On Wed, 4 Oct 2017 15:49:38 +0200
Pierre Morel <pmo...@linux.vnet.ibm.com> wrote:
"not supported", surely?
> In S390x the Adapter Interrupt Suppression facility is used to mask
> interrupts of other PCI devices during interruption handling.
>
> VFIO PCI allows the interrupts to be delivered rapidely through KVM via
> IRQfd or to be delivered through QEMU.
> The choice is made through the x-kvm-intx and x-kvo-misx properties of
> the VFIO PCI device.
>
> If the VFIO PCI device is using the direct KVM access through IRQfd and
> we know that KVM does not implement AIS support we refuse to realize the
> VFIO PCI device.
>
> In all other cases, emulation and VFIO PCI sending interrupts through
> QEMU, we intercept the propagated IRQ, and protect it with the QEMU AIS
> implementation before to send it to the guest through KVM.
>
> Signed-off-by: Pierre Morel <pmo...@linux.vnet.ibm.com>
> ---
> hw/s390x/s390-pci-bus.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
> index d9c294a..4afe49b 100644
> --- a/hw/s390x/s390-pci-bus.c
> +++ b/hw/s390x/s390-pci-bus.c
> @@ -21,18 +21,21 @@
> #include "hw/pci/pci_bus.h"
> #include "hw/pci/pci_bridge.h"
> #include "hw/pci/msi.h"
> +#include "hw/vfio/pci.h"
> #include "qemu/error-report.h"
>
> #ifndef DEBUG_S390PCI_BUS
> #define DEBUG_S390PCI_BUS 0
> #endif
>
> +#ifndef DPRINTF
> #define DPRINTF(fmt, ...) \
> do { \
> if (DEBUG_S390PCI_BUS) { \
> fprintf(stderr, "S390pci-bus: " fmt, ## __VA_ARGS__); \
> } \
> } while (0)
> +#endif
Ugh. Is there DPRINTF redefinition going on?
>
> S390pciState *s390_get_phb(void)
> {
> @@ -751,6 +754,15 @@ static void s390_pcihost_hot_plug(HotplugHandler
> *hotplug_dev,
> }
>
> if (object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
> + S390FLICState *fs = s390_get_flic();
> + VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> +
> + if ((!vdev->no_kvm_msix || !vdev->no_kvm_msix) &&
One of the no_kvm_msix should probably be something else :)
> + (!fs || !fs->ais_supported)) {
> + error_setg(errp, "VFIO PCI is not supported "
> + "because kernel has no AIS capability.");
I think failure is per-device (i.e., you would be able to plug a
different vfio device if you turned off irqfd support for it); should
that be reflected in the error message?
> + return;
> + }
Would it make sense to fail plugging before we try to create a zpci
device?
> pbdev->fh |= FH_SHM_VFIO;
> } else {
> pbdev->fh |= FH_SHM_EMUL;
