On Thu, May 12, 2016 at 07:52:38PM +0100, Andre Przywara wrote:
> Hi,
>
> On 12/05/16 19:47, Christoffer Dall wrote:
> > On Fri, May 06, 2016 at 11:46:00AM +0100, Andre Przywara wrote:
> >> Using the VMCR accessors we provide access to GIC CPU interface state
> >> to userland by wiring it up to the existing userland interface.
> >> [Marc: move and make VMCR accessors static, streamline MMIO handlers]
> >
> > does this mean Marc did this and serves as credit or is it a lost
> > reminder?
>
> It was meant as credit. I thought that is the usual annotation for this?
>
I'm not sure if that's the usual way, I read it as a reminder, but it's
not too important. Mostly wanting to make sure we're not forgetting
some todo item.
> >>
> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> >> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> >> ---
> >> Changelog v2 .. v3:
> >> - total rework, moving into vgic-mmio-v2.c
> >> - move vmcr accessor wrapper functions into this file
> >> - use the register description table for CPU i/f registers as well
> >> - add RAZ/WI handling for the active priority registers
> >> - streamline MMIO handler functions
> >>
> >> virt/kvm/arm/vgic/vgic-kvm-device.c | 2 +-
> >> virt/kvm/arm/vgic/vgic-mmio-v2.c | 104 ++++++++++++++++++++++++++++++++++++
> >> virt/kvm/arm/vgic/vgic.h | 2 +
> >> 3 files changed, 107 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> >> index bb33af8..2122ff2 100644
> >> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> >> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> >> @@ -300,7 +300,7 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
> >>
> >> switch (attr->group) {
> >> case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> >> - ret = -EINVAL;
> >> + ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
> >> break;
> >> case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> >> ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
> >> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> index c453e6f..0060539 100644
> >> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> >> @@ -206,6 +206,84 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu,
> >> }
> >> }
> >>
> >> +static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> >> +{
> >> + if (kvm_vgic_global_state.type == VGIC_V2)
> >> + vgic_v2_set_vmcr(vcpu, vmcr);
> >> + else
> >> + vgic_v3_set_vmcr(vcpu, vmcr);
> >> +}
> >> +
> >> +static void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> >> +{
> >> + if (kvm_vgic_global_state.type == VGIC_V2)
> >> + vgic_v2_get_vmcr(vcpu, vmcr);
> >> + else
> >> + vgic_v3_get_vmcr(vcpu, vmcr);
> >> +}
> >> +
> >> +#define GICC_ARCH_VERSION_V2 0x2
> >> +
> >> +/* These are for userland accesses only, there is no guest-facing emulation. */
> >> +static unsigned long vgic_mmio_read_vcpuif(struct kvm_vcpu *vcpu,
> >> + gpa_t addr, unsigned int len)
> >> +{
> >> + struct vgic_vmcr vmcr;
> >> + u32 val;
> >> +
> >> + vgic_get_vmcr(vcpu, &vmcr);
> >> +
> >> + switch (addr & 0xff) {
> >> + case GIC_CPU_CTRL:
> >> + val = vmcr.ctlr;
> >> + break;
> >> + case GIC_CPU_PRIMASK:
> >> + val = vmcr.pmr;
> >> + break;
> >> + case GIC_CPU_BINPOINT:
> >> + val = vmcr.bpr;
> >> + break;
> >> + case GIC_CPU_ALIAS_BINPOINT:
> >> + val = vmcr.abpr;
> >> + break;
> >> + case GIC_CPU_IDENT:
> >> + val = ((PRODUCT_ID_KVM << 20) |
> >> + (GICC_ARCH_VERSION_V2 << 16) |
> >> + IMPLEMENTER_ARM);
> >> + break;
> >> + default:
> >> + return 0;
> >> + }
> >> +
> >> + return extract_bytes(val, addr & 3, len);
> >
> > I don't think we allow anything than a full 32-bit aligned accesses
> > from userspace - we shouldn't at least.
>
> Indeed - I think userland was always 32-bit only. And since last night
> we even enforce this. So potentially there are more extract_bytes()
> calls that can go.
>
Right.
-Christoffer
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