Re: [PATCH v6 24/24] KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES

Christoffer Dall
2017-05-05T14:56:29Z

On Thu, May 04, 2017 at 01:44:44PM +0200, Eric Auger wrote:
> This patch adds a new attribute to GICV3 KVM device
> KVM_DEV_ARM_VGIC_GRP_CTRL group. This allows userspace to
> flush all GICR pending tables into guest RAM.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
> v5 -> v6:
> - fix stored
> - GICR_PEND/PROPBASER_ADDRESS were already introduced
>
> v4 -> v5:
> - move pending table save code/ctrl into VGICv3 instead of ITS
> - remove useless gpa_t cast
> - use the same optimization as in its_sync_lpi_pending_table
>
> v3 -> v4:
> - remove the wrong comment about locking
> - pass kvm struct instead of its handle
> - add comment about restore method
> - remove GITR_PENDABASER.PTZ check
> - continue if target_vcpu == NULL
> - new locking strategy
>
> v1 -> v2:
> - do not care about the 1st KB which should be zeroed according to
> the spec.
> ---
> arch/arm/include/uapi/asm/kvm.h | 1 +
> arch/arm64/include/uapi/asm/kvm.h | 1 +
> include/linux/irqchip/arm-gic-v3.h | 1 +
> virt/kvm/arm/vgic/vgic-kvm-device.c | 20 +++++++++++++++
> virt/kvm/arm/vgic/vgic-v3.c | 51 +++++++++++++++++++++++++++++++++++++
> virt/kvm/arm/vgic/vgic.h | 1 +
> 6 files changed, 75 insertions(+)
>
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index 8e6563c..78fe803 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -202,6 +202,7 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
> #define KVM_DEV_ARM_ITS_SAVE_TABLES 1
> #define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
> +#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
>
> /* KVM_IRQ_LINE irq field index values */
> #define KVM_ARM_IRQ_TYPE_SHIFT 24
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 1e35115..8a3758a 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -222,6 +222,7 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
> #define KVM_DEV_ARM_ITS_SAVE_TABLES 1
> #define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
> +#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
>
> /* Device Control API on vcpu fd */
> #define KVM_ARM_VCPU_PMU_V3_CTRL 0
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index e09e5d7..347d26f 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -186,6 +186,7 @@
> #define GICR_PENDBASER_RaWaWb GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWaWb)
>
> #define GICR_PENDBASER_PTZ BIT_ULL(62)
> +#define GICR_PENDBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 16))
>
> /*
> * Re-Distributor registers, offsets from SGI_base
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 859bfa8..d48743c 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -580,6 +580,24 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
> reg = tmp32;
> return vgic_v3_attr_regs_access(dev, attr, &reg, true);
> }
> + case KVM_DEV_ARM_VGIC_GRP_CTRL: {
> + int ret;
> +
> + switch (attr->attr) {
> + case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> + mutex_lock(&dev->kvm->lock);
> +
> + if (!lock_all_vcpus(dev->kvm)) {
> + mutex_unlock(&dev->kvm->lock);
> + return -EBUSY;
> + }
> + ret = vgic_v3_save_pending_tables(dev->kvm);
> + unlock_all_vcpus(dev->kvm);
> + mutex_unlock(&dev->kvm->lock);
> + return ret;
> + }
> + break;
> + }
> }
> return -ENXIO;
> }
> @@ -658,6 +676,8 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
> switch (attr->attr) {
> case KVM_DEV_ARM_VGIC_CTRL_INIT:
> return 0;
> + case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> + return 0;
> }
> }
> return -ENXIO;
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index 0d753ae..6ff6510 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -296,6 +296,57 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
> return 0;
> }
>
> +/**
> + * vgic_its_save_pending_tables - Save the pending tables into guest RAM
> + * kvm lock and all vcpu lock must be held
> + */
> +int vgic_v3_save_pending_tables(struct kvm *kvm)
> +{
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + int last_byte_offset = -1;
> + struct vgic_irq *irq;
> + int ret;
> +
> + list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> + int byte_offset, bit_nr;
> + struct kvm_vcpu *vcpu;
> + gpa_t pendbase, ptr;
> + bool stored;
> + u8 val;
> +
> + vcpu = irq->target_vcpu;
> + if (!vcpu)
> + continue;
> +
> + pendbase = GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> +
> + byte_offset = irq->intid / BITS_PER_BYTE;
> + bit_nr = irq->intid % BITS_PER_BYTE;
> + ptr = pendbase + byte_offset;
> +
> + if (byte_offset != last_byte_offset) {
> + ret = kvm_read_guest(kvm, ptr, &val, 1);
> + if (ret)
> + return ret;
> + last_byte_offset = byte_offset;
> + }
> +
> + stored = val & (1U << bit_nr);
> + if (stored == irq->pending_latch)
> + continue;
> +
> + if (irq->pending_latch)
> + val |= 1 << bit_nr;
> + else
> + val &= ~(1 << bit_nr);
> +
> + ret = kvm_write_guest(kvm, ptr, &val, 1);
> + if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> /* check for overlapping regions and for regions crossing the end of memory */
> static bool vgic_v3_check_base(struct kvm *kvm)
> {
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 92a8ca0..8de59a4 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -181,6 +181,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
> int vgic_v3_probe(const struct gic_kvm_info *info);
> int vgic_v3_map_resources(struct kvm *kvm);
> int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
> +int vgic_v3_save_pending_tables(struct kvm *kvm);
> int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
>
> int vgic_register_its_iodevs(struct kvm *kvm);
> --
> 2.5.5
>

Reviewed-by: Christoffer Dall <cdall@linaro.org>