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Re: [Qemu-devel] [RFC v5 5/7] hw/intc/arm_gicv3_its: Implement support f


From: Auger Eric
Subject: Re: [Qemu-devel] [RFC v5 5/7] hw/intc/arm_gicv3_its: Implement support for in-kernel ITS emulation
Date: Wed, 17 Aug 2016 17:59:42 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1

Hi Peter,

On 12/08/2016 16:03, Peter Maydell wrote:
> 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?
The kernel fixes landed in kvmarm/master so I will respin the series
accordingly.

Thanks

Eric
> 
>> +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
> 



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