Re: [PATCH v2 06/10] RISC-V: KVM: Implement device interface for AIA irqchip

From: Anup Patel
Date: Thu Jun 15 2023 - 02:25:41 EST

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In reply to: Yong-Xuan Wang: "Re: [PATCH v2 06/10] RISC-V: KVM: Implement device interface for AIA irqchip"
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On Thu, Jun 15, 2023 at 11:03 AM Yong-Xuan Wang
<yongxuan.wang@xxxxxxxxxx> wrote:
>
> Hi Anup,
>
> On Mon, Jun 12, 2023 at 1:41 PM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
> >
> > We implement KVM device interface for in-kernel AIA irqchip so that
> > user-space can use KVM device ioctls to create, configure, and destroy
> > in-kernel AIA irqchip.
> >
> > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > ---
> > arch/riscv/include/asm/kvm_aia.h | 132 +++++--
> > arch/riscv/include/uapi/asm/kvm.h | 45 +++
> > arch/riscv/kvm/Makefile | 1 +
> > arch/riscv/kvm/aia.c | 11 +
> > arch/riscv/kvm/aia_device.c | 622 ++++++++++++++++++++++++++++++
> > include/uapi/linux/kvm.h | 2 +
> > 6 files changed, 771 insertions(+), 42 deletions(-)
> > create mode 100644 arch/riscv/kvm/aia_device.c
> >
> > diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h
> > index 3bc0a0e47a15..a1281ebc9b92 100644
> > --- a/arch/riscv/include/asm/kvm_aia.h
> > +++ b/arch/riscv/include/asm/kvm_aia.h
> > @@ -20,6 +20,33 @@ struct kvm_aia {
> >
> > /* In-kernel irqchip initialized */
> > bool initialized;
> > +
> > + /* Virtualization mode (Emulation, HW Accelerated, or Auto) */
> > + u32 mode;
> > +
> > + /* Number of MSIs */
> > + u32 nr_ids;
> > +
> > + /* Number of wired IRQs */
> > + u32 nr_sources;
> > +
> > + /* Number of group bits in IMSIC address */
> > + u32 nr_group_bits;
> > +
> > + /* Position of group bits in IMSIC address */
> > + u32 nr_group_shift;
> > +
> > + /* Number of hart bits in IMSIC address */
> > + u32 nr_hart_bits;
> > +
> > + /* Number of guest bits in IMSIC address */
> > + u32 nr_guest_bits;
> > +
> > + /* Guest physical address of APLIC */
> > + gpa_t aplic_addr;
> > +
> > + /* Internal state of APLIC */
> > + void *aplic_state;
> > };
> >
> > struct kvm_vcpu_aia_csr {
> > @@ -38,8 +65,19 @@ struct kvm_vcpu_aia {
> >
> > /* CPU AIA CSR context upon Guest VCPU reset */
> > struct kvm_vcpu_aia_csr guest_reset_csr;
> > +
> > + /* Guest physical address of IMSIC for this VCPU */
> > + gpa_t imsic_addr;
> > +
> > + /* HART index of IMSIC extacted from guest physical address */
> > + u32 hart_index;
> > +
> > + /* Internal state of IMSIC for this VCPU */
> > + void *imsic_state;
> > };
> >
> > +#define KVM_RISCV_AIA_UNDEF_ADDR (-1)
> > +
> > #define kvm_riscv_aia_initialized(k) ((k)->arch.aia.initialized)
> >
> > #define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel)
> > @@ -50,10 +88,17 @@ DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available);
> > #define kvm_riscv_aia_available() \
> > static_branch_unlikely(&kvm_riscv_aia_available)
> >
> > +extern struct kvm_device_ops kvm_riscv_aia_device_ops;
> > +
> > static inline void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu)
> > {
> > }
> >
> > +static inline int kvm_riscv_vcpu_aia_imsic_update(struct kvm_vcpu *vcpu)
> > +{
> > + return 1;
> > +}
> > +
> > #define KVM_RISCV_AIA_IMSIC_TOPEI (ISELECT_MASK + 1)
> > static inline int kvm_riscv_vcpu_aia_imsic_rmw(struct kvm_vcpu *vcpu,
> > unsigned long isel,
