[PATCH v3 32/55] KVM: arm/arm64: vgic-new: Add GICv3 MMIO handling framework
Andre Przywara
andre.przywara at arm.com
Thu May 12 03:52:58 PDT 2016
Hi,
On 12/05/16 11:26, Christoffer Dall wrote:
> On Fri, May 06, 2016 at 11:45:45AM +0100, Andre Przywara wrote:
>> Create a new file called vgic-mmio-v3.c and describe the GICv3
>> distributor and redistributor registers there.
>> This adds a special macro to deal with the split of SGI/PPI in the
>> redistributor and SPIs in the distributor, which allows us to reuse
>> the existing GICv2 handlers for those registers which are compatible.
>> Also we provide a function to deal with the registration of the two
>> separate redistributor frames per VCPU.
>>
>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>> Reviewed-by: Eric Auger <eric.auger at linaro.org>
>> ---
>> Changelog RFC..v1:
>> - adapt to new MMIO registration approach:
>> register one device for the distributor and two for each VCPU
>> - implement special handling for private interrupts
>> - remove empty stub functions
>> - make IGROUPR return RAO
>>
>> Changelog v1 .. v2:
>> - adapt to new framework, introduce vgic-mmio-v3.c
>> - remove userland register access functions (for now)
>> - precompute .len when describing a VGIC register
>> - add missed pointer incrementation on registering redist regions
>> - replace _nyi stub functions with raz/wi versions
>>
>> Changelog v2 .. v3:
>> - replace inclusion of kvm/vgic/vgic.h with kvm/arm_vgic.h
>> - add prototype and stub code for vgic_register_redist_iodevs
>> - rename register struct variables _rdbase_ and _sgibase_
>>
>> virt/kvm/arm/vgic/vgic-mmio-v3.c | 191 +++++++++++++++++++++++++++++++++++++++
>> virt/kvm/arm/vgic/vgic-mmio.c | 5 +
>> virt/kvm/arm/vgic/vgic-mmio.h | 2 +
>> virt/kvm/arm/vgic/vgic.h | 7 ++
>> 4 files changed, 205 insertions(+)
>> create mode 100644 virt/kvm/arm/vgic/vgic-mmio-v3.c
>>
>> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
>> new file mode 100644
>> index 0000000..06c7ec5
>> --- /dev/null
>> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
>> @@ -0,0 +1,191 @@
>> +/*
>> + * VGICv3 MMIO handling functions
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program 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 General Public License for more details.
>> + */
>> +
>> +#include <linux/irqchip/arm-gic-v3.h>
>> +#include <linux/kvm.h>
>> +#include <linux/kvm_host.h>
>> +#include <kvm/iodev.h>
>> +#include <kvm/arm_vgic.h>
>> +
>> +#include <asm/kvm_emulate.h>
>> +
>> +#include "vgic.h"
>> +#include "vgic-mmio.h"
>> +
>> +/*
>> + * The GICv3 per-IRQ registers are split to control PPIs and SGIs in the
>> + * redistributors, while SPIs are covered by registers in the distributor
>> + * block. Trying to set private IRQs in this block gets ignored.
>> + * We take some special care here to fix the calculation of the register
>> + * offset.
