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List: kvm
Subject: Re: [RFC PATCH 3/5] KVM: ARM VGIC add kvm_io_bus_ frontend
From: Nikolay Nikolaev <n.nikolaev () virtualopensystems ! com>
Date: 2014-11-29 13:58:50
Message-ID: CADDJ2=OLgHhNwLrswfHAVYhh+4FEAxN=B5y4UFJahWkkkni4Tg () mail ! gmail ! com
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On Sat, Nov 29, 2014 at 9:14 AM, Shannon Zhao <zhaoshenglong@huawei.com> wrote:
> On 2014/11/25 5:26, Nikolay Nikolaev wrote:
> > In io_mem_abort remove the call to vgic_handle_mmio. The target is to have
> > a single MMIO handling path - that is through the kvm_io_bus_ API.
> >
> > Register a kvm_io_device in kvm_vgic_init on the whole vGIC MMIO region.
> > Both read and write calls are redirected to vgic_io_dev_access where
> > kvm_exit_mmio is composed to pass it to vm_ops.handle_mmio.
> >
> >
> > Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
> > ---
> > arch/arm/kvm/mmio.c | 3 --
> > include/kvm/arm_vgic.h | 3 +-
> > virt/kvm/arm/vgic.c | 88 ++++++++++++++++++++++++++++++++++++++++--------
> > 3 files changed, 74 insertions(+), 20 deletions(-)
> >
> > diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
> > index 81230da..1c44a2b 100644
> > --- a/arch/arm/kvm/mmio.c
> > +++ b/arch/arm/kvm/mmio.c
> > @@ -227,9 +227,6 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
> > if (mmio.is_write)
> > mmio_write_buf(mmio.data, mmio.len, data);
> >
> > - if (vgic_handle_mmio(vcpu, run, &mmio))
> > - return 1;
> > -
> > if (handle_kernel_mmio(vcpu, run, &mmio))
> > return 1;
> >
> > diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> > index e452ef7..d9b7d2a 100644
> > --- a/include/kvm/arm_vgic.h
> > +++ b/include/kvm/arm_vgic.h
> > @@ -233,6 +233,7 @@ struct vgic_dist {
> > unsigned long *irq_pending_on_cpu;
> >
> > struct vgic_vm_ops vm_ops;
> > + struct kvm_io_device *io_dev;
> > #endif
> > };
> >
> > @@ -307,8 +308,6 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned \
> > int irq_num, bool level);
> > void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
> > int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
> > -bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
> > - struct kvm_exit_mmio *mmio);
> >
> > #define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel))
> > #define vgic_initialized(k) ((k)->arch.vgic.ready)
> > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> > index 1213da5..3da1115 100644
> > --- a/virt/kvm/arm/vgic.c
> > +++ b/virt/kvm/arm/vgic.c
> > @@ -31,6 +31,9 @@
> > #include <asm/kvm_emulate.h>
> > #include <asm/kvm_arm.h>
> > #include <asm/kvm_mmu.h>
> > +#include <asm/kvm.h>
> > +
> > +#include "iodev.h"
> >
> > /*
> > * How the whole thing works (courtesy of Christoffer Dall):
> > @@ -775,28 +778,81 @@ bool vgic_handle_mmio_range(struct kvm_vcpu *vcpu, struct \
> > kvm_run *run, return true;
> > }
> >
> > -/**
> > - * vgic_handle_mmio - handle an in-kernel MMIO access for the GIC emulation
> > - * @vcpu: pointer to the vcpu performing the access
> > - * @run: pointer to the kvm_run structure
> > - * @mmio: pointer to the data describing the access
> > - *
> > - * returns true if the MMIO access has been performed in kernel space,
> > - * and false if it needs to be emulated in user space.
> > - * Calls the actual handling routine for the selected VGIC model.
> > - */
> > -bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
> > - struct kvm_exit_mmio *mmio)
> > +static int vgic_io_dev_access(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
> > + gpa_t addr, int len, void *val, bool is_write)
> > {
> > - if (!irqchip_in_kernel(vcpu->kvm))
> > - return false;
> > + struct kvm_exit_mmio mmio;
> > + bool ret;
> > +
> > + mmio = (struct kvm_exit_mmio) {
> > + .phys_addr = addr,
> > + .len = len,
> > + .is_write = is_write,
> > + };
> > +
> > + if (is_write)
> > + memcpy(mmio.data, val, len);
> >
> > /*
> > * This will currently call either vgic_v2_handle_mmio() or
> > * vgic_v3_handle_mmio(), which in turn will call
> > * vgic_handle_mmio_range() defined above.
> > */
> > - return vcpu->kvm->arch.vgic.vm_ops.handle_mmio(vcpu, run, mmio);
> > + ret = vcpu->kvm->arch.vgic.vm_ops.handle_mmio(vcpu, vcpu->run, &mmio);
> > +
> > + if (!is_write)
> > + memcpy(val, mmio.data, len);
> > +
> > + return ret ? 0 : 1;
> > +}
> > +
> > +static int vgic_io_dev_read(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
> > + gpa_t addr, int len, void *val)
> > +{
> > + return vgic_io_dev_access(vcpu, this, addr, len, val, false);
> > +}
> > +
> > +static int vgic_io_dev_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
> > + gpa_t addr, int len, const void *val)
> > +{
> > + return vgic_io_dev_access(vcpu, this, addr, len, (void *)val, true);
> > +}
> > +
> > +static const struct kvm_io_device_ops vgic_io_dev_ops = {
> > + .read = vgic_io_dev_read,
> > + .write = vgic_io_dev_write,
> > +};
> > +
> > +static int vgic_register_kvm_io_dev(struct kvm *kvm)
> > +{
> > + struct kvm_io_device *dev;
> > + int ret;
> > +
> > + struct vgic_dist *dist = &kvm->arch.vgic;
> > + unsigned long base = dist->vgic_dist_base;
> > +
> > + dev = kzalloc(sizeof(struct kvm_io_device), GFP_KERNEL);
> > + if (!dev)
> > + return -ENOMEM;
> > +
> > + kvm_iodevice_init(dev, &vgic_io_dev_ops);
> > +
> > + mutex_lock(&kvm->slots_lock);
> > +
> > + ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS,
> > + base, KVM_VGIC_V2_DIST_SIZE, dev);
>
> Should we consider GICv3? I think if applying this patch, it can not run well while \
> creating a vGICv3 for guest.
Agree. Christofer also pointed this out. Will select the dist size
depending on the vgic_model.
Thanks.
Nikolay Nikolay
>
> Thanks,
> Shannon
> > + if (ret < 0)
> > + goto out_free_dev;
> > + mutex_unlock(&kvm->slots_lock);
> > +
> > + kvm->arch.vgic.io_dev = dev;
> > +
> > + return 0;
> > +
> > +out_free_dev:
> > + mutex_unlock(&kvm->slots_lock);
> > + kfree(dev);
> > + return ret;
> > }
> >
> > static int vgic_nr_shared_irqs(struct vgic_dist *dist)
> > @@ -1545,6 +1601,8 @@ int kvm_vgic_init(struct kvm *kvm)
> >
> > mutex_lock(&kvm->lock);
> >
> > + vgic_register_kvm_io_dev(kvm);
> > +
> > if (vgic_initialized(kvm))
> > goto out;
> >
> >
> > _______________________________________________
> > kvmarm mailing list
> > kvmarm@lists.cs.columbia.edu
> > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
> >
> > .
> >
>
>
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