> > @@ -64,6 +109,41 @@ static inline int kvm_riscv_vcpu_aia_imsic_rmw(struct kvm_vcpu *vcpu,
> > return 0;
> > }
> >
> > +static inline void kvm_riscv_vcpu_aia_imsic_reset(struct kvm_vcpu *vcpu)
> > +{
> > +}
> > +
> > +static inline int kvm_riscv_vcpu_aia_imsic_inject(struct kvm_vcpu *vcpu,
> > + u32 guest_index, u32 offset,
> > + u32 iid)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline int kvm_riscv_vcpu_aia_imsic_init(struct kvm_vcpu *vcpu)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline void kvm_riscv_vcpu_aia_imsic_cleanup(struct kvm_vcpu *vcpu)
> > +{
> > +}
> > +
> > +static inline int kvm_riscv_aia_aplic_inject(struct kvm *kvm,
> > + u32 source, bool level)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline int kvm_riscv_aia_aplic_init(struct kvm *kvm)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline void kvm_riscv_aia_aplic_cleanup(struct kvm *kvm)
> > +{
> > +}
> > +
> > #ifdef CONFIG_32BIT
> > void kvm_riscv_vcpu_aia_flush_interrupts(struct kvm_vcpu *vcpu);
> > void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu);
> > @@ -99,50 +179,18 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num,
> > { .base = CSR_SIREG, .count = 1, .func = kvm_riscv_vcpu_aia_rmw_ireg }, \
> > { .base = CSR_STOPEI, .count = 1, .func = kvm_riscv_vcpu_aia_rmw_topei },
> >
> > -static inline int kvm_riscv_vcpu_aia_update(struct kvm_vcpu *vcpu)
> > -{
> > - return 1;
> > -}
> > -
> > -static inline void kvm_riscv_vcpu_aia_reset(struct kvm_vcpu *vcpu)
> > -{
> > -}
> > -
> > -static inline int kvm_riscv_vcpu_aia_init(struct kvm_vcpu *vcpu)
> > -{
> > - return 0;
> > -}
> > -
> > -static inline void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu)
> > -{
> > -}
> > -
> > -static inline int kvm_riscv_aia_inject_msi_by_id(struct kvm *kvm,
> > - u32 hart_index,
> > - u32 guest_index, u32 iid)
> > -{
> > - return 0;
> > -}
> > -
> > -static inline int kvm_riscv_aia_inject_msi(struct kvm *kvm,
> > - struct kvm_msi *msi)
> > -{
> > - return 0;
> > -}
> > +int kvm_riscv_vcpu_aia_update(struct kvm_vcpu *vcpu);
> > +void kvm_riscv_vcpu_aia_reset(struct kvm_vcpu *vcpu);
> > +int kvm_riscv_vcpu_aia_init(struct kvm_vcpu *vcpu);
> > +void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu);
> >
> > -static inline int kvm_riscv_aia_inject_irq(struct kvm *kvm,
> > - unsigned int irq, bool level)
> > -{
> > - return 0;
> > -}
> > +int kvm_riscv_aia_inject_msi_by_id(struct kvm *kvm, u32 hart_index,
> > + u32 guest_index, u32 iid);
> > +int kvm_riscv_aia_inject_msi(struct kvm *kvm, struct kvm_msi *msi);
> > +int kvm_riscv_aia_inject_irq(struct kvm *kvm, unsigned int irq, bool level);
> >
> > -static inline void kvm_riscv_aia_init_vm(struct kvm *kvm)
> > -{
> > -}
> > -
> > -static inline void kvm_riscv_aia_destroy_vm(struct kvm *kvm)
> > -{
> > -}
> > +void kvm_riscv_aia_init_vm(struct kvm *kvm);
> > +void kvm_riscv_aia_destroy_vm(struct kvm *kvm);
> >
> > int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner,
> > void __iomem **hgei_va, phys_addr_t *hgei_pa);
> > diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> > index 332d4a274891..047c8fc5bd71 100644
> > --- a/arch/riscv/include/uapi/asm/kvm.h
> > +++ b/arch/riscv/include/uapi/asm/kvm.h
> > @@ -204,6 +204,51 @@ enum KVM_RISCV_SBI_EXT_ID {
> > #define KVM_REG_RISCV_SBI_MULTI_REG_LAST \
> > KVM_REG_RISCV_SBI_MULTI_REG(KVM_RISCV_SBI_EXT_MAX - 1)
> >
> > +/* Device Control API: RISC-V AIA */
