Re: [RFC PATCH 04/45] KVM: arm/arm64: vgic-new: Add data structure definitions

Andre Przywara
2016-04-06T14:51:38Z

Hej Christoffer,

On 06/04/16 15:46, Christoffer Dall wrote:
> On Wed, Apr 06, 2016 at 03:09:50PM +0100, Andre Przywara wrote:
>>
>>
>> On 06/04/16 14:57, Christoffer Dall wrote:
>>> On Tue, Apr 05, 2016 at 10:10:09PM +0200, Christoffer Dall wrote:
>>>> On Tue, Apr 05, 2016 at 02:34:42PM +0100, Andre Przywara wrote:
>>>>> Hi,
>>>>>
>>>>> On 29/03/16 14:09, Christoffer Dall wrote:
>>>>>> On Fri, Mar 25, 2016 at 02:04:27AM +0000, Andre Przywara wrote:
>>>>>>> From: Christoffer Dall <christoffer.dall@linaro.org>
>>>>>>>
>>>>>>> Add a new header file for the new and improved GIC implementation.
>>>>>>> The big change is that we now have a struct vgic_irq per IRQ instead
>>>>>>> of spreading all the information over various bitmaps.
>>>>>>>
>>>>>>> We include this new header conditionally from within the old header
>>>>>>> file for the time being to avoid touching all the users.
>>>>>>>
>>>>>>> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
>>>>>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>>>>>> ---
>>>>>>> include/kvm/arm_vgic.h | 5 ++
>>>>>>> include/kvm/vgic/vgic.h | 198 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>> 2 files changed, 203 insertions(+)
>>>>>>> create mode 100644 include/kvm/vgic/vgic.h
>>>>>>>
>>>>>>> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
>>>>>>> index 7656a46..db289a2 100644
>>>>>>> --- a/include/kvm/arm_vgic.h
>>>>>>> +++ b/include/kvm/arm_vgic.h
>>>>>>> @@ -19,6 +19,10 @@
>>>>>>> #ifndef __ASM_ARM_KVM_VGIC_H
>>>>>>> #define __ASM_ARM_KVM_VGIC_H
>>>>>>>
>>>>>>> +#ifdef CONFIG_KVM_NEW_VGIC
>>>>>>> +#include <kvm/vgic/vgic.h>
>>>>>>> +#else
>>>>>>> +
>>>>>>> #include <linux/kernel.h>
>>>>>>> #include <linux/kvm.h>
>>>>>>> #include <linux/irqreturn.h>
>>>>>>> @@ -376,4 +380,5 @@ static inline int vgic_v3_probe(struct device_node *vgic_node,
>>>>>>> }
>>>>>>> #endif
>>>>>>>
>>>>>>> +#endif /* old VGIC include */
>>>>>>> #endif
>>>>>>> diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
>>>>>>> new file mode 100644
>>>>>>> index 0000000..659f8b1
>>>>>>> --- /dev/null
>>>>>>> +++ b/include/kvm/vgic/vgic.h
>>>>>>> @@ -0,0 +1,198 @@
>>>>>>> +/*
>>>>>>> + * Copyright (C) 2015, 2016 ARM Ltd.
>>>>>>> + *
>>>>>>> + * 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.
>>>>>>> + *
>>>>>>> + * You should have received a copy of the GNU General Public License
>>>>>>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>>>>>>> + */
>>>>>>> +#ifndef __ASM_ARM_KVM_VGIC_VGIC_H
>>>>>>> +#define __ASM_ARM_KVM_VGIC_VGIC_H
>>>>>>> +
>>>>>>> +#include <linux/kernel.h>
>>>>>>> +#include <linux/kvm.h>
>>>>>>> +#include <linux/irqreturn.h>
>>>>>>> +#include <linux/spinlock.h>
>>>>>>> +#include <linux/types.h>
>>>>>>> +#include <kvm/iodev.h>
>>>>>>> +
>>>>>>> +#define VGIC_V3_MAX_CPUS 255
>>>>>>> +#define VGIC_V2_MAX_CPUS 8
>>>>>>> +#define VGIC_NR_IRQS_LEGACY 256
>>>>>>> +#define VGIC_NR_SGIS 16
>>>>>>> +#define VGIC_NR_PPIS 16
>>>>>>> +#define VGIC_NR_PRIVATE_IRQS (VGIC_NR_SGIS + VGIC_NR_PPIS)