>> + */
>> +#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, read_ops, write_ops, bpi) \
>> + { \
>> + .reg_offset = off, \
>> + .bits_per_irq = bpi, \
>> + .len = (bpi * VGIC_NR_PRIVATE_IRQS) / 8, \
>> + .read = vgic_mmio_read_raz, \
>> + .write = vgic_mmio_write_wi, \
>> + }, { \
>> + .reg_offset = off + (bpi * VGIC_NR_PRIVATE_IRQS) / 8, \
>> + .bits_per_irq = bpi, \
>> + .len = (bpi * (1024 - VGIC_NR_PRIVATE_IRQS)) / 8, \
>> + .read = read_ops, \
>> + .write = write_ops, \
>> + }
>> +
>> +static const struct vgic_register_region vgic_v3_dist_registers[] = {
>> + REGISTER_DESC_WITH_LENGTH(GICD_CTLR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 16),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGROUPR,
>> + vgic_mmio_read_rao, vgic_mmio_write_wi, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISENABLER,
>> + vgic_mmio_read_enable, vgic_mmio_write_senable, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICENABLER,
>> + vgic_mmio_read_enable, vgic_mmio_write_cenable, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISPENDR,
>> + vgic_mmio_read_pending, vgic_mmio_write_spending, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICPENDR,
>> + vgic_mmio_read_pending, vgic_mmio_write_cpending, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISACTIVER,
>> + vgic_mmio_read_active, vgic_mmio_write_sactive, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICACTIVER,
>> + vgic_mmio_read_active, vgic_mmio_write_cactive, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IPRIORITYR,
>> + vgic_mmio_read_priority, vgic_mmio_write_priority, 8),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ITARGETSR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICFGR,
>> + vgic_mmio_read_config, vgic_mmio_write_config, 2),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGRPMODR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 1),
>> + REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IROUTER,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 64),
>> + REGISTER_DESC_WITH_LENGTH(GICD_IDREGS,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 48),
>> +};
>> +
>> +static const struct vgic_register_region vgic_v3_rdbase_registers[] = {
>> + REGISTER_DESC_WITH_LENGTH(GICR_CTLR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_IIDR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_TYPER,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> + REGISTER_DESC_WITH_LENGTH(GICR_PROPBASER,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> + REGISTER_DESC_WITH_LENGTH(GICR_PENDBASER,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 8),
>> + REGISTER_DESC_WITH_LENGTH(GICR_IDREGS,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 48),
>> +};
>> +
>> +static const struct vgic_register_region vgic_v3_sgibase_registers[] = {
>> + REGISTER_DESC_WITH_LENGTH(GICR_IGROUPR0,
>> + vgic_mmio_read_rao, vgic_mmio_write_wi, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ISENABLER0,
>> + vgic_mmio_read_enable, vgic_mmio_write_senable, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ICENABLER0,
>> + vgic_mmio_read_enable, vgic_mmio_write_cenable, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ISPENDR0,
>> + vgic_mmio_read_pending, vgic_mmio_write_spending, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ICPENDR0,
>> + vgic_mmio_read_pending, vgic_mmio_write_cpending, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ISACTIVER0,
>> + vgic_mmio_read_active, vgic_mmio_write_sactive, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ICACTIVER0,
>> + vgic_mmio_read_active, vgic_mmio_write_cactive, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_IPRIORITYR0,
>> + vgic_mmio_read_priority, vgic_mmio_write_priority, 32),
>> + REGISTER_DESC_WITH_LENGTH(GICR_ICFGR0,
>> + vgic_mmio_read_config, vgic_mmio_write_config, 8),
>> + REGISTER_DESC_WITH_LENGTH(GICR_IGRPMODR0,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> + REGISTER_DESC_WITH_LENGTH(GICR_NSACR,
>> + vgic_mmio_read_raz, vgic_mmio_write_wi, 4),
>> +};
>> +
>> +unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev)
>> +{
>> + dev->regions = vgic_v3_dist_registers;
>> + dev->nr_regions = ARRAY_SIZE(vgic_v3_dist_registers);
>> +
>> + kvm_iodevice_init(&dev->dev, &kvm_io_gic_ops);
>> +
>> + return SZ_64K;
>> +}
>> +
>> +int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
>> +{
>> + int nr_vcpus = atomic_read(&kvm->online_vcpus);
>> + struct kvm_vcpu *vcpu;
>> + struct vgic_io_device *devices, *device;
>> + int c, ret = 0;
>> +
>> + devices = kmalloc(sizeof(struct vgic_io_device) * nr_vcpus * 2,
>> + GFP_KERNEL);
>> + if (!devices)