> > +#define KVM_DEV_RISCV_APLIC_ALIGN 0x1000
> > +#define KVM_DEV_RISCV_APLIC_SIZE 0x4000
> > +#define KVM_DEV_RISCV_APLIC_MAX_HARTS 0x4000
> > +#define KVM_DEV_RISCV_IMSIC_ALIGN 0x1000
> > +#define KVM_DEV_RISCV_IMSIC_SIZE 0x1000
> > +
> > +#define KVM_DEV_RISCV_AIA_GRP_CONFIG 0
> > +#define KVM_DEV_RISCV_AIA_CONFIG_MODE 0
> > +#define KVM_DEV_RISCV_AIA_CONFIG_IDS 1
> > +#define KVM_DEV_RISCV_AIA_CONFIG_SRCS 2
> > +#define KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS 3
> > +#define KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT 4
> > +#define KVM_DEV_RISCV_AIA_CONFIG_HART_BITS 5
> > +#define KVM_DEV_RISCV_AIA_CONFIG_GUEST_BITS 6
> > +
> > +/*
> > + * Modes of RISC-V AIA device:
> > + * 1) EMUL (aka Emulation): Trap-n-emulate IMSIC
> > + * 2) HWACCEL (aka HW Acceleration): Virtualize IMSIC using IMSIC guest files
> > + * 3) AUTO (aka Automatic): Virtualize IMSIC using IMSIC guest files whenever
> > + * available otherwise fallback to trap-n-emulation
> > + */
> > +#define KVM_DEV_RISCV_AIA_MODE_EMUL 0
> > +#define KVM_DEV_RISCV_AIA_MODE_HWACCEL 1
> > +#define KVM_DEV_RISCV_AIA_MODE_AUTO 2
> > +
> > +#define KVM_DEV_RISCV_AIA_IDS_MIN 63
> > +#define KVM_DEV_RISCV_AIA_IDS_MAX 2048
> > +#define KVM_DEV_RISCV_AIA_SRCS_MAX 1024
> > +#define KVM_DEV_RISCV_AIA_GROUP_BITS_MAX 8
> > +#define KVM_DEV_RISCV_AIA_GROUP_SHIFT_MIN 24
> > +#define KVM_DEV_RISCV_AIA_GROUP_SHIFT_MAX 56
> > +#define KVM_DEV_RISCV_AIA_HART_BITS_MAX 16
> > +#define KVM_DEV_RISCV_AIA_GUEST_BITS_MAX 8
> > +
> > +#define KVM_DEV_RISCV_AIA_GRP_ADDR 1
> > +#define KVM_DEV_RISCV_AIA_ADDR_APLIC 0
> > +#define KVM_DEV_RISCV_AIA_ADDR_IMSIC(__vcpu) (1 + (__vcpu))
> > +#define KVM_DEV_RISCV_AIA_ADDR_MAX \
> > + (1 + KVM_DEV_RISCV_APLIC_MAX_HARTS)
> > +
> > +#define KVM_DEV_RISCV_AIA_GRP_CTRL 2
> > +#define KVM_DEV_RISCV_AIA_CTRL_INIT 0
> > +
> > /* One single KVM irqchip, ie. the AIA */
> > #define KVM_NR_IRQCHIPS 1
> >
> > diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> > index 8031b8912a0d..dd69ebe098bd 100644
> > --- a/arch/riscv/kvm/Makefile
> > +++ b/arch/riscv/kvm/Makefile
> > @@ -27,3 +27,4 @@ kvm-y += vcpu_sbi_hsm.o
> > kvm-y += vcpu_timer.o
> > kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
> > kvm-y += aia.o
> > +kvm-y += aia_device.o
> > diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
> > index 18c442c15ff2..585a3b42c52c 100644
> > --- a/arch/riscv/kvm/aia.c
> > +++ b/arch/riscv/kvm/aia.c
> > @@ -631,6 +631,14 @@ int kvm_riscv_aia_init(void)
> > if (rc)
> > return rc;
> >
> > + /* Register device operations */
> > + rc = kvm_register_device_ops(&kvm_riscv_aia_device_ops,
> > + KVM_DEV_TYPE_RISCV_AIA);
> > + if (rc) {
> > + aia_hgei_exit();
> > + return rc;
> > + }
> > +
> > /* Enable KVM AIA support */
> > static_branch_enable(&kvm_riscv_aia_available);
> >
> > @@ -642,6 +650,9 @@ void kvm_riscv_aia_exit(void)
> > if (!kvm_riscv_aia_available())
> > return;
> >
> > + /* Unregister device operations */
> > + kvm_unregister_device_ops(KVM_DEV_TYPE_RISCV_AIA);
> > +
> > /* Cleanup the HGEI state */
> > aia_hgei_exit();
> > }
> > diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> > new file mode 100644
> > index 000000000000..a151fb357887
> > --- /dev/null
> > +++ b/arch/riscv/kvm/aia_device.c
> > @@ -0,0 +1,622 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + * Copyright (C) 2022 Ventana Micro Systems Inc.
