KVM: x86: hyper-v: fix type of valid_bank_mask

In kvm_hv_flush_tlb(), valid_bank_mask is declared as unsigned long,
but is used as u64, which is wrong for i386, and has been spotted by
LKP after applying "KVM: x86: hyper-v: replace bitmap_weight() with
hweight64()"

https://lore.kernel.org/lkml/[email protected]/

But it's wrong even without that patch because now bitmap_weight()
dereferences a word after valid_bank_mask on i386.

>> include/asm-generic/bitops/const_hweight.h:21:76: warning: right shift count >= width of type
+[-Wshift-count-overflow]
      21 | #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
         |                                                                            ^~
   include/asm-generic/bitops/const_hweight.h:10:16: note: in definition of macro '__const_hweight8'
      10 |          ((!!((w) & (1ULL << 0))) +     \
         |                ^
   include/asm-generic/bitops/const_hweight.h:20:31: note: in expansion of macro '__const_hweight16'
      20 | #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
         |                               ^~~~~~~~~~~~~~~~~
   include/asm-generic/bitops/const_hweight.h:21:54: note: in expansion of macro '__const_hweight32'
      21 | #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
         |                                                      ^~~~~~~~~~~~~~~~~
   include/asm-generic/bitops/const_hweight.h:29:49: note: in expansion of macro '__const_hweight64'
      29 | #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
         |                                                 ^~~~~~~~~~~~~~~~~
   arch/x86/kvm/hyperv.c:1983:36: note: in expansion of macro 'hweight64'
    1983 |                 if (hc->var_cnt != hweight64(valid_bank_mask))
         |                                    ^~~~~~~~~

CC: Borislav Petkov <[email protected]>
CC: Dave Hansen <[email protected]>
CC: H. Peter Anvin <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Jim Mattson <[email protected]>
CC: Joerg Roedel <[email protected]>
CC: Paolo Bonzini <[email protected]>
CC: Sean Christopherson <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Vitaly Kuznetsov <[email protected]>
CC: Wanpeng Li <[email protected]>
CC: [email protected]
CC: [email protected]
CC: [email protected]
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Yury Norov <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Author: YuryNorov

arch/x86/kvm/hyperv.c

@@ -1938,7 +1938,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
 	struct hv_send_ipi_ex send_ipi_ex;
 	struct hv_send_ipi send_ipi;
 	DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS);
-	unsigned long valid_bank_mask;
+	u64 valid_bank_mask;
 	u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
 	u32 vector;
 	bool all_cpus;
@@ -1980,7 +1980,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
 		valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask;
 		all_cpus = send_ipi_ex.vp_set.format == HV_GENERIC_SET_ALL;
 
-		if (hc->var_cnt != bitmap_weight(&valid_bank_mask, 64))
+		if (hc->var_cnt != bitmap_weight((unsigned long *)&valid_bank_mask, 64))
 			return HV_STATUS_INVALID_HYPERCALL_INPUT;
 
 		if (all_cpus)