domain_load_end() to ignore the record for
   HVM domains

v6:
 - Only save compat_shared_info buffer if has_32bit_shinfo is set
 - Validate flags field in load handler

v5:
 - Addressed comments from Julien

v4:
 - Addressed comments from Jan

v3:
 - Actually dump some of the content of shared_info

v2:
 - Drop the header change to define a 'Xen' page size and instead use a
   variable length struct now that the framework makes this is feasible
 - Guard use of 'has_32bit_shinfo' in common code with CONFIG_COMPAT
---
 tools/misc/xen-domctx.c   |  78 
 xen/common/domain.c   | 105 ++
 xen/include/public/save.h |  13 -
 3 files changed, 195 insertions(+), 1 deletion(-)

diff --git a/tools/misc/xen-domctx.c b/tools/misc/xen-domctx.c
index 243325dfce..6ead7ea89d 100644
--- a/tools/misc/xen-domctx.c
+++ b/tools/misc/xen-domctx.c
@@ -31,6 +31,7 @@
 #include 
 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -61,6 +62,82 @@ static void dump_header(void)
 
 }
 
+static void print_binary(const char *prefix, const void *val, size_t size,
+ const char *suffix)
+{
+printf("%s", prefix);
+
+while ( size-- )
+{
+uint8_t octet = *(const uint8_t *)val++;
+unsigned int i;
+
+for ( i = 0; i < 8; i++ )
+{
+printf("%u", octet & 1);
+octet >>= 1;
+}
+}
+
+printf("%s", suffix);
+}
+
+static void dump_shared_info(void)
+{
+DOMAIN_SAVE_TYPE(SHARED_INFO) *s;
+bool has_32bit_shinfo;
+shared_info_any_t *info;
+unsigned int i, n;
+
+GET_PTR(s);
+has_32bit_shinfo = s->flags & DOMAIN_SAVE_32BIT_SHINFO;
+
+printf("SHARED_INFO: has_32bit_shinfo: %s buffer_size: %u\n",
+   has_32bit_shinfo ? "true" : "false", s->buffer_size);
+
+info = (shared_info_any_t *)s->buffer;
+
+#define GET_FIELD_PTR(_f)\
+(has_32bit_shinfo ?  \
+ (const void *)&(info->x32._f) : \
+ (const void *)&(info->x64._f))
+#define GET_FIELD_SIZE(_f) \
+(has_32bit_shinfo ? sizeof(info->x32._f) : sizeof(info->x64._f))
+#define GET_FIELD(_f) \
+(has_32bit_shinfo ? info->x32._f : info->x64._f)
+
+n = has_32bit_shinfo ?
+ARRAY_SIZE(info->x32.evtchn_pending) :
+ARRAY_SIZE(info->x64.evtchn_pending);
+
+for ( i = 0; i < n; i++ )
+{
+const char *prefix = !i ?
+" evtchn_pending: " :
+" ";
+
+print_binary(prefix, GET_FIELD_PTR(evtchn_pending[0]),
+ GET_FIELD_SIZE(evtchn_pending[0]), "\n");
+}
+
+for ( i = 0; i < n; i++ )
+{
+const char *prefix = !i ?
+"evtchn_mask: " :
+" ";
+
+print_binary(prefix, GET_FIELD_PTR(evtchn_mask[0]),
+ GET_FIELD_SIZE(evtchn_mask[0]), "\n");
+}
+
+printf(" wc: version: %u sec: %u nsec: %u\n",
+   GET_FIELD(wc_version), GET_FIELD(wc_sec), GET_FIELD(wc_nsec));
+
+#undef GET_FIELD
+#undef GET_FIELD_SIZE
+#undef GET_FIELD_PTR
+}
+
 static void dump_end(void)
 {
 DOMAIN_SAVE_TYPE(END) *e;
@@ -173,6 +250,7 @@ int main(int argc, char **argv)
 switch (desc->typecode)
 {
 case DOMAIN_SAVE_CODE(HEADER): dump_header(); break;
+case DOMAIN_SAVE_CODE(SHARED_INFO): dump_shared_info(); break;
 case DOMAIN_SAVE_CODE(END): dump_end(); break;
 default:
 printf("Unknown type %u: skipping\n", desc->typecode);
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 8cfa2e0b6b..6709f9c79e 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -33,6 +33,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -1657,6 +1658,110 @@ int continue_hypercall_on_cpu(
 return 0;
 }
 
+static int save_shared_info(const struct domain *d, struct domain_context *c,
+