>>>>>>> +#define VGIC_MAX_PRIVATE (VGIC_NR_PRIVATE_IRQS - 1)
>>>>>>> +#define VGIC_MAX_SPI 1019
>>>>>>> +#define VGIC_MAX_RESERVED 1023
>>>>>>> +#define VGIC_MIN_LPI 8192
>>>>>>> +
>>>>>>> +enum vgic_type {
>>>>>>> + VGIC_V2, /* Good ol' GICv2 */
>>>>>>> + VGIC_V3, /* New fancy GICv3 */
>>>>>>> +};
>>>>>>> +
>>>>>>> +/* same for all guests, as depending only on the _host's_ GIC model */
>>>>>>> +struct vgic_global {
>>>>>>> + /* type of the host GIC */
>>>>>>> + enum vgic_type type;
>>>>>>> +
>>>>>>> + /* Physical address of vgic virtual cpu interface */
>>>>>>> + phys_addr_t vcpu_base;
>>>>>>> +
>>>>>>> + /* virtual control interface mapping */
>>>>>>> + void __iomem *vctrl_base;
>>>>>>> +
>>>>>>> + /* Number of implemented list registers */
>>>>>>> + int nr_lr;
>>>>>>> +
>>>>>>> + /* Maintenance IRQ number */
>>>>>>> + unsigned int maint_irq;
>>>>>>> +
>>>>>>> + /* maximum number of VCPUs allowed (GICv2 limits us to 8) */
>>>>>>> + int max_gic_vcpus;
>>>>>>> +
>>>>>>> + /* Only needed for the legacy KVM_CREATE_IRQCHIP */
>>>>>>> + bool can_emulate_gicv2;
>>>>>>> +};
>>>>>>> +
>>>>>>> +extern struct vgic_global kvm_vgic_global_state;
>>>>>>> +
>>>>>>> +#define VGIC_V2_MAX_LRS (1 << 6)
>>>>>>> +#define VGIC_V3_MAX_LRS 16
>>>>>>> +#define VGIC_V3_LR_INDEX(lr) (VGIC_V3_MAX_LRS - 1 - lr)
>>>>>>> +
>>>>>>> +enum vgic_irq_config {
>>>>>>> + VGIC_CONFIG_EDGE = 0,
>>>>>>> + VGIC_CONFIG_LEVEL
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct vgic_irq {
>>>>>>> + spinlock_t irq_lock; /* Protects the content of the struct */
>>>>>>> + struct list_head ap_list;
>>>>>>> +
>>>>>>> + struct kvm_vcpu *vcpu; /* SGIs and PPIs: The VCPU
>>>>>>> + * SPIs and LPIs: The VCPU whose ap_list
>>>>>>> + * on which this is queued.
>>>>>>> + */
>>>>>>> +
>>>>>>> + struct kvm_vcpu *target_vcpu; /* The VCPU that this interrupt should
>>>>>>> + * be send to, as a result of the
>>>>>>> + * targets reg (v2) or the
>>>>>>> + * affinity reg (v3).
>>>>>>> + */
>>>>>>> +
>>>>>>> + u32 intid; /* Guest visible INTID */
>>>>>>> + bool pending;
>>>>>>> + bool line_level; /* Level only */
>>>>>>> + bool soft_pending; /* Level only */
>>>>>>> + bool active; /* not used for LPIs */
>>>>>>> + bool enabled;
>>>>>>> + bool hw; /* Tied to HW IRQ */
>>>>>>> + u32 hwintid; /* HW INTID number */
>>>>>>> + union {
>>>>>>> + u8 targets; /* GICv2 target VCPUs mask */
>>>>>>> + u32 mpidr; /* GICv3 target VCPU */
>>>>>>> + };
>>>>>>> + u8 source; /* GICv2 SGIs only */
>>>>>>> + u8 priority;
>>>>>>> + enum vgic_irq_config config; /* Level or edge */
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct vgic_dist {
>>>>>>> + bool in_kernel;
>>>>>>> + bool ready;
>>>>>>> +
>>>>>>> + /* vGIC model the kernel emulates for the guest (GICv2 or GICv3) */
>>>>>>> + u32 vgic_model;
>>>>>>> +
>>>>>>> + int nr_spis;
>>>>>>> +
>>>>>>> + /* TODO: Consider moving to global state */
>>>>>>> + /* Virtual control interface mapping */
>>>>>>> + void __iomem *vctrl_base;
>>>>>>> +
>>>>>>> + /* base addresses in guest physical address space: */
>>>>>>> + gpa_t vgic_dist_base; /* distributor */
>>>>>>> + union {
>>>>>>> + /* either a GICv2 CPU interface */
