[Xen-devel] [PATCH v4 12/39] arm/p2m: Add altp2m init/teardown routines

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

The p2m initialization now invokes initialization routines responsible
for the allocation and initialization of altp2m structures. The same
applies to teardown routines. The functionality has been adopted from
the x86 altp2m implementation.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
v2: Shared code between host/altp2m init/teardown functions.
    Added conditional init/teardown of altp2m.
    Altp2m related functions are moved to altp2m.c

v3: Removed locking the altp2m_lock in altp2m_teardown. Locking this
    lock at this point is unnecessary.

    Removed re-setting altp2m_vttbr, altp2m_p2m, and altp2m_active
    values in the function "altp2m_teardown". Re-setting these values is
    unnecessary as the entire domain will be destroyed right afterwards.

    Removed check for "altp2m_enabled" in "p2m_init" as altp2m has not yet
    been enabled by libxl at this point.

    Removed check for "altp2m_enabled" before tearing down altp2m within
    the function "p2m_teardown" so that altp2m gets destroyed even if
    the HVM_PARAM_ALTP2M gets reset before "p2m_teardown" is called.

    Added initialization of the field d->arch.altp2m_active in
    "altp2m_init".

    Removed check for already initialized vmid's in "altp2m_init_one",
    as "altp2m_init_one" is now called always with an uninitialized p2m.

    Removed the array altp2m_vttbr[] in struct arch_domain.

v4: Removed initialization of altp2m_p2m[] to NULL in altp2m_init, as
    the "struct arch_domain" is already initialized to zero.

    We moved the definition of the macro MAX_ALTP2M to a common place in
    a separate commit.
---
 xen/arch/arm/Makefile        |  1 +
 xen/arch/arm/altp2m.c        | 56 ++++++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/p2m.c           | 15 +++++++++++-
 xen/include/asm-arm/altp2m.h |  6 +++++
 xen/include/asm-arm/domain.h | 11 ++++++++-
 5 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 xen/arch/arm/altp2m.c

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 282d2c2949..a08683335d 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -5,6 +5,7 @@ subdir-$(CONFIG_ARM_64) += efi
 subdir-$(CONFIG_ACPI) += acpi
 
 obj-$(CONFIG_HAS_ALTERNATIVE) += alternative.o
+obj-y += altp2m.o
 obj-y += bootfdt.init.o
 obj-y += cpu.o
 obj-y += cpuerrata.o
diff --git a/xen/arch/arm/altp2m.c b/xen/arch/arm/altp2m.c
new file mode 100644
index 0000000000..e73b69d99d
--- /dev/null
+++ b/xen/arch/arm/altp2m.c
@@ -0,0 +1,56 @@
+/*
+ * arch/arm/altp2m.c
+ *
+ * Alternate p2m
+ * 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, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <asm/p2m.h>
+#include <asm/altp2m.h>
+
+int altp2m_init(struct domain *d)
+{
+    spin_lock_init(&d->arch.altp2m_lock);
+    d->arch.altp2m_active = false;
+
+    return 0;
+}
+
+void altp2m_teardown(struct domain *d)
+{
+    unsigned int i;
+    struct p2m_domain *p2m;
+
+    for ( i = 0; i < MAX_ALTP2M; i++ )
+    {
+        p2m = d->arch.altp2m_p2m[i];
+
+        if ( !p2m )
+            continue;
+
+        p2m_teardown_one(p2m);
+        xfree(p2m);
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index ec855341b9..e017e2972e 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -14,6 +14,7 @@
 #include <asm/event.h>
 #include <asm/hardirq.h>
 #include <asm/page.h>
+#include <asm/altp2m.h>
 
 #define MAX_VMID_8_BIT  (1UL << 8)
 #define MAX_VMID_16_BIT (1UL << 16)
@@ -1305,6 +1306,12 @@ static void p2m_teardown_hostp2m(struct domain *d)
 
 void p2m_teardown(struct domain *d)
 {
+    /*
+     * Teardown altp2m unconditionally so that altp2m gets always destroyed --
+     * even if HVM_PARAM_ALTP2M gets reset before teardown.
+     */
+    altp2m_teardown(d);
+
     p2m_teardown_hostp2m(d);
 }
 
@@ -1319,7 +1326,13 @@ static int p2m_init_hostp2m(struct domain *d)
 
 int p2m_init(struct domain *d)
 {
-    return p2m_init_hostp2m(d);
+    int rc;
+
+    rc = p2m_init_hostp2m(d);
+    if ( rc )
+        return rc;
+
+    return altp2m_init(d);
 }
 
 /*
diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
index 66afa959f6..1706f61f0c 100644
--- a/xen/include/asm-arm/altp2m.h
+++ b/xen/include/asm-arm/altp2m.h
@@ -23,6 +23,9 @@
 #include <xen/altp2m-common.h>
 #include <xen/sched.h>
 
+#define altp2m_lock(d)    spin_lock(&(d)->arch.altp2m_lock)
+#define altp2m_unlock(d)  spin_unlock(&(d)->arch.altp2m_lock)
+
 /* Alternate p2m on/off per domain */
 static inline bool_t altp2m_active(const struct domain *d)
 {
@@ -37,4 +40,7 @@ static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v)
     return 0;
 }
 
+int altp2m_init(struct domain *d);
+void altp2m_teardown(struct domain *d);
+
 #endif /* __ASM_ARM_ALTP2M_H */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 0991a0a79d..668f398dbf 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -1,6 +1,7 @@
 #ifndef __ASM_DOMAIN_H__
 #define __ASM_DOMAIN_H__
 
+#include <xen/altp2m-common.h>
 #include <xen/cache.h>
 #include <xen/sched.h>
 #include <asm/page.h>
@@ -146,8 +147,16 @@ struct arch_domain
         uint8_t privileged_call_enabled : 1;
     } monitor;
 
-    /* altp2m: allow multiple copies of the host's p2m */
+    /*
+     * Lock that protects critical altp2m operations that must not be performed
+     * concurrently.
+     */
+    spinlock_t altp2m_lock;
+
+    /* Altp2m: allow multiple copies of the host's p2m. */
     bool altp2m_active;
+
+    struct p2m_domain *altp2m_p2m[MAX_ALTP2M];
 }  __cacheline_aligned;
 
 struct arch_vcpu
-- 
2.13.3


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