Re: [Xen-devel] [PATCH v6 04/12] xen: add new domctl hypercall to set grant table resource limits

[Daniel De Graaf]

On 09/13/2017 11:46 AM, Juergen Gross wrote:

Add a domctl hypercall to set the domain's resource limits regarding
grant tables. It is accepted only as long as neither
gnttab_setup_table() has been called for the domain, nor the domain
has started to run.

Signed-off-by: Juergen Gross 


Acked-by: Daniel De Graaf 

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[Xen-devel] [PATCH v6 04/12] xen: add new domctl hypercall to set grant table resource limits

[Juergen Gross]

Add a domctl hypercall to set the domain's resource limits regarding
grant tables. It is accepted only as long as neither
gnttab_setup_table() has been called for the domain, nor the domain
has started to run.

Signed-off-by: Juergen Gross 
---
V6:
- moved earlier in series to support set_gnttab_limits being
  mandatory for domain creation

V5:
- add set_gnttab_limits to create_domain_common in xen.if
  (Daniel De Graaf)

V3:
- rename *gnttbl* to *gnttab* (Paul Durrant)
---
 tools/flask/policy/modules/dom0.te  |  2 +-
 tools/flask/policy/modules/xen.if   |  2 +-
 xen/common/domctl.c |  6 ++
 xen/common/grant_table.c| 19 +++
 xen/include/public/domctl.h | 11 +++
 xen/include/xen/grant_table.h   |  2 ++
 xen/xsm/flask/hooks.c   |  3 +++
 xen/xsm/flask/policy/access_vectors |  2 ++
 8 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/tools/flask/policy/modules/dom0.te 
b/tools/flask/policy/modules/dom0.te
index 338caaf41e..1643b400f0 100644
--- a/tools/flask/policy/modules/dom0.te
+++ b/tools/flask/policy/modules/dom0.te
@@ -39,7 +39,7 @@ allow dom0_t dom0_t:domain {
 };
 allow dom0_t dom0_t:domain2 {
set_cpuid gettsc settsc setscheduler set_max_evtchn set_vnumainfo
-   get_vnumainfo psr_cmt_op psr_cat_op
+   get_vnumainfo psr_cmt_op psr_cat_op set_gnttab_limits
 };
 allow dom0_t dom0_t:resource { add remove };
 
diff --git a/tools/flask/policy/modules/xen.if 
b/tools/flask/policy/modules/xen.if
index 912640002e..55437496f6 100644
--- a/tools/flask/policy/modules/xen.if
+++ b/tools/flask/policy/modules/xen.if
@@ -52,7 +52,7 @@ define(`create_domain_common', `
settime setdomainhandle getvcpucontext set_misc_info };
allow $1 $2:domain2 { set_cpuid settsc setscheduler setclaim
set_max_evtchn set_vnumainfo get_vnumainfo cacheflush
-   psr_cmt_op psr_cat_op soft_reset };
+   psr_cmt_op psr_cat_op soft_reset set_gnttab_limits };
allow $1 $2:security check_context;
allow $1 $2:shadow enable;
allow $1 $2:mmu { map_read map_write adjust memorymap physmap pinpage 
mmuext_op updatemp };
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 42658e5744..58381f8fe9 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -14,6 +14,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -1149,6 +1150,11 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
 copyback = 1;
 break;
 
+case XEN_DOMCTL_set_gnttab_limits:
+ret = grant_table_set_limits(d, op->u.set_gnttab_limits.grant_frames,
+ op->u.set_gnttab_limits.maptrack_frames);
+break;
+
 default:
 ret = arch_do_domctl(op, d, u_domctl);
 break;
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 5b296f9134..28ee050bad 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -3640,6 +3640,25 @@ void grant_table_init_vcpu(struct vcpu *v)
 v->maptrack_tail = MAPTRACK_TAIL;
 }
 
+int grant_table_set_limits(struct domain *d, unsigned int grant_frames,
+   unsigned int maptrack_frames)
+{
+struct grant_table *gt = d->grant_table;
+int ret = -EBUSY;
+
+if ( !gt )
+return -ENOENT;
+
+grant_write_lock(gt);
+
+ret = 0;
+/* Set limits, alloc needed arrays. */
+
+grant_write_unlock(gt);
+
+return ret;
+}
+
 #ifdef CONFIG_HAS_MEM_SHARING
 int mem_sharing_gref_to_gfn(struct grant_table *gt, grant_ref_t ref,
 gfn_t *gfn, uint16_t *status)
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 50ff58f5b9..685c6ebc15 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1163,6 +1163,15 @@ struct xen_domctl_psr_cat_op {
 typedef struct xen_domctl_psr_cat_op xen_domctl_psr_cat_op_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_psr_cat_op_t);
 
+struct xen_domctl_set_gnttab_limits {
+uint32_t grant_frames; /* IN: if 0, dont change */
+uint32_t maptrack_frames;  /* IN: if 0, dont change */
+};
+#if 0
+typedef struct xen_domctl_set_gnttab_limits xen_domctl_set_gnttab_limits_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_set_gnttab_limits_t);
+#endif
+
 struct xen_domctl {
 uint32_t cmd;
 #define XEN_DOMCTL_createdomain   1
@@ -1240,6 +1249,7 @@ struct xen_domctl {
 #define XEN_DOMCTL_monitor_op77
 #define XEN_DOMCTL_psr_cat_op78
 #define XEN_DOMCTL_soft_reset79
+#define XEN_DOMCTL_set_gnttab_limits 80
 #define XEN_DOMCTL_gdbsx_guestmemio1000
 #define XEN_DOMCTL_gdbsx_pausevcpu 1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu   1002
@@ -1302,6 +1312,7 @@ struct xen_domctl {
 struct xen_domctl_psr_cmt_op