Revert "KVM: MMU: fast invalidate all pages"

Remove x86 KVM's fast invalidate mechanism, i.e. revert all patches
from the original series[1], now that all users of the fast invalidate
mechanism are gone.

This reverts commit 5304b8d37c.

[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com

Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -334,7 +334,6 @@ struct kvm_mmu_page {
 	int root_count;          /* Currently serving as active root */
 	unsigned int unsync_children;
 	struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
-	unsigned long mmu_valid_gen;
 	DECLARE_BITMAP(unsync_child_bitmap, 512);
 
 #ifdef CONFIG_X86_32
@@ -845,7 +844,6 @@ struct kvm_arch {
 	unsigned int n_requested_mmu_pages;
 	unsigned int n_max_mmu_pages;
 	unsigned int indirect_shadow_pages;
-	unsigned long mmu_valid_gen;
 	struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
 	/*
 	 * Hash table of struct kvm_mmu_page.