[PATCH v2 6/6] xen/arm: grant table

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Implement XENMAPSPACE_grant_table and grant_table_op.

Introduce an HVM_PARAM to tell the guest where to map the grant table
(HVM_PARAM_GRANT_START_PFN), similarly to what we do with
HVM_PARAM_CONSOLE_PFN and HVM_PARAM_STORE_PFN.
However HVM_PARAM_GRANT_START_PFN is also going to be used by dom0, so
we set the parameter in Xen rather than libxc.
Using HVM_PARAM_GRANT_START_PFN removes the need for a platform pci
device.

Statically set HVM_PARAM_GRANT_START_PFN to 0xb0000000 for now.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
---
 xen/arch/arm/domain.c           |    3 +++
 xen/arch/arm/mm.c               |   29 ++++++++++++++++++++++++++++-
 xen/arch/arm/traps.c            |    1 +
 xen/include/public/hvm/params.h |    4 +++-
 4 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 6e1e08a..7c56cf3 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -345,6 +345,9 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags)
 
         if ( (rc = p2m_alloc_table(d)) != 0 )
             goto fail;
+
+        /* XXX: select this dynamically */
+        d->arch.hvm_domain.params[HVM_PARAM_GRANT_START_PFN] = 0xb0000;
     }
 
     if ( (rc = domain_vgic_init(d)) != 0 )
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 7033023..2f28a18 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -25,6 +25,7 @@
 #include <xen/mm.h>
 #include <xen/preempt.h>
 #include <xen/errno.h>
+#include <xen/grant_table.h>
 #include <xen/guest_access.h>
 #include <asm/page.h>
 #include <asm/current.h>
@@ -477,7 +478,7 @@ static int xenmem_add_to_physmap_once(
     struct domain *d,
     const struct xen_add_to_physmap *xatp)
 {
-    unsigned long mfn = 0;
+    unsigned long mfn = 0, idx = 0;
     int rc;
 
     switch ( xatp->space )
@@ -506,6 +507,32 @@ static int xenmem_add_to_physmap_once(
         rcu_unlock_domain(od);
         break;
     }
+    case XENMAPSPACE_grant_table:
+        spin_lock(&d->grant_table->lock);
+
+        if ( d->grant_table->gt_version == 0 )
+            d->grant_table->gt_version = 1;
+
+        idx = xatp->idx;
+        if ( d->grant_table->gt_version == 2 &&
+                (xatp->idx & XENMAPIDX_grant_table_status) )
+        {
+            idx &= ~XENMAPIDX_grant_table_status;
+            if ( idx < nr_status_frames(d->grant_table) )
+                mfn = virt_to_mfn(d->grant_table->status[idx]);
+        }
+        else
+        {
+            if ( (idx >= nr_grant_frames(d->grant_table)) &&
+                    (idx < max_nr_grant_frames) )
+                gnttab_grow_table(d, idx + 1);
+
+            if ( idx < nr_grant_frames(d->grant_table) )
+                mfn = virt_to_mfn(d->grant_table->shared_raw[idx]);
+        }
+
+        spin_unlock(&d->grant_table->lock);
+        break;
     default:
         return -ENOSYS;
     }
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 3900545..cdbd11f 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -431,6 +431,7 @@ static arm_hypercall_t *arm_hypercall_table[] = {
     HYPERCALL(physdev_op),
     HYPERCALL(sysctl),
     HYPERCALL(hvm_op),
+    HYPERCALL(grant_table_op),
 };
 
 static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code)
diff --git a/xen/include/public/hvm/params.h b/xen/include/public/hvm/params.h
index 55c1b57..a2da05d 100644
--- a/xen/include/public/hvm/params.h
+++ b/xen/include/public/hvm/params.h
@@ -147,6 +147,8 @@
 #define HVM_PARAM_ACCESS_RING_PFN   28
 #define HVM_PARAM_SHARING_RING_PFN  29
 
-#define HVM_NR_PARAMS          30
+#define HVM_PARAM_GRANT_START_PFN 30
+
+#define HVM_NR_PARAMS          31
 
 #endif /* __XEN_PUBLIC_HVM_PARAMS_H__ */
-- 
1.7.2.5