ARM: KVM: get rid of S2_PGD_SIZE

S2_PGD_SIZE defines the number of pages used by a stage-2 PGD
and is unused, except for a VM_BUG_ON check that missuses the
define.

As the check is very unlikely to ever triggered except in
circumstances where KVM is the least of our worries, just kill
both the define and the VM_BUG_ON check.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
(cherry picked from commit 4db845c3d8)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

arch/arm/include/asm/kvm_arm.h

@@ -135,7 +135,6 @@
 #define KVM_PHYS_MASK	(KVM_PHYS_SIZE - 1ULL)
 #define PTRS_PER_S2_PGD	(1ULL << (KVM_PHYS_SHIFT - 30))
 #define S2_PGD_ORDER	get_order(PTRS_PER_S2_PGD * sizeof(pgd_t))
-#define S2_PGD_SIZE	(1 << S2_PGD_ORDER)
 
 /* Virtualization Translation Control Register (VTCR) bits */
 #define VTCR_SH0	(3 << 12)

arch/arm/kvm/mmu.c

@@ -382,9 +382,6 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm)
 	if (!pgd)
 		return -ENOMEM;
 
-	/* stage-2 pgd must be aligned to its size */
-	VM_BUG_ON((unsigned long)pgd & (S2_PGD_SIZE - 1));
-
 	memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t));
 	kvm_clean_pgd(pgd);
 	kvm->arch.pgd = pgd;