On Mon, 2018-04-16 at 18:28 +0200, Paolo Bonzini wrote:
> On 15/04/2018 00:26, KarimAllah Ahmed wrote:
> >
> > 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.
> >
> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> > Cc: kvm@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: KarimAllah Ahmed <karahmed@xxxxxxxxx>
>
> I'm afraid architectures like ARM 32 need this to be conditional (using
> Kconfig).
Why would using a 64-bit 'requests' be a problem for ARM32? Are you
concerned about performance here or is there some symantic problem?
>
> Thanks,
>
> Paolo
>
> >
> > ---
> > include/linux/kvm_host.h | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index 6930c63..fe4f46b 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -129,7 +129,7 @@ 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) >= (sizeof(((struct kvm_vcpu *)0)->requests) * 8) - KVM_REQUEST_ARCH_BASE); \
> > (unsigned)(((nr) + KVM_REQUEST_ARCH_BASE) | (flags)); \
> > })
> > #define KVM_ARCH_REQ(nr) KVM_ARCH_REQ_FLAGS(nr, 0)
> > @@ -223,7 +223,7 @@ struct kvm_vcpu {
> > int vcpu_id;
> > int srcu_idx;
> > int mode;
> > - unsigned long requests;
> > + u64 requests;
> > unsigned long guest_debug;
> >
> > int pre_pcpu;
> > @@ -1122,7 +1122,7 @@ 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)
> > @@ -1132,12 +1132,12 @@ 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)
> >
>
>
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