* Re: [Android-virt] [PATCH 10/15] ARM: KVM: VGIC: Update KVM API documentation
[not found] ` <1337000795-15825-1-git-send-email-marc.zyngier@arm.com>
@ 2012-06-22 21:08 ` Christoffer Dall
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From: Christoffer Dall @ 2012-06-22 21:08 UTC (permalink / raw
To: Marc Zyngier; +Cc: android-virt, kvm
I've cc'ed the KVM list to get their early input on this.
On Mon, May 14, 2012 at 9:06 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> Reflect the changes in the API due to the introduction of VGIC.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> Documentation/virtual/kvm/api.txt | 24 +++++++++++++++++-------
> 1 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 8a3628f..5f6b683 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -600,7 +600,7 @@ struct kvm_fpu {
> 4.24 KVM_CREATE_IRQCHIP
>
> Capability: KVM_CAP_IRQCHIP
> -Architectures: x86, ia64
> +Architectures: x86, ia64, ARM
> Type: vm ioctl
> Parameters: none
> Returns: 0 on success, -1 on error
> @@ -608,14 +608,14 @@ Returns: 0 on success, -1 on error
> Creates an interrupt controller model in the kernel. On x86, creates a virtual
> ioapic, a virtual PIC (two PICs, nested), and sets up future vcpus to have a
> local APIC. IRQ routing for GSIs 0-15 is set to both PIC and IOAPIC; GSI 16-23
> -only go to the IOAPIC. On ia64, a IOSAPIC is created.
> -
> +only go to the IOAPIC. On ia64, a IOSAPIC is created. On ARM, a GIC is
> +created.
>
> 4.25 KVM_IRQ_LINE
>
> Capability: KVM_CAP_IRQCHIP
> Architectures: x86, ia64, arm
> -Type: vm ioctl
> +Type: vm ioctl (and vcpu_ioctl on ARM)
so I'm worried about this mixed vcpu/kvm ioctl.
I think we're already signaling specific vcpus through the KVM
interface for non-gic stuff and I have a feeling that VCPU ioctls are
expected to be executed by a vcpu thread (??).
I don't know, either create a new ioctl, embed in the IRQ field or
change the struct (can we even do this?)
> Parameters: struct kvm_irq_level
> Returns: 0 on success, -1 on error
>
> @@ -624,9 +624,19 @@ On some architectures it is required that an interrupt controller model has
> been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered
> interrupts require the level to be set to 1 and then back to 0.
>
> -ARM uses two types of interrupt lines per CPU: IRQ and FIQ. The value of the
> -irq field should be (vcpu_index << 1) for IRQs and ((vcpu_index << 1) | 1) for
> -FIQs. Level is used to raise/lower the line.
> +ARM can signal an interrupt either at the CPU level, or at the
> +in-kernel irqchip (GIC), with the following convention:
> +
> +- CPU signaling: ARM uses two types of interrupt lines per CPU: IRQ
> + and FIQ. The value of the irq field should be (vcpu_index << 1) for
> + IRQs and ((vcpu_index << 1) | 1) for FIQs. As there's a limit of 8
> + CPUs, irq is between 0 and 15. This is a vm_ioctl.
> +
> +- GIC signaling: If signaling a PPI, this is a vcpu_ioctl, and irq is
> + between 16 and 31. If signaling a SPI, this is a vm_ioctl, and irq
> + is above 31.
> +
I suggest adding a comment that this is without loss of functionality,
as the irq's between 0 and 15 are used for SGIs for VGIC
implementations and these should never be injected from user space
anyhow.
> +In both cases, level is used to raise/lower the line.
>
> struct kvm_irq_level {
> union {
> --
> 1.7.7.1
>
Thanks,
-Christoffer
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2012-06-22 21:08 ` [Android-virt] [PATCH 10/15] ARM: KVM: VGIC: Update KVM API documentation Christoffer Dall
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