xen/arm: Introduce gpaddr_bits field to struct xen_domctl_getdomaininfo

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 (p2m_ipa_bits variable on Arm, the x86 equivalent
is hap_paddr_bits).

Add an explicit padding after "gpaddr_bits" field and also
(while at it) after "domain" field.

Also make sure that full structure is cleared in all cases by
moving the clearing into getdomaininfo(). Currently it is only
cleared by the sysctl caller (and only once).

Please note, we do not need to bump XEN_DOMCTL_INTERFACE_VERSION
as a bump has already occurred in this release cycle. But we do
need to bump XEN_SYSCTL_INTERFACE_VERSION as the structure is
re-used in a sysctl.

Suggested-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Ian Jackson <iwj@xenproject.org>
[hypervisor parts]
Reviewed-by: Jan Beulich <jbeulich@suse.com>

tools/include/libxl.h

@@ -885,6 +885,14 @@ typedef struct libxl__ctx libxl_ctx;
  */
 #define LIBXL_HAVE_DOMINFO_NEVER_STOP 1
 
+/*
+ * LIBXL_HAVE_DOMINFO_GPADDR_BITS
+ *
+ * If this is defined, libxl_dominfo will contain an uint8 field called
+ * gpaddr_bits, containing the guest physical address space size.
+ */
+#define LIBXL_HAVE_DOMINFO_GPADDR_BITS 1
+
 /*
  * LIBXL_HAVE_QXL
  *

tools/include/xenctrl.h

@@ -462,6 +462,7 @@ typedef struct xc_dominfo {
     unsigned int  max_vcpu_id;
     xen_domain_handle_t handle;
     unsigned int  cpupool;
+    uint8_t       gpaddr_bits;
     struct xen_arch_domainconfig arch_config;
 } xc_dominfo_t;
 

tools/libs/ctrl/xc_domain.c

@@ -396,6 +396,7 @@ int xc_domain_getinfo(xc_interface *xch,
         info->nr_online_vcpus = domctl.u.getdomaininfo.nr_online_vcpus;
         info->max_vcpu_id = domctl.u.getdomaininfo.max_vcpu_id;
         info->cpupool = domctl.u.getdomaininfo.cpupool;
+        info->gpaddr_bits = domctl.u.getdomaininfo.gpaddr_bits;
         info->arch_config = domctl.u.getdomaininfo.arch_config;
 
         memcpy(info->handle, domctl.u.getdomaininfo.handle,

tools/libs/light/libxl_domain.c

@@ -306,6 +306,7 @@ void libxl__xcinfo2xlinfo(libxl_ctx *ctx,
     xlinfo->vcpu_max_id = xcinfo->max_vcpu_id;
     xlinfo->vcpu_online = xcinfo->nr_online_vcpus;
     xlinfo->cpupool = xcinfo->cpupool;
+    xlinfo->gpaddr_bits = xcinfo->gpaddr_bits;
     xlinfo->domain_type = (xcinfo->flags & XEN_DOMINF_hvm_guest) ?
         LIBXL_DOMAIN_TYPE_HVM : LIBXL_DOMAIN_TYPE_PV;
 }

tools/libs/light/libxl_types.idl

@@ -357,6 +357,7 @@ libxl_dominfo = Struct("dominfo",[
     ("vcpu_max_id", uint32),
     ("vcpu_online", uint32),
     ("cpupool",     uint32),
+    ("gpaddr_bits", uint8),
     ("domain_type", libxl_domain_type),
     ], dir=DIR_OUT)
 

xen/arch/arm/domctl.c

@@ -20,6 +20,8 @@ void arch_get_domain_info(const struct domain *d,
 {
     /* All ARM domains use hardware assisted paging. */
     info->flags |= XEN_DOMINF_hap;
+
+    info->gpaddr_bits = p2m_ipa_bits;
 }
 
 static int handle_vuart_init(struct domain *d, 

xen/arch/x86/domctl.c

@@ -151,6 +151,7 @@ void arch_get_domain_info(const struct domain *d,
         info->flags |= XEN_DOMINF_hap;
 
     info->arch_config.emulation_flags = d->arch.emulation_flags;
+    info->gpaddr_bits = hap_paddr_bits;
 }
 
 static int do_vmtrace_op(struct domain *d, struct xen_domctl_vmtrace_op *op,

xen/common/domctl.c

@@ -69,10 +69,10 @@ void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info)
     int flags = XEN_DOMINF_blocked;
     struct vcpu_runstate_info runstate;
 
+    memset(info, 0, sizeof(*info));
+
     info->domain = d->domain_id;
     info->max_vcpu_id = XEN_INVALID_MAX_VCPU_ID;
-    info->nr_online_vcpus = 0;
-    info->ssidref = 0;
 
     /*
      * - domain is marked as blocked only if all its vcpus are blocked

xen/common/sysctl.c

@@ -76,7 +76,7 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
     case XEN_SYSCTL_getdomaininfolist:
     { 
         struct domain *d;
-        struct xen_domctl_getdomaininfo info = { 0 };
+        struct xen_domctl_getdomaininfo info;
         u32 num_domains = 0;
 
         rcu_read_lock(&domlist_read_lock);

xen/include/public/domctl.h

@@ -107,6 +107,7 @@ struct xen_domctl_createdomain {
 struct xen_domctl_getdomaininfo {
     /* OUT variables. */
     domid_t  domain;              /* Also echoed in domctl.domain */
+    uint16_t pad1;
  /* Domain is scheduled to die. */
 #define _XEN_DOMINF_dying     0
 #define XEN_DOMINF_dying      (1U<<_XEN_DOMINF_dying)
@@ -151,6 +152,8 @@ struct xen_domctl_getdomaininfo {
     uint32_t ssidref;
     xen_domain_handle_t handle;
     uint32_t cpupool;
+    uint8_t gpaddr_bits; /* Guest physical address space size. */
+    uint8_t pad2[7];
     struct xen_arch_domainconfig arch_config;
 };
 typedef struct xen_domctl_getdomaininfo xen_domctl_getdomaininfo_t;

xen/include/public/sysctl.h

@@ -35,7 +35,7 @@
 #include "domctl.h"
 #include "physdev.h"
 
-#define XEN_SYSCTL_INTERFACE_VERSION 0x00000013
+#define XEN_SYSCTL_INTERFACE_VERSION 0x00000014
 
 /*
  * Read console content from Xen buffer ring.