Re: [RFC PATCH v3 6/6] kvm/ppc/mpic: add KVM_CAP_IRQ_MPIC

Alexander Graf
2013-04-04T12:54:20Z

On 03.04.2013, at 03:57, Scott Wood wrote:

> Enabling this capability connects the vcpu to the designated in-kernel
> MPIC. Using explicit connections between vcpus and irqchips allows
> for flexibility, but the main benefit at the moment is that it
> simplifies the code -- KVM doesn't need vm-global state to remember
> which MPIC object is associated with this vm, and it doesn't need to
> care about ordering between irqchip creation and vcpu creation.
>
> Signed-off-by: Scott Wood <scottwood@freescale.com>
> ---
> Documentation/virtual/kvm/api.txt | 8 ++++++
> arch/powerpc/include/asm/kvm_host.h | 8 ++++++
> arch/powerpc/include/asm/kvm_ppc.h | 2 ++
> arch/powerpc/kvm/booke.c | 4 ++-
> arch/powerpc/kvm/mpic.c | 49 +++++++++++++++++++++++++++++++----
> arch/powerpc/kvm/powerpc.c | 26 +++++++++++++++++++
> include/uapi/linux/kvm.h | 1 +
> 7 files changed, 92 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index d52f3f9..4c326ae 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -2728,3 +2728,11 @@ to receive the topmost interrupt vector.
> When disabled (args[0] = 0), behavior is as if this facility is unsupported.
>
> When this capability is enabled, KVM_EXIT_EPR can occur.
> +
> +6.6 KVM_CAP_IRQ_MPIC
> +
> +Architectures: ppc
> +Parameters: args[0] is the MPIC device fd
> + args[1] is the MPIC CPU number for this vcpu
> +
> +This capability connects the vcpu to an in-kernel MPIC device.
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 7e7aef9..2a2e235 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -375,6 +375,11 @@ struct kvmppc_booke_debug_reg {
> u64 dac[KVMPPC_BOOKE_MAX_DAC];
> };
>
> +#define KVMPPC_IRQ_DEFAULT 0
> +#define KVMPPC_IRQ_MPIC 1
> +
> +struct openpic;
> +
> struct kvm_vcpu_arch {
> ulong host_stack;
> u32 host_pid;
> @@ -554,6 +559,9 @@ struct kvm_vcpu_arch {
> unsigned long magic_page_pa; /* phys addr to map the magic page to */
> unsigned long magic_page_ea; /* effect. addr to map the magic page to */
>
> + int irq_type; /* one of KVM_IRQ_* */
> + struct openpic *mpic; /* KVM_IRQ_MPIC */
> +
> #ifdef CONFIG_KVM_BOOK3S_64_HV
> struct kvm_vcpu_arch_shared shregs;
>
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index 3b63b97..f54707f 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -276,6 +276,8 @@ static inline void kvmppc_set_epr(struct kvm_vcpu *vcpu, u32 epr)
> }
>
> void kvmppc_mpic_set_epr(struct kvm_vcpu *vcpu);
> +int kvmppc_mpic_connect_vcpu(struct file *mpic_filp, struct kvm_vcpu *vcpu,
> + u32 cpu);
>
> int kvm_vcpu_ioctl_config_tlb(struct kvm_vcpu *vcpu,
> struct kvm_config_tlb *cfg);
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index cddc6b3..7d00222 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -430,8 +430,10 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
> if (update_epr = true) {
> if (vcpu->arch.epr_flags & KVMPPC_EPR_USER)
> kvm_make_request(KVM_REQ_EPR_EXIT, vcpu);
> - else if (vcpu->arch.epr_flags & KVMPPC_EPR_KERNEL)
> + else if (vcpu->arch.epr_flags & KVMPPC_EPR_KERNEL) {
> + BUG_ON(vcpu->arch.irq_type != KVMPPC_IRQ_MPIC);
> kvmppc_mpic_set_epr(vcpu);
> + }
> }
>
> new_msr &= msr_mask;
> diff --git a/arch/powerpc/kvm/mpic.c b/arch/powerpc/kvm/mpic.c
> index 8cda2fa..caffe3b 100644
> --- a/arch/powerpc/kvm/mpic.c
> +++ b/arch/powerpc/kvm/mpic.c
> @@ -1159,7 +1159,7 @@ static uint32_t openpic_iack(struct openpic *opp, struct irq_dest *dst,
>
> void kvmppc_mpic_set_epr(struct kvm_vcpu *vcpu)
> {
> - struct openpic *opp = vcpu->arch.irqchip_priv;
> + struct openpic *opp = vcpu->arch.mpic;
> int cpu = vcpu->vcpu_id;
> unsigned long flags;
>
> @@ -1442,10 +1442,10 @@ static void map_mmio(struct openpic *opp)
>
> static void unmap_mmio(struct openpic *opp)
> {
> - BUG_ON(opp->mmio_mapped);
> - opp->mmio_mapped = false;
> -
> - kvm_io_bus_unregister_dev(opp->kvm, KVM_MMIO_BUS, &opp->mmio);
> + if (opp->mmio_mapped) {
> + opp->mmio_mapped = false;
> + kvm_io_bus_unregister_dev(opp->kvm, KVM_MMIO_BUS, &opp->mmio);
> + }
> }
>
> static int set_base_addr(struct openpic *opp, struct kvm_device_attr *attr)
> @@ -1681,6 +1681,45 @@ static const struct file_operations kvm_mpic_fops = {
> .release = kvm_mpic_release,
> };
>
> +int kvmppc_mpic_connect_vcpu(struct file *mpic_filp, struct kvm_vcpu *vcpu,
> + u32 cpu)
> +{
> + struct openpic *opp = mpic_filp->private_data;
> + int ret = 0;
> +
> + if (mpic_filp->f_op != &kvm_mpic_fops)
> + return -EPERM;
> + if (opp->kvm != vcpu->kvm)
> + return -EPERM;
> + if (cpu < 0 || cpu >= MAX_CPU)
> + return -EPERM;
> +
> + spin_lock_irq(&opp->lock);
> +
> + if (opp->dst[cpu].vcpu) {
> + ret = -EEXIST;
> + goto out;
> + }
> + if (vcpu->arch.irq_type) {
> + return -EBUSY;
> + goto out;
> + }
> +
> + opp->dst[cpu].vcpu = vcpu;
> + opp->nb_cpus = max(opp->nb_cpus, cpu + 1);
> +
> + vcpu->arch.mpic = opp;
> + vcpu->arch.irq_type = KVMPPC_IRQ_MPIC;
> + atomic_inc(&opp->users);
> +
> + if (opp->mpic_mode_mask = GCR_MODE_PROXY)

