From: Petr Beneš <w1benny@gmail.com>

Introduce a new altp2m_count parameter to control the maximum number of altp2m
views a domain can use. By default, if altp2m_count is unspecified and altp2m
is enabled, the value is set to 10, reflecting the legacy behavior.

This change is preparatory; it establishes the groundwork for the feature but
does not activate it.

Signed-off-by: Petr Beneš <w1benny@gmail.com>
---
 tools/golang/xenlight/helpers.gen.go | 2 ++
 tools/golang/xenlight/types.gen.go   | 1 +
 tools/include/libxl.h                | 8 ++++++++
 tools/libs/light/libxl_create.c      | 9 +++++++++
 tools/libs/light/libxl_types.idl     | 1 +
 tools/xl/xl_parse.c                  | 4 ++++
 6 files changed, 25 insertions(+)

diff --git a/tools/golang/xenlight/helpers.gen.go b/tools/golang/xenlight/helpers.gen.go
index 78bdb08b15..40c247a0d0 100644
--- a/tools/golang/xenlight/helpers.gen.go
+++ b/tools/golang/xenlight/helpers.gen.go
@@ -1158,6 +1158,7 @@ if err := x.ArchX86.MsrRelaxed.fromC(&xc.arch_x86.msr_relaxed);err != nil {
 return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err)
 }
 x.Altp2M = Altp2MMode(xc.altp2m)
+x.Altp2MCount = uint32(xc.altp2m_count)
 x.VmtraceBufKb = int(xc.vmtrace_buf_kb)
 if err := x.Vpmu.fromC(&xc.vpmu);err != nil {
 return fmt.Errorf("converting field Vpmu: %v", err)
@@ -1674,6 +1675,7 @@ if err := x.ArchX86.MsrRelaxed.toC(&xc.arch_x86.msr_relaxed); err != nil {
 return fmt.Errorf("converting field ArchX86.MsrRelaxed: %v", err)
 }
 xc.altp2m = C.libxl_altp2m_mode(x.Altp2M)
+xc.altp2m_count = C.uint32_t(x.Altp2MCount)
 xc.vmtrace_buf_kb = C.int(x.VmtraceBufKb)
 if err := x.Vpmu.toC(&xc.vpmu); err != nil {
 return fmt.Errorf("converting field Vpmu: %v", err)
diff --git a/tools/golang/xenlight/types.gen.go b/tools/golang/xenlight/types.gen.go
index ccfe18019e..a3ae8ef35a 100644
--- a/tools/golang/xenlight/types.gen.go
+++ b/tools/golang/xenlight/types.gen.go
@@ -602,6 +602,7 @@ ArchX86 struct {
 MsrRelaxed Defbool
 }
 Altp2M Altp2MMode
+Altp2MCount uint32
 VmtraceBufKb int
 Vpmu Defbool
 }
diff --git a/tools/include/libxl.h b/tools/include/libxl.h
index 62cb07dea6..1f149a8015 100644
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -1239,6 +1239,14 @@ typedef struct libxl__ctx libxl_ctx;
  */
 #define LIBXL_HAVE_ALTP2M 1

+/*
+ * LIBXL_HAVE_ALTP2M_COUNT
+ * If this is defined, then libxl supports setting the maximum number of
+ * alternate p2m tables.
+ */
+#define LIBXL_HAVE_ALTP2M_COUNT 1
+#define LIBXL_ALTP2M_COUNT_DEFAULT (~(uint32_t)0)
+
 /*
  * LIBXL_HAVE_REMUS
  * If this is defined, then libxl supports remus.
diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index 41252ec553..236b8c1965 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -483,6 +483,15 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         return -ERROR_INVAL;
     }

+    if (b_info->altp2m_count == LIBXL_ALTP2M_COUNT_DEFAULT) {
+        if ((libxl_defbool_val(b_info->u.hvm.altp2m) ||
+            b_info->altp2m != LIBXL_ALTP2M_MODE_DISABLED))
+            /* Reflect the default legacy count */
+            b_info->altp2m_count = 10;
+        else
+            b_info->altp2m_count = 0;
+    }
+
     /* Assume that providing a bootloader user implies enabling restrict. */
     libxl_defbool_setdefault(&b_info->bootloader_restrict,
                              !!b_info->bootloader_user);
diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
index 79e9c656cc..eb306fedf5 100644
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -728,6 +728,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
     # Alternate p2m is not bound to any architecture or guest type, as it is
     # supported by x86 HVM and ARM support is planned.
     ("altp2m", libxl_altp2m_mode),
+    ("altp2m_count", uint32, {'init_val': 'LIBXL_ALTP2M_COUNT_DEFAULT'}),

     # Size of preallocated vmtrace trace buffers (in KBYTES).
     # Use zero value to disable this feature.
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index c504ab3711..048ab6be0d 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -2063,6 +2063,10 @@ void parse_config_data(const char *config_source,
         }
     }

+    if (!xlu_cfg_get_long(config, "altp2m_count", &l, 1)) {
+        b_info->altp2m_count = l;
+    }
+
     if (!xlu_cfg_get_long(config, "vmtrace_buf_kb", &l, 1) && l) {
         b_info->vmtrace_buf_kb = l;
     }
--
2.34.1