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commit 9c962e07fbf3d7e2f8f92d8834a60fe7d5600637
Author: Henry Wang <Henry.Wang@arm.com>
AuthorDate: Tue Mar 28 15:13:34 2023 +0800
Commit: Julien Grall <jgrall@amazon.com>
CommitDate: Sun Apr 16 15:41:08 2023 +0100

xen/arm: Clean-up in p2m_init() and p2m_final_teardown()

With the change in previous patch, the initial 16 pages in the P2M
pool is not necessary anymore. Drop them for code simplification.

Also the call to p2m_teardown() from arch_domain_destroy() is not
necessary anymore since the movement of the P2M allocation out of
arch_domain_create(). Drop the code and the above in-code comment
mentioning it. Take the opportunity to fix a typo in the original
in-code comment.

With above clean-up, the second parameter of p2m_teardown() is
also not needed anymore. Drop this parameter and the logic related
to this parameter.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
---
xen/arch/arm/domain.c | 2 +-
xen/arch/arm/include/asm/p2m.h | 14 +++++---------
xen/arch/arm/p2m.c | 24 +++---------------------
3 files changed, 9 insertions(+), 31 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index b8a4a60570..d8ef6501ff 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -1030,7 +1030,7 @@ int domain_relinquish_resources(struct domain *d)
p2m_clear_root_pages(&d->arch.p2m);

PROGRESS(p2m):
- ret = p2m_teardown(d, true);
+ ret = p2m_teardown(d);
if ( ret )
return ret;

diff --git a/xen/arch/arm/include/asm/p2m.h b/xen/arch/arm/include/asm/p2m.h
index bf5183e53a..f67e9ddc72 100644
--- a/xen/arch/arm/include/asm/p2m.h
+++ b/xen/arch/arm/include/asm/p2m.h
@@ -194,18 +194,14 @@ int p2m_init(struct domain *d);

/*
* The P2M resources are freed in two parts:
- * - p2m_teardown() will be called preemptively when relinquish the
- * resources, in which case it will free large resources (e.g. intermediate
- * page-tables) that requires preemption.
+ * - p2m_teardown() will be called when relinquish the resources. It
+ * will free large resources (e.g. intermediate page-tables) that
+ * requires preemption.
* - p2m_final_teardown() will be called when domain struct is been
- * freed. This *cannot* be preempted and therefore one small
+ * freed. This *cannot* be preempted and therefore only small
* resources should be freed here.
- * Note that p2m_final_teardown() will also call p2m_teardown(), to properly
- * free the P2M when failures happen in the domain creation with P2M pages
- * already in use. In this case p2m_teardown() is called non-preemptively and
- * p2m_teardown() will always return 0.
*/
-int p2m_teardown(struct domain *d, bool allow_preemption);
+int p2m_teardown(struct domain *d);
void p2m_final_teardown(struct domain *d);

/*
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index f1ccd7efbd..418997843d 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1713,7 +1713,7 @@ static void p2m_free_vmid(struct domain *d)
spin_unlock(&vmid_alloc_lock);
}

-int p2m_teardown(struct domain *d, bool allow_preemption)
+int p2m_teardown(struct domain *d)
{
struct p2m_domain *p2m = p2m_get_hostp2m(d);
unsigned long count = 0;
@@ -1727,7 +1727,7 @@ int p2m_teardown(struct domain *d, bool allow_preemption)
p2m_free_page(p2m->domain, pg);
count++;
/* Arbitrarily preempt every 512 iterations */
- if ( allow_preemption && !(count % 512) && hypercall_preempt_check() )
+ if ( !(count % 512) && hypercall_preempt_check() )
{
rc = -ERESTART;
break;
@@ -1750,13 +1750,9 @@ void p2m_final_teardown(struct domain *d)
/*
* No need to call relinquish_p2m_mapping() here because
* p2m_final_teardown() is called either after domain_relinquish_resources()
- * where relinquish_p2m_mapping() has been called, or from failure path of
- * domain_create()/arch_domain_create() where mappings that require
- * p2m_put_l3_page() should never be created. For the latter case, also see
- * comment on top of the p2m_set_entry() for more info.
+ * where relinquish_p2m_mapping() has been called.
*/

- BUG_ON(p2m_teardown(d, false));
ASSERT(page_list_empty(&p2m->pages));

while ( p2m_teardown_allocation(d) == -ERESTART )
@@ -1827,20 +1823,6 @@ int p2m_init(struct domain *d)
if ( rc )
return rc;

- /*
- * Hardware using GICv2 needs to create a P2M mapping of 8KB GICv2 area
- * when the domain is created. Considering the worst case for page
- * tables and keep a buffer, populate 16 pages to the P2M pages pool here.
- * For GICv3, the above-mentioned P2M mapping is not necessary, but since
- * the allocated 16 pages here would not be lost, hence populate these
- * pages unconditionally.
- */
- spin_lock(&d->arch.paging.lock);
- rc = p2m_set_allocation(d, 16, NULL);
- spin_unlock(&d->arch.paging.lock);
- if ( rc )
- return rc;
-
return 0;
}

--
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