[PATCH v02 6/7] arm: introduce do_translate_pagetable hypercall

[Andrii Tseglytskyi <andrii.tseglytskyi@globallogic.com>]

The reason of the patch is the following - some remoteprocs
are quite complicated, and their MMUs can handle several
pagetables. Good example is a OMAP5 GPU, which allocates
several pagetables during it work. Additional requirement
is that not all pagetable physical addresses are stored
in MMU registers. Some pagetables may be allocated and
then their physical addresses are sent to GPU using private
message loop between GPU kernel driver and GPU remoteproc.

Patch is developed to handle this. At any moment of time
kernel can perform translation of such pagetables, before
sending their addresses to GPU remoteproc.

Change-Id: Ie84012163205c3a2f920dc4cf07327a244647c93
Signed-off-by: Andrii Tseglytskyi <andrii.tseglytskyi@globallogic.com>
---
 xen/arch/arm/remoteproc_iommu.c |   22 ++++++++++++++++++++++
 xen/arch/arm/traps.c            |    1 +
 xen/include/public/xen.h        |    1 +
 xen/include/xen/hypercall.h     |   12 ++++++++++++
 4 files changed, 36 insertions(+)

diff --git a/xen/arch/arm/remoteproc_iommu.c b/xen/arch/arm/remoteproc_iommu.c
index 3b3da3b..316ceb4 100644
--- a/xen/arch/arm/remoteproc_iommu.c
+++ b/xen/arch/arm/remoteproc_iommu.c
@@ -23,6 +23,8 @@
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <xen/stdbool.h>
+#include <xen/hypercall.h>
+#include <xen/guest_access.h>
 #include <asm/system.h>
 #include <asm/current.h>
 #include <asm/io.h>
@@ -382,6 +384,26 @@ static int mmu_init(struct mmu_info *mmu, u32 data)
     return 0;
 }
 
+long do_translate_pagetable(int cmd, XEN_GUEST_HANDLE_PARAM(xen_pagetable_addr_t) pgt_addr)
+{
+    struct xen_pagetable_addr pgt;
+    struct mmu_info *mmu = NULL;
+
+    if ( copy_from_guest(&pgt, pgt_addr, 1) )
+        return -EFAULT;
+
+    mmu = mmu_lookup(pgt.reg);
+    if ( !mmu )
+    {
+        pr_mmu("can't get mmu for addr 0x%08x", pgt.reg);
+        return -EINVAL;
+    }
+
+    pgt.maddr = mmu_translate_pagetable(mmu, pgt.paddr);
+
+    return copy_to_guest(pgt_addr, &pgt, 1);
+}
+
 static int mmu_init_all(void)
 {
     int res;
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 21c7b26..05b5184 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1012,6 +1012,7 @@ static arm_hypercall_t arm_hypercall_table[] = {
     HYPERCALL(hvm_op, 2),
     HYPERCALL(grant_table_op, 3),
     HYPERCALL_ARM(vcpu_op, 3),
+    HYPERCALL(translate_pagetable, 2),
 };
 
 typedef int (*arm_psci_fn_t)(uint32_t, register_t);
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 8c5697e..91ca6a1 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -101,6 +101,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
 #define __HYPERVISOR_kexec_op             37
 #define __HYPERVISOR_tmem_op              38
 #define __HYPERVISOR_xc_reserved_op       39 /* reserved for XenClient */
+#define __HYPERVISOR_translate_pagetable  40
 
 /* Architecture-specific hypercall definitions. */
 #define __HYPERVISOR_arch_0               48
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index a9e5229..a025435 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -136,6 +136,18 @@ extern long
 do_tmem_op(
     XEN_GUEST_HANDLE_PARAM(tmem_op_t) uops);
 
+struct xen_pagetable_addr {
+	u32 reg;
+	u32 paddr;
+	u32 maddr;
+};
+typedef struct xen_pagetable_addr xen_pagetable_addr_t;
+DEFINE_XEN_GUEST_HANDLE(xen_pagetable_addr_t);
+
+extern long
+do_translate_pagetable(
+	int cmd, XEN_GUEST_HANDLE_PARAM(xen_pagetable_addr_t) pgt_addr);
+
 extern long
 do_xenoprof_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg);
 
-- 
1.7.9.5