> > + *
> > + * Authors:
> > + * Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > + */
> > +
> > +#include <linux/bits.h>
> > +#include <linux/kvm_host.h>
> > +#include <linux/uaccess.h>
> > +#include <asm/kvm_aia_imsic.h>
> > +
> > +static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
> > +{
> > + struct kvm_vcpu *tmp_vcpu;
> > +
> > + for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
> > + tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
> > + mutex_unlock(&tmp_vcpu->mutex);
> > + }
> > +}
> > +
> > +static void unlock_all_vcpus(struct kvm *kvm)
> > +{
> > + unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
> > +}
> > +
> > +static bool lock_all_vcpus(struct kvm *kvm)
> > +{
> > + struct kvm_vcpu *tmp_vcpu;
> > + unsigned long c;
> > +
> > + kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
> > + if (!mutex_trylock(&tmp_vcpu->mutex)) {
> > + unlock_vcpus(kvm, c - 1);
> > + return false;
> > + }
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static int aia_create(struct kvm_device *dev, u32 type)
> > +{
> > + int ret;
> > + unsigned long i;
> > + struct kvm *kvm = dev->kvm;
> > + struct kvm_vcpu *vcpu;
> > +
> > + if (irqchip_in_kernel(kvm))
> > + return -EEXIST;
> > +
> > + ret = -EBUSY;
> > + if (!lock_all_vcpus(kvm))
> > + return ret;
> > +
> > + kvm_for_each_vcpu(i, vcpu, kvm) {
> > + if (vcpu->arch.ran_atleast_once)
> > + goto out_unlock;
> > + }
> > + ret = 0;
> > +
> > + kvm->arch.aia.in_kernel = true;
> > +
> > +out_unlock:
> > + unlock_all_vcpus(kvm);
> > + return ret;
> > +}
> > +
> > +static void aia_destroy(struct kvm_device *dev)
> > +{
> > + kfree(dev);
> > +}
> > +
> > +static int aia_config(struct kvm *kvm, unsigned long type,
> > + u32 *nr, bool write)
> > +{
> > + struct kvm_aia *aia = &kvm->arch.aia;
> > +
> > + /* Writes can only be done before irqchip is initialized */
> > + if (write && kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + switch (type) {
> > + case KVM_DEV_RISCV_AIA_CONFIG_MODE:
> > + if (write) {
> > + switch (*nr) {
> > + case KVM_DEV_RISCV_AIA_MODE_EMUL:
> > + break;
> > + case KVM_DEV_RISCV_AIA_MODE_HWACCEL:
> > + case KVM_DEV_RISCV_AIA_MODE_AUTO:
> > + /*
> > + * HW Acceleration and Auto modes only
> > + * supported on host with non-zero guest
> > + * external interrupts (i.e. non-zero
> > + * VS-level IMSIC pages).
> > + */
> > + if (!kvm_riscv_aia_nr_hgei)
> > + return -EINVAL;
> > + break;
> > + default:
> > + return -EINVAL;
> > + };
> > + aia->mode = *nr;
> > + } else
> > + *nr = aia->mode;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_IDS:
> > + if (write) {
> > + if ((*nr < KVM_DEV_RISCV_AIA_IDS_MIN) ||
> > + (*nr >= KVM_DEV_RISCV_AIA_IDS_MAX) ||
> > + (*nr & KVM_DEV_RISCV_AIA_IDS_MIN) ||
>
> The msi number is one less than a multiple of 64. This line should be
> ((*nr & KVM_DEV_RISCV_AIA_IDS_MIN) != KVM_DEV_RISCV_AIA_IDS_MIN)

Good catch. I will fix it in the next revision.

>
> > + (kvm_riscv_aia_max_ids <= *nr))
> > + return -EINVAL;
> > + aia->nr_ids = *nr;
> > + } else
> > + *nr = aia->nr_ids;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_SRCS:
> > + if (write) {
> > + if ((*nr >= KVM_DEV_RISCV_AIA_SRCS_MAX) ||
> > + (*nr >= kvm_riscv_aia_max_ids))
> > + return -EINVAL;
> > + aia->nr_sources = *nr;
> > + } else
> > + *nr = aia->nr_sources;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS:
> > + if (write) {
> > + if (*nr >= KVM_DEV_RISCV_AIA_GROUP_BITS_MAX)
> > + return -EINVAL;