>>>>>>> + gpa_t vgic_cpu_base;
>>>>>>> + /* or a number of GICv3 redistributor regions */
>>>>>>> + gpa_t vgic_redist_base;
>>>>>>> + };
>>>>>>> +
>>>>>>> + /* distributor enabled */
>>>>>>> + u32 enabled;
>>>>>>> +
>>>>>>> + struct vgic_irq *spis;
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct vgic_v2_cpu_if {
>>>>>>> + u32 vgic_hcr;
>>>>>>> + u32 vgic_vmcr;
>>>>>>> + u32 vgic_misr; /* Saved only */
>>>>>>> + u64 vgic_eisr; /* Saved only */
>>>>>>> + u64 vgic_elrsr; /* Saved only */
>>>>>>> + u32 vgic_apr;
>>>>>>> + u32 vgic_lr[VGIC_V2_MAX_LRS];
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct vgic_v3_cpu_if {
>>>>>>> +#ifdef CONFIG_KVM_ARM_VGIC_V3
>>>>>>> + u32 vgic_hcr;
>>>>>>> + u32 vgic_vmcr;
>>>>>>> + u32 vgic_sre; /* Restored only, change ignored */
>>>>>>> + u32 vgic_misr; /* Saved only */
>>>>>>> + u32 vgic_eisr; /* Saved only */
>>>>>>> + u32 vgic_elrsr; /* Saved only */
>>>>>>> + u32 vgic_ap0r[4];
>>>>>>> + u32 vgic_ap1r[4];
>>>>>>> + u64 vgic_lr[VGIC_V3_MAX_LRS];
>>>>>>> +#endif
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct vgic_cpu {
>>>>>>> + /* CPU vif control registers for world switch */
>>>>>>> + union {
>>>>>>> + struct vgic_v2_cpu_if vgic_v2;
>>>>>>> + struct vgic_v3_cpu_if vgic_v3;
>>>>>>> + };
>>>>>>> +
>>>>>>> + /* TODO: Move nr_lr to a global state */
>>>>>>
>>>>>> what is our current plan and status about this TODO?
>>>>>
>>>>> The point is that the current HYP code is accessing this field. We do
>>>>> have this field in the current "global" struct vgic_params there as
>>>>> well, but this struct is (more or less) private to vgic-v2.c, so not
>>>>> easily accessible from virt/kvm/arm/hyp/*.c.
>>>>> So I suggest we keep this in here for the time being and eventually
>>>>> remove it (and rework the save/restore code) once we get rid of the old
>>>>> VGIC code.
>>>>>
>>>> Hmmm, I haven't tried it, but I don't understand why moving it now is
>>>> difficult. I'd really like to avoid having a bunch of todo's lingering
>>>> around and having duplicated state in the new code.
>>>>
>>>> I think I noticed a number of places in this patch series which refers
>>>> tot he vgic_cpu->nr_lr instead of the global place already...
>>>>
>>> So I wrote a patch for this and it doesn't really look that bad. I'll
>>> send it as part of a little prerequisite series later.
>>
>> I just fixed it as well - the private new VGIC part is trivial indeed.
>> But how did you solve the reference to the vgic_cpu.nr_lr in
>> virt/kvm/arm/hyp/vgic-v2-sr.c? With #ifdef .. #else? Or passing in the
>> number as in vgic-v3-sr.c?
>>
>
> I sent you a couple of patches as I said I would.
>
> I just used an extern with the kern_hyp_va() macro trickery applied.
> Not the prettiest thing in the world, but hey. It should serve just
> fine for moving on with this, and then we can worry about the finesses
> as the vgic series progresses.

Agreed, thanks for those patches. I think I will just cherry-pick 2/3
and 3/3.
I am tempted to post my version of what you did in 1/3, which goes a bit
further and avoids some copying between different kind of structs.

Cheers,
Andre.