KVM: add kvm_request_pending

A first step in vcpu->requests encapsulation.  Additionally, we now
use READ_ONCE() when accessing vcpu->requests, which ensures we
always load vcpu->requests when it's accessed.  This is important as
other threads can change it any time.  Also, READ_ONCE() documents
that vcpu->requests is used with other threads, likely requiring
memory barriers, which it does.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[ Documented the new use of READ_ONCE() and converted another check
  in arch/mips/kvm/vz.c ]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
This commit is contained in:
Radim Krčmář
2017-06-04 14:43:52 +02:00
committed by Christoffer Dall
parent 2387149ead
commit 2fa6e1e12a
7 changed files with 13 additions and 9 deletions

View File

@@ -1105,6 +1105,11 @@ static inline void kvm_make_request(int req, struct kvm_vcpu *vcpu)
set_bit(req & KVM_REQUEST_MASK, &vcpu->requests);
}
static inline bool kvm_request_pending(struct kvm_vcpu *vcpu)
{
return READ_ONCE(vcpu->requests);
}
static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu)
{
return test_bit(req & KVM_REQUEST_MASK, &vcpu->requests);