> > + aia->nr_group_bits = *nr;
> > + } else
> > + *nr = aia->nr_group_bits;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT:
> > + if (write) {
> > + if ((*nr < KVM_DEV_RISCV_AIA_GROUP_SHIFT_MIN) ||
> > + (*nr >= KVM_DEV_RISCV_AIA_GROUP_SHIFT_MAX))
> > + return -EINVAL;
> > + aia->nr_group_shift = *nr;
> > + } else
> > + *nr = aia->nr_group_shift;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_HART_BITS:
> > + if (write) {
> > + if (*nr >= KVM_DEV_RISCV_AIA_HART_BITS_MAX)
> > + return -EINVAL;
> > + aia->nr_hart_bits = *nr;
> > + } else
> > + *nr = aia->nr_hart_bits;
> > + break;
> > + case KVM_DEV_RISCV_AIA_CONFIG_GUEST_BITS:
> > + if (write) {
> > + if (*nr >= KVM_DEV_RISCV_AIA_GUEST_BITS_MAX)
> > + return -EINVAL;
> > + aia->nr_guest_bits = *nr;
> > + } else
> > + *nr = aia->nr_guest_bits;
> > + break;
> > + default:
> > + return -ENXIO;
> > + };
> > +
> > + return 0;
> > +}
> > +
> > +static int aia_aplic_addr(struct kvm *kvm, u64 *addr, bool write)
> > +{
> > + struct kvm_aia *aia = &kvm->arch.aia;
> > +
> > + if (write) {
> > + /* Writes can only be done before irqchip is initialized */
> > + if (kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + if (*addr & (KVM_DEV_RISCV_APLIC_ALIGN - 1))
> > + return -EINVAL;
> > +
> > + aia->aplic_addr = *addr;
> > + } else
> > + *addr = aia->aplic_addr;
> > +
> > + return 0;
> > +}
> > +
> > +static int aia_imsic_addr(struct kvm *kvm, u64 *addr,
> > + unsigned long vcpu_idx, bool write)
> > +{
> > + struct kvm_vcpu *vcpu;
> > + struct kvm_vcpu_aia *vcpu_aia;
> > +
> > + vcpu = kvm_get_vcpu(kvm, vcpu_idx);
> > + if (!vcpu)
> > + return -EINVAL;
> > + vcpu_aia = &vcpu->arch.aia_context;
> > +
> > + if (write) {
> > + /* Writes can only be done before irqchip is initialized */
> > + if (kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + if (*addr & (KVM_DEV_RISCV_IMSIC_ALIGN - 1))
> > + return -EINVAL;
> > + }
> > +
> > + mutex_lock(&vcpu->mutex);
> > + if (write)
> > + vcpu_aia->imsic_addr = *addr;
> > + else
> > + *addr = vcpu_aia->imsic_addr;
> > + mutex_unlock(&vcpu->mutex);
> > +
> > + return 0;
> > +}
> > +
> > +static gpa_t aia_imsic_ppn(struct kvm_aia *aia, gpa_t addr)
> > +{
> > + u32 h, l;
> > + gpa_t mask = 0;
> > +
> > + h = aia->nr_hart_bits + aia->nr_guest_bits +
> > + IMSIC_MMIO_PAGE_SHIFT - 1;
> > + mask = GENMASK_ULL(h, 0);
> > +
> > + if (aia->nr_group_bits) {
> > + h = aia->nr_group_bits + aia->nr_group_shift - 1;
> > + l = aia->nr_group_shift;
> > + mask |= GENMASK_ULL(h, l);
> > + }
> > +
> > + return (addr & ~mask) >> IMSIC_MMIO_PAGE_SHIFT;
> > +}
> > +
> > +static u32 aia_imsic_hart_index(struct kvm_aia *aia, gpa_t addr)
> > +{
> > + u32 hart, group = 0;
> > +
> > + hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> > + GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> > + if (aia->nr_group_bits)
> > + group = (addr >> aia->nr_group_shift) &
> > + GENMASK_ULL(aia->nr_group_bits - 1, 0);
> > +
> > + return (group << aia->nr_hart_bits) | hart;
> > +}
> > +
> > +static int aia_init(struct kvm *kvm)
> > +{
> > + int ret, i;
> > + unsigned long idx;
> > + struct kvm_vcpu *vcpu;
> > + struct kvm_vcpu_aia *vaia;
> > + struct kvm_aia *aia = &kvm->arch.aia;
> > + gpa_t base_ppn = KVM_RISCV_AIA_UNDEF_ADDR;
> > +
> > + /* Irqchip can be initialized only once */
> > + if (kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + /* We might be in the middle of creating a VCPU? */
