Re: [PATCH 8/8] KVM: PPC: Add hugepage support for IOMMU in-kernelhandling

From: Scott Wood
Date: Thu Jun 27 2013 - 14:39:48 EST


On 06/27/2013 12:02:36 AM, Alexey Kardashevskiy wrote:
+/*
+ * The KVM guest can be backed with 16MB pages.
+ * In this case, we cannot do page counting from the real mode
+ * as the compound pages are used - they are linked in a list
+ * with pointers as virtual addresses which are inaccessible
+ * in real mode.
+ *
+ * The code below keeps a 16MB pages list and uses page struct
+ * in real mode if it is already locked in RAM and inserted into
+ * the list or switches to the virtual mode where it can be
+ * handled in a usual manner.
+ */
+#define KVMPPC_HUGEPAGE_HASH(gpa) hash_32(gpa >> 24, 32)
+
+struct kvmppc_iommu_hugepage {
+ struct hlist_node hash_node;
+ unsigned long gpa; /* Guest physical address */
+ unsigned long hpa; /* Host physical address */
+ struct page *page; /* page struct of the very first subpage */
+ unsigned long size; /* Huge page size (always 16MB at the moment) */
+};

Shouldn't this be namespaced to something like "book3s" or "spapr"?

-Scott
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