Re: [Qemu-devel] [RFC v5 5/7] hw/intc/arm_gicv3_its: Implement support for in-kernel ITS emulation

[Peter Maydell]

On 2 August 2016 at 19:07, Eric Auger <address@hidden> wrote:
> From: Pavel Fedin <address@hidden>
>
> The ITS control frame is in-kernel emulated while accesses to the
> GITS_TRANSLATER are mediated through the KVM_SIGNAL_MSI ioctl (MSI
> direct MSI injection advertised by the CAP_SIGNAL_MSI capability)
>
> the kvm_gsi_direct_mapping is explicitly set to false to emphasize the
> difference with GICv2M. Direct mapping cannot work with ITS since
> the content of the MSI data is not the target interrupt ID but an
> eventd id.
>
> GSI routing is advertised (kvm_gsi_routing_allowed) as well as
> msi/irqfd signaling (kvm_msi_via_irqfd_allowed).
>
> Signed-off-by: Pavel Fedin <address@hidden>
> Signed-off-by: Eric Auger <address@hidden>
>
> ---
>
> v3 -> v4:
> - include "qemu/osdep.h" and  "qapi/error.h"
> - rename KVM_VGIC_V3_ADDR_TYPE_ITS into KVM_VGIC_ITS_ADDR_TYPE
> - reword commit message
> - change kvm_msi_via_irqfd_allowed definition (attached to irqfd dynamic
>   availability + MSI controller availability)
> - create the ITS KVM device (previously abstracted by the GICv3 KVM device)
> - init sequence changed
> - absolute GITS_TRANSLATER GPA stored
> ---
>  hw/intc/Makefile.objs       |   1 +
>  hw/intc/arm_gicv3_its_kvm.c | 145 
> ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 146 insertions(+)
>  create mode 100644 hw/intc/arm_gicv3_its_kvm.c
>
> diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
> index 23a39f7..9cca280 100644
> --- a/hw/intc/Makefile.objs
> +++ b/hw/intc/Makefile.objs
> @@ -22,6 +22,7 @@ common-obj-$(CONFIG_OPENPIC) += openpic.o
>  obj-$(CONFIG_APIC) += apic.o apic_common.o
>  obj-$(CONFIG_ARM_GIC_KVM) += arm_gic_kvm.o
>  obj-$(call land,$(CONFIG_ARM_GIC_KVM),$(TARGET_AARCH64)) += arm_gicv3_kvm.o
> +obj-$(call land,$(CONFIG_ARM_GIC_KVM),$(TARGET_AARCH64)) += 
> arm_gicv3_its_kvm.o
>  obj-$(CONFIG_STELLARIS) += armv7m_nvic.o
>  obj-$(CONFIG_EXYNOS4) += exynos4210_gic.o exynos4210_combiner.o
>  obj-$(CONFIG_GRLIB) += grlib_irqmp.o
> diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
> new file mode 100644
> index 0000000..b6d92aa
> --- /dev/null
> +++ b/hw/intc/arm_gicv3_its_kvm.c
> @@ -0,0 +1,145 @@
> +/*
> + * KVM-based ITS implementation for a GICv3-based system
> + *
> + * Copyright (c) 2015 Samsung Electronics Co., Ltd.
> + * Written by Pavel Fedin <address@hidden>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see 
> <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "hw/intc/arm_gicv3_its_common.h"
> +#include "sysemu/sysemu.h"
> +#include "sysemu/kvm.h"
> +#include "kvm_arm.h"
> +
> +#define TYPE_KVM_ARM_ITS "arm-its-kvm"
> +#define KVM_ARM_ITS(obj) OBJECT_CHECK(GICv3ITSState, (obj), TYPE_KVM_ARM_ITS)
> +
> +static int kvm_its_send_msi(GICv3ITSState *s, uint32_t value, uint16_t devid)
> +{
> +    struct kvm_msi msi;
> +
> +    msi.address_lo = s->gits_translater_gpa & 0xFFFFFFFFULL;
> +    msi.address_hi = s->gits_translater_gpa >> 32;

extract64() might be preferable?

> +    msi.data = value;
> +    msi.flags = KVM_MSI_VALID_DEVID;
> +    msi.devid = devid;
> +    memset(msi.pad, 0, sizeof(msi.pad));
> +
> +    return kvm_vm_ioctl(kvm_state, KVM_SIGNAL_MSI, &msi);
> +}
> +
> +typedef struct ItsInitNotifierParams {
> +    Notifier notifier;
> +    GICv3ITSState *s;
> +} ItsInitNotifierParams;
> +
> +/**
> + *
> + * We currently do not use kvm_arm_register_device to provide
> + * the kernel with the vITS control frame base address since the
> + * KVM_DEV_ARM_VGIC_CTRL_INIT init MUST be called after the
> + * KVM_ARM_SET_DEVICE_ADDR and the kvm_arm_register_device
> + * infra does not allow this.
> + */

I thought we'd fixed the kernel API so we didn't need to
have this workaround?

> +static void its_notify(Notifier *notifier, void *data)
> +{
> +    ItsInitNotifierParams *p = DO_UPCAST(ItsInitNotifierParams,
> +                                         notifier, notifier);
> +    GICv3ITSState *s = p->s;
> +    MemoryRegion *mr = &s->iomem_its_cntrl;
> +    MemoryRegionSection mrs;
> +    struct kvm_device_attr attr;
> +    uint64_t addr;
> +    int ret;
> +
> +    mrs = memory_region_find(mr, 0, 1);
> +    addr = mrs.offset_within_address_space;
> +
> +    attr.flags = 0;
> +    attr.group = KVM_DEV_ARM_VGIC_GRP_ADDR;
> +    attr.attr = KVM_VGIC_ITS_ADDR_TYPE;
> +    attr.addr =  (uintptr_t)&addr;
> +
> +    s->gits_translater_gpa = addr + ITS_CONTROL_SIZE + 0x40;
> +
> +    ret = kvm_device_ioctl(s->dev_fd, KVM_SET_DEVICE_ATTR, attr);
> +    if (ret) {
> +        error_setg_errno(&error_fatal, -ret,
> +                         "not able to set base address for vITS ctrl frame");
> +    }
> +
> +    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
> +                      KVM_DEV_ARM_VGIC_CTRL_INIT, NULL, true);
> +}

thanks
-- PMM