> > + if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
> > + return -EBUSY;
> > +
> > + /* Number of sources should be less than or equals number of IDs */
> > + if (aia->nr_ids < aia->nr_sources)
> > + return -EINVAL;
> > +
> > + /* APLIC base is required for non-zero number of sources */
> > + if (aia->nr_sources && aia->aplic_addr == KVM_RISCV_AIA_UNDEF_ADDR)
> > + return -EINVAL;
> > +
> > + /* Initialize APLIC */
> > + ret = kvm_riscv_aia_aplic_init(kvm);
> > + if (ret)
> > + return ret;
> > +
> > + /* Iterate over each VCPU */
> > + kvm_for_each_vcpu(idx, vcpu, kvm) {
> > + vaia = &vcpu->arch.aia_context;
> > +
> > + /* IMSIC base is required */
> > + if (vaia->imsic_addr == KVM_RISCV_AIA_UNDEF_ADDR) {
> > + ret = -EINVAL;
> > + goto fail_cleanup_imsics;
> > + }
> > +
> > + /* All IMSICs should have matching base PPN */
> > + if (base_ppn == KVM_RISCV_AIA_UNDEF_ADDR)
> > + base_ppn = aia_imsic_ppn(aia, vaia->imsic_addr);
> > + if (base_ppn != aia_imsic_ppn(aia, vaia->imsic_addr)) {
> > + ret = -EINVAL;
> > + goto fail_cleanup_imsics;
> > + }
> > +
> > + /* Update HART index of the IMSIC based on IMSIC base */
> > + vaia->hart_index = aia_imsic_hart_index(aia,
> > + vaia->imsic_addr);
> > +
> > + /* Initialize IMSIC for this VCPU */
> > + ret = kvm_riscv_vcpu_aia_imsic_init(vcpu);
> > + if (ret)
> > + goto fail_cleanup_imsics;
> > + }
> > +
> > + /* Set the initialized flag */
> > + kvm->arch.aia.initialized = true;
> > +
> > + return 0;
> > +
> > +fail_cleanup_imsics:
> > + for (i = idx - 1; i >= 0; i--) {
> > + vcpu = kvm_get_vcpu(kvm, i);
> > + if (!vcpu)
> > + continue;
> > + kvm_riscv_vcpu_aia_imsic_cleanup(vcpu);
> > + }
> > + kvm_riscv_aia_aplic_cleanup(kvm);
> > + return ret;
> > +}
> > +
> > +static int aia_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
> > +{
> > + u32 nr;
> > + u64 addr;
> > + int nr_vcpus, r = -ENXIO;
> > + unsigned long type = (unsigned long)attr->attr;
> > + void __user *uaddr = (void __user *)(long)attr->addr;
> > +
> > + switch (attr->group) {
> > + case KVM_DEV_RISCV_AIA_GRP_CONFIG:
> > + if (copy_from_user(&nr, uaddr, sizeof(nr)))
> > + return -EFAULT;
> > +
> > + mutex_lock(&dev->kvm->lock);
> > + r = aia_config(dev->kvm, type, &nr, true);
> > + mutex_unlock(&dev->kvm->lock);
> > +
> > + break;
> > +
> > + case KVM_DEV_RISCV_AIA_GRP_ADDR:
> > + if (copy_from_user(&addr, uaddr, sizeof(addr)))
> > + return -EFAULT;
> > +
> > + nr_vcpus = atomic_read(&dev->kvm->online_vcpus);
> > + mutex_lock(&dev->kvm->lock);
> > + if (type == KVM_DEV_RISCV_AIA_ADDR_APLIC)
> > + r = aia_aplic_addr(dev->kvm, &addr, true);
> > + else if (type < KVM_DEV_RISCV_AIA_ADDR_IMSIC(nr_vcpus))
> > + r = aia_imsic_addr(dev->kvm, &addr,
> > + type - KVM_DEV_RISCV_AIA_ADDR_IMSIC(0), true);
> > + mutex_unlock(&dev->kvm->lock);
> > +
> > + break;
> > +
> > + case KVM_DEV_RISCV_AIA_GRP_CTRL:
> > + switch (type) {
> > + case KVM_DEV_RISCV_AIA_CTRL_INIT:
> > + mutex_lock(&dev->kvm->lock);
> > + r = aia_init(dev->kvm);
> > + mutex_unlock(&dev->kvm->lock);
> > + break;
> > + }
> > +
> > + break;
> > + }
> > +
> > + return r;
> > +}
> > +
> > +static int aia_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
> > +{
> > + u32 nr;
> > + u64 addr;
> > + int nr_vcpus, r = -ENXIO;
> > + void __user *uaddr = (void __user *)(long)attr->addr;
> > + unsigned long type = (unsigned long)attr->attr;
> > +
> > + switch (attr->group) {
> > + case KVM_DEV_RISCV_AIA_GRP_CONFIG:
> > + if (copy_from_user(&nr, uaddr, sizeof(nr)))
