[PATCH V5 1/3] xen/arm: Introduce gpaddr_bits field to struct xen_arch_domainconfig

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

We need to pass info about maximum supported guest physical
address space size to the toolstack on Arm in order to properly
calculate the base and size of the extended region (safe range)
for the guest. The extended region is unused address space which
could be safely used by domain for foreign/grant mappings on Arm.
The extended region itself will be handled by the subsequent
patch.

Currently the same guest physical address space size is used
for all guests.

As we add new field to the structure bump the interface version.

Suggested-by: Julien Grall <jgrall@xxxxxxxxxx>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
Changes RFC -> V2:
   - update patch subject/description
   - replace arch-specific sub-struct with common gpaddr_bits
     field and update code to reflect that

Changes V2 -> V3:
   - make the field uint8_t and add uint8_t pad[7] after
   - remove leading blanks in libxl.h

Changes V3 -> V4:
   - also print gpaddr_bits from output_physinfo()
   - add Michal's R-b

Changes V4 -> V5:
   - update patch subject and description
   - drop Michal's R-b
   - pass gpaddr_bits via createdomain domctl
     (struct xen_arch_domainconfig)
---
 tools/include/libxl.h            | 5 +++++
 tools/libs/light/libxl_arm.c     | 2 ++
 tools/libs/light/libxl_types.idl | 1 +
 xen/arch/arm/domain.c            | 6 ++++++
 xen/include/public/arch-arm.h    | 5 +++++
 xen/include/public/domctl.h      | 2 +-
 6 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/tools/include/libxl.h b/tools/include/libxl.h
index b9ba16d..33b4bfb 100644
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -279,6 +279,11 @@
 #define LIBXL_HAVE_BUILDINFO_ARCH_ARM_TEE 1
 
 /*
+ * libxl_domain_build_info has the gpaddr_bits field.
+ */
+#define LIBXL_HAVE_BUILDINFO_ARCH_ARM_GPADDR_BITS 1
+
+/*
  * LIBXL_HAVE_SOFT_RESET indicates that libxl supports performing
  * 'soft reset' for domains and there is 'soft_reset' shutdown reason
  * in enum libxl_shutdown_reason.
diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
index e3140a6..45e0386 100644
--- a/tools/libs/light/libxl_arm.c
+++ b/tools/libs/light/libxl_arm.c
@@ -123,6 +123,8 @@ int libxl__arch_domain_save_config(libxl__gc *gc,
 
     state->clock_frequency = config->arch.clock_frequency;
 
+    d_config->b_info.arch_arm.gpaddr_bits = config->arch.gpaddr_bits;
+
     return 0;
 }
 
diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
index 3f9fff6..39482db 100644
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -644,6 +644,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
 
     ("arch_arm", Struct(None, [("gic_version", libxl_gic_version),
                                ("vuart", libxl_vuart_type),
+                               ("gpaddr_bits", uint8),
                               ])),
     ("arch_x86", Struct(None, [("msr_relaxed", libxl_defbool),
                               ])),
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 19c756a..dfecc45 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -767,6 +767,12 @@ int arch_domain_create(struct domain *d,
     if ( is_hardware_domain(d) && (rc = domain_vuart_init(d)) )
         goto fail;
 
+    /*
+     * Pass maximum IPA bits to the toolstack, currently the same guest
+     * physical address space size is used for all guests.
+     */
+    config->arch.gpaddr_bits = p2m_ipa_bits;
+
     return 0;
 
 fail:
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index 6b5a5f8..4a01f8b 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -333,6 +333,11 @@ struct xen_arch_domainconfig {
      *
      */
     uint32_t clock_frequency;
+    /*
+     * OUT
+     * Guest physical address space size
+     */
+    uint8_t gpaddr_bits;
 };
 #endif /* __XEN__ || __XEN_TOOLS__ */
 
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 96696e3..f37586e 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -38,7 +38,7 @@
 #include "hvm/save.h"
 #include "memory.h"
 
-#define XEN_DOMCTL_INTERFACE_VERSION 0x00000014
+#define XEN_DOMCTL_INTERFACE_VERSION 0x00000015
 
 /*
  * NB. xen_domctl.domain is an IN/OUT parameter for this operation.
-- 
2.7.4