On Tue, Aug 30, 2016 at 6:01 PM, Christoffer Dall < [email protected]> wrote:
> On Wed, Aug 24, 2016 at 04:50:06PM +0530, [email protected] wrote: > > From: Vijaya Kumar K <[email protected]> > > > > VGICv3 Distributor and Redistributor registers are accessed using > > KVM_DEV_ARM_VGIC_GRP_DIST_REGS and KVM_DEV_ARM_VGIC_GRP_DIST_REGS > > with KVM_SET_DEVICE_ATTR and KVM_GET_DEVICE_ATTR ioctls. > > These registers are accessed as 32-bit and cpu mpidr > > value passed along with register offset is used to identify the > > cpu for redistributor registers access. > > > > The version of VGIC v3 specification is define here > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016- > July/445611.html > > > > Signed-off-by: Vijaya Kumar K <[email protected]> > > --- > > arch/arm64/include/uapi/asm/kvm.h | 3 + > > virt/kvm/arm/vgic/vgic-kvm-device.c | 127 > +++++++++++++++++++++++++++++++++++- > > virt/kvm/arm/vgic/vgic-mmio-v3.c | 113 > ++++++++++++++++++++++++++++++++ > > virt/kvm/arm/vgic/vgic-mmio.c | 2 +- > > virt/kvm/arm/vgic/vgic.h | 8 +++ > > 5 files changed, 250 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm64/include/uapi/asm/kvm.h > b/arch/arm64/include/uapi/asm/kvm.h > > index 3051f86..94ea676 100644 > > --- a/arch/arm64/include/uapi/asm/kvm.h > > +++ b/arch/arm64/include/uapi/asm/kvm.h > > @@ -201,10 +201,13 @@ struct kvm_arch_memory_slot { > > #define KVM_DEV_ARM_VGIC_GRP_CPU_REGS 2 > > #define KVM_DEV_ARM_VGIC_CPUID_SHIFT 32 > > #define KVM_DEV_ARM_VGIC_CPUID_MASK (0xffULL << > KVM_DEV_ARM_VGIC_CPUID_SHIFT) > > +#define KVM_DEV_ARM_VGIC_V3_CPUID_MASK \ > > + (0xffffffffULL << > KVM_DEV_ARM_VGIC_CPUID_SHIFT) > > I think this should be KVM_DEV_ARM_VGIC_V3_MPIDR_MASK, and I would > probably define a V3 of the shift as well, since we're really talking > about two distinct APIs here. > > > #define KVM_DEV_ARM_VGIC_OFFSET_SHIFT 0 > > #define KVM_DEV_ARM_VGIC_OFFSET_MASK (0xffffffffULL << > KVM_DEV_ARM_VGIC_OFFSET_SHIFT) > > #define KVM_DEV_ARM_VGIC_GRP_NR_IRQS 3 > > #define KVM_DEV_ARM_VGIC_GRP_CTRL 4 > > +#define KVM_DEV_ARM_VGIC_GRP_REDIST_REGS 5 > > #define KVM_DEV_ARM_VGIC_CTRL_INIT 0 > > > > /* Device Control API on vcpu fd */ > > diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c > b/virt/kvm/arm/vgic/vgic-kvm-device.c > > index 163b057..06f0158 100644 > > --- a/virt/kvm/arm/vgic/vgic-kvm-device.c > > +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c > > @@ -433,16 +433,136 @@ struct kvm_device_ops kvm_arm_vgic_v2_ops = { > > > > #ifdef CONFIG_KVM_ARM_VGIC_V3 > > > > +static int parse_vgic_v3_attr(struct kvm_device *dev, > > + struct kvm_device_attr *attr, > > + struct vgic_reg_attr *reg_attr) > > +{ > > + int cpuid; > > + > > + cpuid = (attr->attr & KVM_DEV_ARM_VGIC_V3_CPUID_MASK) >> > > + KVM_DEV_ARM_VGIC_CPUID_SHIFT; > > + > > + if (cpuid >= atomic_read(&dev->kvm->online_vcpus)) > > + return -EINVAL; > > huh? it's an MPIDR, not a cpu id. > > just resolve it with kvm_mpidr_to_vcpu and check its return value. > > > > + > > + reg_attr->vcpu = kvm_mpidr_to_vcpu(dev->kvm, cpuid); > > please check the return value of this function in any case... > > > + reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK; > > + > > + return 0; > > +} > > + > > +/** > > + * vgic_attr_regs_access_v3 - allows user space to access VGIC v3 state > > + * > > + * @dev: kvm device handle > > + * @attr: kvm device attribute > > + * @reg: address the value is read or written > > + * @is_write: true if userspace is writing a register > > + */ > > +static int vgic_attr_regs_access_v3(struct kvm_device *dev, > > + struct kvm_device_attr *attr, > > + u64 *reg, bool is_write) > > +{ > > + struct vgic_reg_attr reg_attr; > > + gpa_t addr; > > + struct kvm_vcpu *vcpu; > > + int ret; > > + u32 tmp32; > > + > > + ret = parse_vgic_v3_attr(dev, attr, ®_attr); > > + if (ret) > > + return ret; > > + > > + vcpu = reg_attr.vcpu; > > + addr = reg_attr.addr; > > + > > + mutex_lock(&dev->kvm->lock); > > + > > + ret = vgic_init(dev->kvm); > > + if (ret) > > + goto out; > > no, no, please no more auto-init at userspace access time. This code > should instead check vgic_initialized() and return an error to userspace > if not initialized. > > Ok. I wil fix it. It is coming from v2 code. > > > + > > + if (!lock_all_vcpus(dev->kvm)) { > > + ret = -EBUSY; > > + goto out; > > + } > > + > > + switch (attr->group) { > > + case KVM_DEV_ARM_VGIC_GRP_DIST_REGS: > > + tmp32 = *reg; > > why is this assignment not predicated on if (is_write) ? > > also, all this type conversion nonsense is probably unnecessary, see my > comment below. > > > + ret = vgic_v3_dist_uaccess(vcpu, is_write, addr, &tmp32); > > + if (!is_write) > > + *reg = tmp32; > > + break; > > + case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: > > + tmp32 = *reg; > > + ret = vgic_v3_redist_uaccess(vcpu, is_write, addr, &tmp32); > > + if (!is_write) > > + *reg = tmp32; > > + break; > > + default: > > + ret = -EINVAL; > > + break; > > + } > > + > > + unlock_all_vcpus(dev->kvm); > > +out: > > + mutex_unlock(&dev->kvm->lock); > > + return ret; > > +} > > + > > static int vgic_v3_set_attr(struct kvm_device *dev, > > struct kvm_device_attr *attr) > > { > > - return vgic_set_common_attr(dev, attr); > > + int ret; > > + > > + ret = vgic_set_common_attr(dev, attr); > > + if (ret != -ENXIO) > > + return ret; > > + > > + switch (attr->group) { > > + case KVM_DEV_ARM_VGIC_GRP_DIST_REGS: > > + case KVM_DEV_ARM_VGIC_GRP_REDIST_REGS: { > > + u32 __user *uaddr = (u32 __user *)(long)attr->addr; > > + u32 tmp32; > > + u64 reg; > > + > > + if (get_user(tmp32, uaddr)) > > + return -EFAULT; > > + > > + reg = tmp32; > > + return vgic_attr_regs_access_v3(dev, attr, ®, true); > > oh, but wait, you already had a 32-bit value, which you convert into a > 64-bit value, just to convert it back again, to do some extra data > copies? > > I'm really confused as to why this has to be so complicated. > > Why not simply use u32 all the way? > vgic_attr_regs_access_v3() is used for handling both GICD/GICR and SYSREGS. For this reason we convert u32 to 64 and vice versa. To avoid these conversions, I can create separate vgic_attr_regs_access_v3() functions for GICD and SYSREGS.
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