On Tue, Sep 28, 2010 at 05:44:10PM +0800, Sheng Yang wrote:
> This patch enable per-vector mask for assigned devices using MSI-X.
>
> Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
I think I see an issue here, noted below. Some general comments:
- The mask bit seems broken for injecting interrupts from
userspace (with interrupts/ioctls).
I think we must test it on injection path.
- We'll need a way to support the pending bit.
Disabling interrupts will not let us do it.
> ---
> arch/x86/kvm/x86.c | 1 +
> include/linux/kvm.h | 9 ++++++++-
> include/linux/kvm_host.h | 1 +
> virt/kvm/assigned-dev.c | 39 +++++++++++++++++++++++++++++++++++++++
> 4 files changed, 49 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 8412c91..e6933e6 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1927,6 +1927,7 @@ int kvm_dev_ioctl_check_extension(long ext)
> case KVM_CAP_DEBUGREGS:
> case KVM_CAP_X86_ROBUST_SINGLESTEP:
> case KVM_CAP_XSAVE:
> + case KVM_CAP_DEVICE_MSIX_MASK:
> r = 1;
> break;
> case KVM_CAP_COALESCED_MMIO:
> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
> index 919ae53..f2b7cdc 100644
> --- a/include/linux/kvm.h
> +++ b/include/linux/kvm.h
> @@ -540,6 +540,9 @@ struct kvm_ppc_pvinfo {
> #endif
> #define KVM_CAP_PPC_GET_PVINFO 57
> #define KVM_CAP_PPC_IRQ_LEVEL 58
> +#ifdef __KVM_HAVE_MSIX
> +#define KVM_CAP_DEVICE_MSIX_MASK 59
> +#endif
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
> @@ -787,11 +790,15 @@ struct kvm_assigned_msix_nr {
> };
>
> #define KVM_MAX_MSIX_PER_DEV 256
> +
> +#define KVM_MSIX_FLAG_MASK 1
> +
> struct kvm_assigned_msix_entry {
> __u32 assigned_dev_id;
> __u32 gsi;
> __u16 entry; /* The index of entry in the MSI-X table */
> - __u16 padding[3];
> + __u16 flags;
> + __u16 padding[2];
> };
>
> #endif /* __LINUX_KVM_H */
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 0b89d00..a43405c 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -415,6 +415,7 @@ struct kvm_irq_ack_notifier {
> };
>
> #define KVM_ASSIGNED_MSIX_PENDING 0x1
> +#define KVM_ASSIGNED_MSIX_MASK 0x2
> struct kvm_guest_msix_entry {
> u32 vector;
> u16 entry;
> diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
> index 7c98928..15b8c32 100644
> --- a/virt/kvm/assigned-dev.c
> +++ b/virt/kvm/assigned-dev.c
> @@ -17,6 +17,8 @@
> #include <linux/pci.h>
> #include <linux/interrupt.h>
> #include <linux/slab.h>
> +#include <linux/irqnr.h>
> +
> #include "irq.h"
>
> static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
> @@ -666,6 +668,30 @@ msix_nr_out:
> return r;
> }
>
> +static void update_msix_mask(struct kvm_assigned_dev_kernel *assigned_dev,
> + int index)
> +{
> + int irq;
> +
> + if (!assigned_dev->dev->msix_enabled ||
> + !(assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX))
> + return;
> +
> + irq = assigned_dev->host_msix_entries[index].vector;
> +
> + ASSERT(irq != 0);
> +
> + if (assigned_dev->guest_msix_entries[index].flags &
> + KVM_ASSIGNED_MSIX_MASK)
> + disable_irq(irq);
> + else {
> + enable_irq(irq);
> + if (assigned_dev->guest_msix_entries[index].flags &
> + KVM_ASSIGNED_MSIX_PENDING)
> + schedule_work(&assigned_dev->interrupt_work);
> + }
> +}
> +
What happens if guest masks an entry and then we hot-unplug the
device and remove it from guest? It looks like interrupt
will stay disabled?
> static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
> struct kvm_assigned_msix_entry *entry)
> {
> @@ -688,6 +714,19 @@ static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
> adev->guest_msix_entries[i].entry = entry->entry;
> adev->guest_msix_entries[i].vector = entry->gsi;
> adev->host_msix_entries[i].entry = entry->entry;
> + if ((entry->flags & KVM_MSIX_FLAG_MASK) &&
> + !(adev->guest_msix_entries[i].flags &
> + KVM_ASSIGNED_MSIX_MASK)) {
> + adev->guest_msix_entries[i].flags |=
> + KVM_ASSIGNED_MSIX_MASK;
> + update_msix_mask(adev, i);
> + } else if (!(entry->flags & KVM_MSIX_FLAG_MASK) &&
> + (adev->guest_msix_entries[i].flags &
> + KVM_ASSIGNED_MSIX_MASK)) {
> + adev->guest_msix_entries[i].flags &=
> + ~KVM_ASSIGNED_MSIX_MASK;
> + update_msix_mask(adev, i);
> + }
> break;
> }
> if (i == adev->entries_nr) {
> --
> 1.7.0.1
>
> --
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