On 12/8/22 20:38, David Matlack wrote:
+/*
+ * kvm_mmu_page_role tracks the properties of a shadow page (where shadow page
+ * also includes TDP pages) to determine whether or not a page can be used in
+ * the given MMU context.
+ */
+union kvm_mmu_page_role {
+ u32 word;
+ struct {
+ struct {
+ /* The address space ID mapped by the page. */
+ u16 as_id:8;
+
+ /* The level of the page in the page table hierarchy. */
+ u16 level:4;
+
+ /* Whether the page is invalid, i.e. pending destruction. */
+ u16 invalid:1;
+ };
+
+ /* Architecture-specific properties. */
+ struct kvm_mmu_page_role_arch arch;
+ };
+};
+
Have you considered adding a tdp_mmu:1 field to the arch-independent
part? I think that as long as _that_ field is the same, there's no need
to have any overlap between TDP MMU and shadow MMU roles.
I'm not even sure if the x86 TDP MMU needs _any_ other role bit. It
needs of course the above three, and it also needs "direct" but it is
used exactly to mean "is this a TDP MMU page". So we could have
union {
struct {
u32 tdp_mmu:1;
u32 invalid:1;
u32 :6;
u32 level:8;
u32 arch:8;
u32 :8;
} tdp;
/* the first field must be "u32 tdp_mmu:1;" */
struct kvm_mmu_page_role_arch shadow;
};
Paolo
