irqchip/gic-v3-its: Fix over allocation in itt_alloc_pool()

JIRA: https://issues.redhat.com/browse/RHEL-62922

commit bc88d44
Author: Steven Price <steven.price@arm.com>
Date: Mon, 21 Oct 2024 11:41:05 +0100

    itt_alloc_pool() calls its_alloc_pages_node() to allocate an individual
    page to add to the pool (for allocations <PAGE_SIZE). However the final
    argument of its_alloc_pages_node() is the page order not the number of
    pages. Currently it allocates two pages and leaks the second page.
    Fix it by passing 0 instead (1 << 0 = 1 page).

    Fixes: b08e2f4 ("irqchip/gic-v3-its: Share ITS tables with a non-trusted hypervisor")
    Reported-by: Shanker Donthineni <sdonthineni@nvidia.com>
    Signed-off-by: Steven Price <steven.price@arm.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Link: https://lore.kernel.org/all/1f6e19c4-1fb9-43ab-a8a2-a465c9cff84b@arm.com
    Closes: https://lore.kernel.org/r/ed65312a-245c-4fa5-91ad-5d620cab7c6b%40nvidia.com

Signed-off-by: Charles Mirabile <cmirabil@redhat.com>

Author: Charles Mirabile

drivers/irqchip/irq-gic-v3-its.c

@@ -260,7 +260,7 @@ static void *itt_alloc_pool(int node, int size)
 		if (addr)
 			break;
 
-		page = its_alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 1);
+		page = its_alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
 		if (!page)
 			break;