Shouldn't this be an &?

> + vcpu->arch.epr_flags |= KVMPPC_EPR_KERNEL;
> +
> +out:
> + spin_unlock_irq(&opp->lock);
> + return ret;
> +}
> +
> int kvm_create_mpic(struct kvm *kvm, u32 type)
> {
> struct openpic *opp;
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index c9a2972..290a905 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -25,6 +25,7 @@
> #include <linux/hrtimer.h>
> #include <linux/fs.h>
> #include <linux/slab.h>
> +#include <linux/file.h>
> #include <asm/cputable.h>
> #include <asm/uaccess.h>
> #include <asm/kvm_ppc.h>
> @@ -327,6 +328,9 @@ int kvm_dev_ioctl_check_extension(long ext)
> #if defined(CONFIG_KVM_E500V2) || defined(CONFIG_KVM_E500MC)
> case KVM_CAP_SW_TLB:
> #endif
> +#ifdef CONFIG_KVM_MPIC
> + case KVM_CAP_IRQ_MPIC:
> +#endif
> r = 1;
> break;
> case KVM_CAP_COALESCED_MMIO:
> @@ -460,6 +464,13 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
> tasklet_kill(&vcpu->arch.tasklet);
>
> kvmppc_remove_vcpu_debugfs(vcpu);
> +
> + switch (vcpu->arch.irq_type) {
> + case KVMPPC_IRQ_MPIC:
> + kvmppc_mpic_put(vcpu->arch.mpic);

This doesn't tell the MPIC that this exact CPU is getting killed. What if we hotplug remove just a single CPU? Don't we have to deregister the CPU with the MPIC?

Alex