> > + return -EFAULT;
> > +
> > + mutex_lock(&dev->kvm->lock);
> > + r = aia_config(dev->kvm, type, &nr, false);
> > + mutex_unlock(&dev->kvm->lock);
> > + if (r)
> > + return r;
> > +
> > + if (copy_to_user(uaddr, &nr, sizeof(nr)))
> > + return -EFAULT;
> > +
> > + break;
> > + case KVM_DEV_RISCV_AIA_GRP_ADDR:
> > + if (copy_from_user(&addr, uaddr, sizeof(addr)))
> > + return -EFAULT;
> > +
> > + nr_vcpus = atomic_read(&dev->kvm->online_vcpus);
> > + mutex_lock(&dev->kvm->lock);
> > + if (type == KVM_DEV_RISCV_AIA_ADDR_APLIC)
> > + r = aia_aplic_addr(dev->kvm, &addr, false);
> > + else if (type < KVM_DEV_RISCV_AIA_ADDR_IMSIC(nr_vcpus))
> > + r = aia_imsic_addr(dev->kvm, &addr,
> > + type - KVM_DEV_RISCV_AIA_ADDR_IMSIC(0), false);
> > + mutex_unlock(&dev->kvm->lock);
> > + if (r)
> > + return r;
> > +
> > + if (copy_to_user(uaddr, &addr, sizeof(addr)))
> > + return -EFAULT;
> > +
> > + break;
> > + }
> > +
> > + return r;
> > +}
> > +
> > +static int aia_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
> > +{
> > + int nr_vcpus;
> > +
> > + switch (attr->group) {
> > + case KVM_DEV_RISCV_AIA_GRP_CONFIG:
> > + switch (attr->attr) {
> > + case KVM_DEV_RISCV_AIA_CONFIG_MODE:
> > + case KVM_DEV_RISCV_AIA_CONFIG_IDS:
> > + case KVM_DEV_RISCV_AIA_CONFIG_SRCS:
> > + case KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS:
> > + case KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT:
> > + case KVM_DEV_RISCV_AIA_CONFIG_HART_BITS:
> > + case KVM_DEV_RISCV_AIA_CONFIG_GUEST_BITS:
> > + return 0;
> > + }
> > + break;
> > + case KVM_DEV_RISCV_AIA_GRP_ADDR:
> > + nr_vcpus = atomic_read(&dev->kvm->online_vcpus);
> > + if (attr->attr == KVM_DEV_RISCV_AIA_ADDR_APLIC)
> > + return 0;
> > + else if (attr->attr < KVM_DEV_RISCV_AIA_ADDR_IMSIC(nr_vcpus))
> > + return 0;
> > + break;
> > + case KVM_DEV_RISCV_AIA_GRP_CTRL:
> > + switch (attr->attr) {
> > + case KVM_DEV_RISCV_AIA_CTRL_INIT:
> > + return 0;
> > + }
> > + break;
> > + }
> > +
> > + return -ENXIO;
> > +}
> > +
> > +struct kvm_device_ops kvm_riscv_aia_device_ops = {
> > + .name = "kvm-riscv-aia",
> > + .create = aia_create,
> > + .destroy = aia_destroy,
> > + .set_attr = aia_set_attr,
> > + .get_attr = aia_get_attr,
> > + .has_attr = aia_has_attr,
> > +};
> > +
> > +int kvm_riscv_vcpu_aia_update(struct kvm_vcpu *vcpu)
> > +{
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(vcpu->kvm))
> > + return 1;
> > +
> > + /* Update the IMSIC HW state before entering guest mode */
> > + return kvm_riscv_vcpu_aia_imsic_update(vcpu);
> > +}
> > +
> > +void kvm_riscv_vcpu_aia_reset(struct kvm_vcpu *vcpu)
> > +{
> > + struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;
> > + struct kvm_vcpu_aia_csr *reset_csr =
> > + &vcpu->arch.aia_context.guest_reset_csr;
> > +
> > + if (!kvm_riscv_aia_available())
> > + return;
> > + memcpy(csr, reset_csr, sizeof(*csr));
> > +
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(vcpu->kvm))
> > + return;
> > +
> > + /* Reset the IMSIC context */
> > + kvm_riscv_vcpu_aia_imsic_reset(vcpu);
> > +}
> > +
> > +int kvm_riscv_vcpu_aia_init(struct kvm_vcpu *vcpu)
> > +{
> > + struct kvm_vcpu_aia *vaia = &vcpu->arch.aia_context;
> > +
> > + if (!kvm_riscv_aia_available())
> > + return 0;
> > +
> > + /*
> > + * We don't do any memory allocations over here because these
> > + * will be done after AIA device is initialized by the user-space.
> > + *
> > + * Refer, aia_init() implementation for more details.
