| Message ID | 1411420350-368-2-git-send-email-christoffer.dall@linaro.org |
|---|---|
| State | Accepted |
| Commit | 1f2bb4acc125edc2c06db3ad3e8c699bc075ad52 |
| Headers | show |
On Mon, Sep 22, 2014 at 10:12:30PM +0100, Christoffer Dall wrote: > We were using an atomic bitop on the vgic_v2.vgic_elrsr field which was > not aligned to the natural size on 64-bit platforms. This bug showed up > after QEMU correctly identifies the pl011 line as being level-triggered, > and not edge-triggered. > > These data structures are protected by a spinlock so simply use a > non-atomic version of the accessor instead. > > Tested-by: Joel Schopp <joel.schopp@amd.com> > Reported-by: Riku Voipio <riku.voipio@linaro.org> > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > virt/kvm/arm/vgic-v2.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/virt/kvm/arm/vgic-v2.c b/virt/kvm/arm/vgic-v2.c > index 01124ef..416baed 100644 > --- a/virt/kvm/arm/vgic-v2.c > +++ b/virt/kvm/arm/vgic-v2.c > @@ -71,7 +71,7 @@ static void vgic_v2_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr, > struct vgic_lr lr_desc) > { > if (!(lr_desc.state & LR_STATE_MASK)) > - set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); > + __set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); > } Does this work for big-endian arm64 machines? Surely the bug is due to casting a u32 * to an unsigned long *, and not specifically related to atomics (which is where it happened to explode)? Will
Il 23/09/2014 00:07, Will Deacon ha scritto: >> > { >> > if (!(lr_desc.state & LR_STATE_MASK)) >> > - set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); >> > + __set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); >> > } > Does this work for big-endian arm64 machines? Surely the bug is due to > casting a u32 * to an unsigned long *, and not specifically related to > atomics (which is where it happened to explode)? I agree, this doesn't seem to be the right fix. Paolo
diff --git a/virt/kvm/arm/vgic-v2.c b/virt/kvm/arm/vgic-v2.c index 01124ef..416baed 100644 --- a/virt/kvm/arm/vgic-v2.c +++ b/virt/kvm/arm/vgic-v2.c @@ -71,7 +71,7 @@ static void vgic_v2_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc) { if (!(lr_desc.state & LR_STATE_MASK)) - set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); + __set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr); } static u64 vgic_v2_get_elrsr(const struct kvm_vcpu *vcpu)