[Xen-devel] [PATCH v3 04/38] arm/p2m: Add first altp2m HVMOP stubs

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

This commit moves the altp2m-related code from x86 to ARM. Functions
that are no yet supported notify the caller or print a BUG message
stating their absence.

Also, the struct arch_domain is extended with the altp2m_active
attribute, representing the current altp2m activity configuration of the
domain.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
v2: Removed altp2m command-line option: Guard through HVM_PARAM_ALTP2M.
    Removed not used altp2m helper stubs in altp2m.h.

v3: Cosmetic fixes.

    Added domain lock in "do_altp2m_op" to avoid concurrent execution of
    altp2m-related HVMOPs.

    Added check making sure that HVM_PARAM_ALTP2M is set before
    execution of altp2m-related HVMOPs.
---
 xen/arch/arm/hvm.c           | 89 ++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/altp2m.h |  4 +-
 xen/include/asm-arm/domain.h |  3 ++
 3 files changed, 94 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/hvm.c b/xen/arch/arm/hvm.c
index d999bde..45d51c6 100644
--- a/xen/arch/arm/hvm.c
+++ b/xen/arch/arm/hvm.c
@@ -32,6 +32,91 @@
 
 #include <asm/hypercall.h>
 
+#include <asm/altp2m.h>
+
+static int do_altp2m_op(XEN_GUEST_HANDLE_PARAM(void) arg)
+{
+    struct xen_hvm_altp2m_op a;
+    struct domain *d = NULL;
+    int rc = 0;
+
+    if ( copy_from_guest(&a, arg, 1) )
+        return -EFAULT;
+
+    if ( a.pad1 || a.pad2 ||
+         (a.version != HVMOP_ALTP2M_INTERFACE_VERSION) ||
+         (a.cmd < HVMOP_altp2m_get_domain_state) ||
+         (a.cmd > HVMOP_altp2m_change_gfn) )
+        return -EINVAL;
+
+    d = (a.cmd != HVMOP_altp2m_vcpu_enable_notify) ?
+        rcu_lock_domain_by_any_id(a.domain) : rcu_lock_current_domain();
+
+    if ( d == NULL )
+        return -ESRCH;
+
+    /* Prevent concurrent execution of the following HVMOPs. */
+    domain_lock(d);
+
+    if ( (a.cmd != HVMOP_altp2m_get_domain_state) &&
+         (a.cmd != HVMOP_altp2m_set_domain_state) &&
+         !altp2m_active(d) )
+    {
+        rc = -EOPNOTSUPP;
+        goto out;
+    }
+
+    if ( !(d)->arch.hvm_domain.params[HVM_PARAM_ALTP2M] )
+    {
+        rc = -EINVAL;
+        goto out;
+    }
+
+    if ( (rc = xsm_hvm_altp2mhvm_op(XSM_TARGET, d)) )
+        goto out;
+
+    switch ( a.cmd )
+    {
+    case HVMOP_altp2m_get_domain_state:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_set_domain_state:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_vcpu_enable_notify:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_create_p2m:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_destroy_p2m:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_switch_p2m:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_set_mem_access:
+        rc = -EOPNOTSUPP;
+        break;
+
+    case HVMOP_altp2m_change_gfn:
+        rc = -EOPNOTSUPP;
+        break;
+    }
+
+out:
+    domain_unlock(d);
+    rcu_unlock_domain(d);
+
+    return rc;
+}
+
 long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     long rc = 0;
@@ -80,6 +165,10 @@ long do_hvm_op(unsigned long op, 
XEN_GUEST_HANDLE_PARAM(void) arg)
             rc = -EINVAL;
         break;
 
+    case HVMOP_altp2m:
+        rc = do_altp2m_op(arg);
+        break;
+
     default:
     {
         gdprintk(XENLOG_DEBUG, "HVMOP op=%lu: not implemented\n", op);
diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
index a87747a..0711796 100644
--- a/xen/include/asm-arm/altp2m.h
+++ b/xen/include/asm-arm/altp2m.h
@@ -2,6 +2,7 @@
  * Alternate p2m
  *
  * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2016, Sergej Proskurin <proskurin@xxxxxxxxxxxxx>.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -24,8 +25,7 @@
 /* Alternate p2m on/off per domain */
 static inline bool_t altp2m_active(const struct domain *d)
 {
-    /* Not implemented on ARM. */
-    return 0;
+    return d->arch.altp2m_active;
 }
 
 /* Alternate p2m VCPU */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 9452fcd..cc4bda0 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -126,6 +126,9 @@ struct arch_domain
     paddr_t efi_acpi_gpa;
     paddr_t efi_acpi_len;
 #endif
+
+    /* altp2m: allow multiple copies of host p2m */
+    bool_t altp2m_active;
 }  __cacheline_aligned;
 
 struct arch_vcpu
-- 
2.9.0


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