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Re: [Xen-devel] [PATCH v2 07/25] arm/altp2m: Add altp2m init/teardown routines.
Hello Sergej,
On 01/08/16 18:10, Sergej Proskurin wrote:
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
---
xen/arch/arm/Makefile | 1 +
xen/arch/arm/altp2m.c | 71 ++++++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/p2m.c | 28 +++++++++++++----
xen/include/asm-arm/altp2m.h | 6 ++++
xen/include/asm-arm/domain.h | 4 +++
xen/include/asm-arm/p2m.h | 5 ++++
6 files changed, 110 insertions(+), 5 deletions(-)
create mode 100644 xen/arch/arm/altp2m.c
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 23aaf52..4a7f660 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_ALTERNATIVE) += alternative.o
+obj-y += altp2m.o
obj-y += bootfdt.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 0000000..abbd39a
--- /dev/null
+++ b/xen/arch/arm/altp2m.c
@@ -0,0 +1,71 @@
+/*
+ * 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)
+{
+ unsigned int i;
+
+ spin_lock_init(&d->arch.altp2m_lock);
+
+ for ( i = 0; i < MAX_ALTP2M; i++ )
+ {
+ d->arch.altp2m_p2m[i] = NULL;
+ d->arch.altp2m_vttbr[i] = INVALID_VTTBR;
I don't think altp2m_vttbr is useful. There is no real performance
impact to free the whole altp2m if the altp2m is destroyed (see
altp2m_destroy_by_id) and re-allocated afterwards.
The code will actually much simpler. With this solution you will be able
to detect if an altp2m is available by testin altp2m_p2m[i] is NULL.
+ }
+
+ return 0;
+}
+
+void altp2m_teardown(struct domain *d)
+{
+ unsigned int i;
+ struct p2m_domain *p2m;
+
+ altp2m_lock(d);
The lock is not necessary here.
+
+ for ( i = 0; i < MAX_ALTP2M; i++ )
+ {
+ if ( !d->arch.altp2m_p2m[i] )
+ continue;
+
+ p2m = d->arch.altp2m_p2m[i];
+ p2m_free_one(p2m);
+ xfree(p2m);
+
+ d->arch.altp2m_vttbr[i] = INVALID_VTTBR;
+ d->arch.altp2m_p2m[i] = NULL;
The domain will never be used afterward, so there is no point to set
altp2m_vttbr and altp2m_p2m.
+ }
+
+ d->arch.altp2m_active = false;
Ditto.
+
+ altp2m_unlock(d);
+}
+
+/*
+ * 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 ff9c0d1..29ec5e5 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -14,6 +14,8 @@
#include <asm/hardirq.h>
#include <asm/page.h>
+#include <asm/altp2m.h>
+
#ifdef CONFIG_ARM_64
static unsigned int __read_mostly p2m_root_order;
static unsigned int __read_mostly p2m_root_level;
@@ -1392,7 +1394,7 @@ void p2m_flush_table(struct p2m_domain *p2m)
free_domheap_page(pg);
}
-static inline void p2m_free_one(struct p2m_domain *p2m)
+void p2m_free_one(struct p2m_domain *p2m)
Please expose p2m_free_one in patch #4.
{
p2m_flush_table(p2m);
@@ -1415,9 +1417,13 @@ int p2m_init_one(struct domain *d, struct p2m_domain
*p2m)
rwlock_init(&p2m->lock);
INIT_PAGE_LIST_HEAD(&p2m->pages);
- rc = p2m_alloc_vmid(p2m);
- if ( rc != 0 )
- return rc;
+ /* Reused altp2m views keep their VMID. */
+ if ( p2m->vmid == INVALID_VMID )
+ {
+ rc = p2m_alloc_vmid(p2m);
+ if ( rc != 0 )
+ return rc;
+ }
My suggestion above will avoid this kind of hack.
p2m->domain = d;
p2m->access_required = false;
@@ -1441,6 +1447,9 @@ static void p2m_teardown_hostp2m(struct domain *d)
void p2m_teardown(struct domain *d)
{
+ if ( altp2m_enabled(d) )
+ altp2m_teardown(d);
+
p2m_teardown_hostp2m(d);
}
@@ -1460,7 +1469,16 @@ 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;
+
+ if ( altp2m_enabled(d) )
I am a bit skeptical that you can fully use altp2m with this check.
p2m_init is created at the very beginning when the domain is allocated.
So the HVM_PARAM_ALTP2M will not be set.
+ rc = altp2m_init(d);
+
+ return rc;
}
int relinquish_p2m_mapping(struct domain *d)
diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
index d47b249..79ea66b 100644
--- a/xen/include/asm-arm/altp2m.h
+++ b/xen/include/asm-arm/altp2m.h
@@ -22,6 +22,9 @@
#include <xen/sched.h>
+#define altp2m_lock(d) spin_lock(&(d)->arch.altp2m_lock)
+#define altp2m_unlock(d) spin_unlock(&(d)->arch.altp2m_lock)
+
#define altp2m_enabled(d) ((d)->arch.hvm_domain.params[HVM_PARAM_ALTP2M])
/* Alternate p2m on/off per domain */
@@ -38,4 +41,7 @@ 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 cc4bda0..3c25ea5 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -129,6 +129,10 @@ struct arch_domain
/* altp2m: allow multiple copies of host p2m */
bool_t altp2m_active;
+ struct p2m_domain *altp2m_p2m[MAX_ALTP2M];
+ uint64_t altp2m_vttbr[MAX_ALTP2M];
+ /* Covers access to members of the struct altp2m. */
I cannot find any "struct altp2m" in the code.
+ spinlock_t altp2m_lock;
} __cacheline_aligned;
struct arch_vcpu
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 1f9c370..24a1f61 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -9,6 +9,8 @@
#include <xen/p2m-common.h>
#include <public/memory.h>
+#define MAX_ALTP2M 10 /* ARM might contain an arbitrary number of
+ altp2m views. */
#define paddr_bits PADDR_BITS
/* Holds the bit size of IPAs in p2m tables. */
@@ -212,6 +214,9 @@ void guest_physmap_remove_page(struct domain *d,
mfn_t gfn_to_mfn(struct domain *d, gfn_t gfn);
+/* Release resources held by the p2m structure. */
+void p2m_free_one(struct p2m_domain *p2m);
+
/*
* Populate-on-demand
*/
Regards,
--
Julien Grall
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