>> + return -ENOMEM;
>> +
>> + device = devices;
>> + kvm_for_each_vcpu(c, vcpu, kvm) {
>> + kvm_iodevice_init(&device->dev, &kvm_io_gic_ops);
>> + device->base_addr = redist_base_address;
>> + device->regions = vgic_v3_rdbase_registers;
>> + device->nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers);
>> + device->redist_vcpu = vcpu;
>> +
>> + mutex_lock(&kvm->slots_lock);
>> + ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS,
>> + redist_base_address,
>> + SZ_64K, &device->dev);
>> + mutex_unlock(&kvm->slots_lock);
>> +
>> + if (ret)
>> + break;
>> +
>> + device++;
>> + kvm_iodevice_init(&device->dev, &kvm_io_gic_ops);
>> + device->base_addr = redist_base_address + SZ_64K;
>> + device->regions = vgic_v3_sgibase_registers;
>> + device->nr_regions = ARRAY_SIZE(vgic_v3_sgibase_registers);
>> + device->redist_vcpu = vcpu;
>> +
>> + mutex_lock(&kvm->slots_lock);
>> + ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS,
>> + redist_base_address + SZ_64K,
>> + SZ_64K, &device->dev);
>> + mutex_unlock(&kvm->slots_lock);
>> + if (ret) {
>> + kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
>> + &devices[c * 2].dev);
>> + break;
>> + }
>> + device++;
>> + redist_base_address += 2 * SZ_64K;
>
> while I think this whole thing is actually correct, I think it could
> have been much more clear by, in the beginning of the loop doing:
>
> gpa_t rd_base = redist_base_address + c * SZ_64K * 2;
> gpa_t sgi_base = rd_base + SZ_64K;
> struct vgic_io_device *rd_dev = &devices[c];
> struct vgic_io_device *sgi_dev = &devices[c + 1];
>
> and then referring directly to these variables.
Yeah, looks useful, not sure we want to change it last minute though.
>> + }
>> +
>> + if (ret) {
>> + for (c--; c >= 0; c--) {
>
> holy dark mother of all that's evil; I think this is correct.
>
>> + kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
>> + &devices[c * 2].dev);
>> + kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
>> + &devices[c * 2 + 1].dev);
>
> do we really need this though? Can't we just rely on KVM to tear down
> thew whole bus infrastructure as we're returning an error anyway?
I haven't checked if this is really necessary, but this missing teardown
was mentioned multiple times in previous reviews, so I just did it.
We can remove it once we have proven that it's pointless later.
> (have you looked at what the unregister_dev function does, it's full of
> kmallocs and other fun stuff).
TBH, this whole kvm_io_bus framework is really weird (I think
registering a new region copies every thing it had before) and designed
for the x86 use case. But it shouldn't be this series which fixes this.
Cheers,
Andre.
>
> Thanks,
> -Christoffer
>
>> + }
>> + kfree(devices);
>> + } else {
>> + kvm->arch.vgic.redist_iodevs = devices;
>> + }
>> +
>> + return ret;
>> +}
>> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
>> index 19fed56..d1b88d2 100644
>> --- a/virt/kvm/arm/vgic/vgic-mmio.c
>> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
>> @@ -502,6 +502,11 @@ int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
>> case VGIC_V2:
>> len = vgic_v2_init_dist_iodev(io_device);
>> break;
>> +#ifdef CONFIG_KVM_ARM_VGIC_V3
>> + case VGIC_V3:
>> + len = vgic_v3_init_dist_iodev(io_device);
>> + break;
>> +#endif
>> default:
>> BUG_ON(1);
>> }
>> diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
>> index 884eb71..3585ac6 100644
>> --- a/virt/kvm/arm/vgic/vgic-mmio.h
>> +++ b/virt/kvm/arm/vgic/vgic-mmio.h
>> @@ -123,4 +123,6 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
>>
>> unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
>>
>> +unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
>> +
>> #endif
>> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
>> index cf62015..39a8a65 100644
>> --- a/virt/kvm/arm/vgic/vgic.h
>> +++ b/virt/kvm/arm/vgic/vgic.h
>> @@ -40,6 +40,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu);
>> void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
>> void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr);
>> void vgic_v3_set_underflow(struct kvm_vcpu *vcpu);
>> +int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
>> #else
>> static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
>> {
>> @@ -61,6 +62,12 @@ static inline void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr)
>> static inline void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
>> {
>> }
>> +
>> +static inline int vgic_register_redist_iodevs(struct kvm *kvm,
>> + gpa_t dist_base_address)
>> +{
>> + return -ENODEV;
>> +}
>> #endif
>>
>> #endif
>> --
>> 2.7.3
>>
>
>
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