Hello Sergej,
On 01/08/16 18:10, Sergej Proskurin wrote:
Signed-off-by: Sergej Proskurin <prosku...@sec.in.tum.de>
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Julien Grall <julien.gr...@arm.com>
---
v2: Substituted the call to tlb_flush for p2m_flush_table.
Added comments.
Cosmetic fixes.
---
xen/arch/arm/altp2m.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/hvm.c | 2 +-
xen/include/asm-arm/altp2m.h | 4 ++++
3 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/altp2m.c b/xen/arch/arm/altp2m.c
index c22d2e4..80ed553 100644
--- a/xen/arch/arm/altp2m.c
+++ b/xen/arch/arm/altp2m.c
@@ -212,6 +212,56 @@ void altp2m_flush(struct domain *d)
altp2m_unlock(d);
}
+int altp2m_destroy_by_id(struct domain *d, unsigned int idx)
+{
+ struct p2m_domain *p2m;
+ int rc = -EBUSY;
+
+ /*
+ * The altp2m[0] is considered as the hostp2m and is used as a safe harbor
+ * to which you can switch as long as altp2m is active. After deactivating
+ * altp2m, the system switches back to the original hostp2m view. That is,
+ * altp2m[0] should only be destroyed/flushed/freed, when altp2m is
+ * deactivated.
+ */
+ if ( !idx || idx >= MAX_ALTP2M )
+ return rc;
+
+ domain_pause_except_self(d);
+
+ altp2m_lock(d);
+
+ if ( d->arch.altp2m_vttbr[idx] != INVALID_VTTBR )
+ {
+ p2m = d->arch.altp2m_p2m[idx];
+
+ if ( !_atomic_read(p2m->active_vcpus) )
+ {
+ read_lock(&p2m->lock);
Please avoid to use open read_lock and use the p2m_*lock helpers. Also
read lock does not prevent multiple thread to access the p2m at the same
time.
+
+ p2m_flush_table(p2m);
+
+ /*
+ * Reset VTTBR.
+ *
+ * Note that VMID is not freed so that it can be reused later.
+ */
+ p2m->vttbr.vttbr = INVALID_VTTBR;
+ d->arch.altp2m_vttbr[idx] = INVALID_VTTBR;
+
+ read_unlock(&p2m->lock);
Why did you decide to reset the p2m rather than free it? The code would
be simpler with the latter.
+
+ rc = 0;
+ }
+ }
+
+ altp2m_unlock(d);
+
+ domain_unpause_except_self(d);
+
+ return rc;
+}
+
void altp2m_teardown(struct domain *d)
{
unsigned int i;
diff --git a/xen/arch/arm/hvm.c b/xen/arch/arm/hvm.c
index 063a06b..df29cdc 100644
--- a/xen/arch/arm/hvm.c
+++ b/xen/arch/arm/hvm.c
@@ -125,7 +125,7 @@ static int do_altp2m_op(XEN_GUEST_HANDLE_PARAM(void) arg)
break;
case HVMOP_altp2m_destroy_p2m:
- rc = -EOPNOTSUPP;
+ rc = altp2m_destroy_by_id(d, a.u.view.view);
break;
case HVMOP_altp2m_switch_p2m:
diff --git a/xen/include/asm-arm/altp2m.h b/xen/include/asm-arm/altp2m.h
index 3ecae27..afa1580 100644
--- a/xen/include/asm-arm/altp2m.h
+++ b/xen/include/asm-arm/altp2m.h
@@ -60,4 +60,8 @@ int altp2m_init_next(struct domain *d,
/* Flush all the alternate p2m's for a domain */
void altp2m_flush(struct domain *d);
+/* Make a specific alternate p2m invalid */
+int altp2m_destroy_by_id(struct domain *d,
+ unsigned int idx);
+
#endif /* __ASM_ARM_ALTP2M_H */
Regards,
--
Julien Grall
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