> > + */
> > +
> > + /* Initialize default values in AIA vcpu context */
> > + vaia->imsic_addr = KVM_RISCV_AIA_UNDEF_ADDR;
> > + vaia->hart_index = vcpu->vcpu_idx;
> > +
> > + return 0;
> > +}
> > +
> > +void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu)
> > +{
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(vcpu->kvm))
> > + return;
> > +
> > + /* Cleanup IMSIC context */
> > + kvm_riscv_vcpu_aia_imsic_cleanup(vcpu);
> > +}
> > +
> > +int kvm_riscv_aia_inject_msi_by_id(struct kvm *kvm, u32 hart_index,
> > + u32 guest_index, u32 iid)
> > +{
> > + unsigned long idx;
> > + struct kvm_vcpu *vcpu;
> > +
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + /* Inject MSI to matching VCPU */
> > + kvm_for_each_vcpu(idx, vcpu, kvm) {
> > + if (vcpu->arch.aia_context.hart_index == hart_index)
> > + return kvm_riscv_vcpu_aia_imsic_inject(vcpu,
> > + guest_index,
> > + 0, iid);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int kvm_riscv_aia_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
> > +{
> > + gpa_t tppn, ippn;
> > + unsigned long idx;
> > + struct kvm_vcpu *vcpu;
> > + u32 g, toff, iid = msi->data;
> > + struct kvm_aia *aia = &kvm->arch.aia;
> > + gpa_t target = (((gpa_t)msi->address_hi) << 32) | msi->address_lo;
> > +
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + /* Convert target address to target PPN */
> > + tppn = target >> IMSIC_MMIO_PAGE_SHIFT;
> > +
> > + /* Extract and clear Guest ID from target PPN */
> > + g = tppn & (BIT(aia->nr_guest_bits) - 1);
> > + tppn &= ~((gpa_t)(BIT(aia->nr_guest_bits) - 1));
> > +
> > + /* Inject MSI to matching VCPU */
> > + kvm_for_each_vcpu(idx, vcpu, kvm) {
> > + ippn = vcpu->arch.aia_context.imsic_addr >>
> > + IMSIC_MMIO_PAGE_SHIFT;
> > + if (ippn == tppn) {
> > + toff = target & (IMSIC_MMIO_PAGE_SZ - 1);
> > + return kvm_riscv_vcpu_aia_imsic_inject(vcpu, g,
> > + toff, iid);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int kvm_riscv_aia_inject_irq(struct kvm *kvm, unsigned int irq, bool level)
> > +{
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(kvm))
> > + return -EBUSY;
> > +
> > + /* Inject interrupt level change in APLIC */
> > + return kvm_riscv_aia_aplic_inject(kvm, irq, level);
> > +}
> > +
> > +void kvm_riscv_aia_init_vm(struct kvm *kvm)
> > +{
> > + struct kvm_aia *aia = &kvm->arch.aia;
> > +
> > + if (!kvm_riscv_aia_available())
> > + return;
> > +
> > + /*
> > + * We don't do any memory allocations over here because these
> > + * will be done after AIA device is initialized by the user-space.
> > + *
> > + * Refer, aia_init() implementation for more details.
> > + */
> > +
> > + /* Initialize default values in AIA global context */
> > + aia->mode = (kvm_riscv_aia_nr_hgei) ?
> > + KVM_DEV_RISCV_AIA_MODE_AUTO : KVM_DEV_RISCV_AIA_MODE_EMUL;
> > + aia->nr_ids = kvm_riscv_aia_max_ids - 1;
> > + aia->nr_sources = 0;
> > + aia->nr_group_bits = 0;
> > + aia->nr_group_shift = KVM_DEV_RISCV_AIA_GROUP_SHIFT_MIN;
> > + aia->nr_hart_bits = 0;
> > + aia->nr_guest_bits = 0;
> > + aia->aplic_addr = KVM_RISCV_AIA_UNDEF_ADDR;
> > +}
> > +
> > +void kvm_riscv_aia_destroy_vm(struct kvm *kvm)
> > +{
> > + /* Proceed only if AIA was initialized successfully */
> > + if (!kvm_riscv_aia_initialized(kvm))
> > + return;
> > +
> > + /* Cleanup APLIC context */
> > + kvm_riscv_aia_aplic_cleanup(kvm);
> > +}
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index 737318b1c1d9..27ccd07898e1 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -1442,6 +1442,8 @@ enum kvm_device_type {
> > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE
> > KVM_DEV_TYPE_ARM_PV_TIME,
> > #define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME
> > + KVM_DEV_TYPE_RISCV_AIA,
> > +#define KVM_DEV_TYPE_RISCV_AIA KVM_DEV_TYPE_RISCV_AIA
> > KVM_DEV_TYPE_MAX,
> > };
> >
> > --
> > 2.34.1
> >
>
> Additionally, it might be necessary to consider adding KVM_CAP_IRQCHIP
> in the kvm_vm_ioctl_check_extension() function when the KVM AIA chip
> is present.
>

Advertising KVM_CAP_IRQCHIP is not of much use since KVM user space
can already discover the presence of AIA device. I will add it anyway.

Regards,
Anup

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