Fix KVM coverity warnings

[mpe]

*** CID 178601:  Integer handling issues  (BAD_SHIFT)
/arch/powerpc/include/asm/kvm_book3s_64.h: 247 in compute_tlbie_rb()
241     	} else {
242     		int aval_shift;
243     		/*
244     		 * remaining bits of AVA/LP fields
245     		 * Also contain the rr bits of LP
246     		 */
>>>     CID 178601:  Integer handling issues  (BAD_SHIFT)
>>>     In expression "va_low << b_pgshift", shifting by a negative amount has undefined behavior.  The shift amount, "b_pgshift", is -1.
247     		rb |= (va_low << b_pgshift) & 0x7ff000;
248     		/*
249     		 * Now clear not needed LP bits based on actual psize
250     		 */
251     		rb &= ~((1ul << a_pgshift) - 1);
252     		/*

*** CID 178619:  Code maintainability issues  (UNUSED_VALUE)
/arch/powerpc/kvm/book3s_64_mmu_radix.c: 576 in kvmppc_hv_get_dirty_log_radix()
570     		 * Since we have at most one PTE covering any given guest
571     		 * real address, if npages > 1 we can skip to i + npages.
572     		 */
573     		j = i + 1;
574     		if (npages) {
575     			set_dirty_bits(map, i, npages);
>>>     CID 178619:  Code maintainability issues  (UNUSED_VALUE)
>>>     Assigning value from "j + npages" to "i" here, but that stored value is overwritten before it can be used.
576     			i = j + npages;
577     		}
578     	}
579     	return 0;
580     }

*** CID 178617:  Integer handling issues  (BAD_SHIFT)
/arch/powerpc/include/asm/kvm_book3s_64.h: 162 in kvmppc_actual_pgsz()
156     		tmp >>= 8;
157     	return tmp;
158     }
159     
160     static inline unsigned long kvmppc_actual_pgsz(unsigned long v, unsigned long r)
161     {
>>>     CID 178617:  Integer handling issues  (BAD_SHIFT)
>>>     In expression "1UL << kvmppc_hpte_actual_page_shift(v, r)", shifting by a negative amount has undefined behavior.  The shift amount, "kvmppc_hpte_actual_page_shift(v, r)", is -1.
162     	return 1ul << kvmppc_hpte_actual_page_shift(v, r);
163     }
164     
165     static inline int kvmppc_pgsize_lp_encoding(int base_shift, int actual_shift)
166     {
167     	switch (base_shift) {

*** CID 178606:  Insecure data handling  (TAINTED_SCALAR)
/arch/powerpc/kvm/book3s_hv_builtin.c: 658 in wait_for_sync()
652     static void wait_for_sync(struct kvm_split_mode *sip, int phase)
653     {
654     	int thr = local_paca->kvm_hstate.tid;
655     
656     	sip->lpcr_sync.phase[thr] |= phase;
657     	phase = ALL(phase);
>>>     CID 178606:  Insecure data handling  (TAINTED_SCALAR)
>>>     Using tainted variable "phase" as a loop boundary.
658     	while ((sip->lpcr_sync.allphases & phase) != phase) {
659     		HMT_low();
660     		barrier();
661     	}
662     	HMT_medium();
663     }

[paulusmack]

What's the last one on about? All of the callers pass a constant for 'phase', so how is that insecure data?

[mpe]

Not sure. I'll check the coverity web UI tomorrow if you remind me :)