KVM: Switch 'requests' to be 64-bit (explicitly)

Switch 'requests' to be explicitly 64-bit and update BUILD_BUG_ON check to
use the size of "requests" instead of the hard-coded '32'.

That gives us a bit more room again for arch-specific requests as we
already ran out of space for x86 due to the hard-coded check.

The only exception here is ARM32 as it is still 32-bits.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/linux/kvm_host.h

@@ -130,7 +130,7 @@ static inline bool is_error_page(struct page *page)
 #define KVM_REQUEST_ARCH_BASE     8
 
 #define KVM_ARCH_REQ_FLAGS(nr, flags) ({ \
-	BUILD_BUG_ON((unsigned)(nr) >= 32 - KVM_REQUEST_ARCH_BASE); \
+	BUILD_BUG_ON((unsigned)(nr) >= (FIELD_SIZEOF(struct kvm_vcpu, requests) * 8) - KVM_REQUEST_ARCH_BASE); \
 	(unsigned)(((nr) + KVM_REQUEST_ARCH_BASE) | (flags)); \
 })
 #define KVM_ARCH_REQ(nr)           KVM_ARCH_REQ_FLAGS(nr, 0)
@@ -224,7 +224,7 @@ struct kvm_vcpu {
 	int vcpu_id;
 	int srcu_idx;
 	int mode;
-	unsigned long requests;
+	u64 requests;
 	unsigned long guest_debug;
 
 	int pre_pcpu;
@@ -1131,7 +1131,7 @@ static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu)
 	 * caller.  Paired with the smp_mb__after_atomic in kvm_check_request.
 	 */
 	smp_wmb();
-	set_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
+	set_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests);
 }
 
 static inline bool kvm_request_pending(struct kvm_vcpu *vcpu)
@@ -1141,12 +1141,12 @@ static inline bool kvm_request_pending(struct kvm_vcpu *vcpu)
 
 static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu)
 {
-	return test_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
+	return test_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests);
 }
 
 static inline void kvm_clear_request(int req, struct kvm_vcpu *vcpu)
 {
-	clear_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
+	clear_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests);
 }
 
 static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu)