KVM: arm64: Add flags to kvm_hyp_memcache

Add flags to kvm_hyp_memcache and propagate the latter to the allocation
and free callbacks. This will later allow to account for memory, based
on the memcache configuration.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250313114038.1502357-2-vdonnefort@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: vdonnefort

arch/arm64/include/asm/kvm_host.h

@@ -86,6 +86,7 @@ struct kvm_hyp_memcache {
 	phys_addr_t head;
 	unsigned long nr_pages;
 	struct pkvm_mapping *mapping; /* only used from EL1 */
+	unsigned long flags;
 };
 
 static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc,

arch/arm64/kvm/mmu.c

@@ -1086,12 +1086,12 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 	}
 }
 
-static void hyp_mc_free_fn(void *addr, void *unused)
+static void hyp_mc_free_fn(void *addr, void *mc)
 {
 	free_page((unsigned long)addr);
 }
 
-static void *hyp_mc_alloc_fn(void *unused)
+static void *hyp_mc_alloc_fn(void *mc)
 {
 	return (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
 }
@@ -1102,7 +1102,7 @@ void free_hyp_memcache(struct kvm_hyp_memcache *mc)
 		return;
 
 	kfree(mc->mapping);
-	__free_hyp_memcache(mc, hyp_mc_free_fn, kvm_host_va, NULL);
+	__free_hyp_memcache(mc, hyp_mc_free_fn, kvm_host_va, mc);
 }
 
 int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
@@ -1117,7 +1117,7 @@ int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
 	}
 
 	return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn,
-				    kvm_host_pa, NULL);
+				    kvm_host_pa, mc);
 }
 
 /**