[PATCH v5 02/10] irqchip/gic-v3-its: Align shared ITS allocations to the CoCo shared granule size

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

ITS tables allocated by the coco guest are shared with the hypervisor.
These allocations must satisfy the host shared-buffer granule size so that
the full converted range is safe for host access.

Allocate ITS pages using a size rounded up to the shared granule size and
use the same allocation order when encrypting, decrypting and freeing the
memory. Also grow the ITT cache in shared-granule sized chunks instead of
assuming PAGE_SIZE is sufficient.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 drivers/irqchip/irq-gic-v3-its.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index b57d81ad33a0..5d6d38aa0dae 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -213,16 +213,17 @@ static gfp_t gfp_flags_quirk;
 static struct page *its_alloc_pages_node(int node, gfp_t gfp,
 					 unsigned int order)
 {
+	unsigned int alloc_order;
 	struct page *page;
 	int ret = 0;
 
-	page = alloc_pages_node(node, gfp | gfp_flags_quirk, order);
-
+	alloc_order = get_order(mem_cc_align_to_shared_granule(PAGE_SIZE << order));
+	page = alloc_pages_node(node, gfp | gfp_flags_quirk, alloc_order);
 	if (!page)
 		return NULL;
 
 	ret = set_memory_decrypted((unsigned long)page_address(page),
-				   1 << order);
+				   1 << alloc_order);
 	/*
 	 * If set_memory_decrypted() fails then we don't know what state the
 	 * page is in, so we can't free it. Instead we leak it.
@@ -241,13 +242,16 @@ static struct page *its_alloc_pages(gfp_t gfp, unsigned int order)
 
 static void its_free_pages(void *addr, unsigned int order)
 {
+	int alloc_order;
+
+	alloc_order = get_order(mem_cc_align_to_shared_granule(PAGE_SIZE << order));
 	/*
 	 * If the memory cannot be encrypted again then we must leak the pages.
 	 * set_memory_encrypted() will already have WARNed.
 	 */
-	if (set_memory_encrypted((unsigned long)addr, 1 << order))
+	if (set_memory_encrypted((unsigned long)addr, 1 << alloc_order))
 		return;
-	free_pages((unsigned long)addr, order);
+	free_pages((unsigned long)addr, alloc_order);
 }
 
 static struct gen_pool *itt_pool;
@@ -272,7 +276,8 @@ static void *itt_alloc_pool(int node, int size)
 		if (!page)
 			break;
 
-		gen_pool_add(itt_pool, (unsigned long)page_address(page), PAGE_SIZE, node);
+		gen_pool_add(itt_pool, (unsigned long)page_address(page),
+			     mem_cc_align_to_shared_granule(PAGE_SIZE), node);
 	} while (!addr);
 
 	return (void *)addr;
-- 
2.43.0