Re: [PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-28 Thread Cédric Le Goater
On 4/28/22 09:26, Alexey Kardashevskiy wrote: On 4/28/22 16:25, Cédric Le Goater wrote: On 4/28/22 07:32, Alexey Kardashevskiy wrote: On 4/27/22 17:36, Cédric Le Goater wrote: Hello Alexey, On 4/27/22 06:36, Alexey Kardashevskiy wrote: VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimizati

Re: [PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-28 Thread Alexey Kardashevskiy
On 4/28/22 16:25, Cédric Le Goater wrote: On 4/28/22 07:32, Alexey Kardashevskiy wrote: On 4/27/22 17:36, Cédric Le Goater wrote: Hello Alexey, On 4/27/22 06:36, Alexey Kardashevskiy wrote: VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimization for INTx EOI handling when KVM can unmask P

Re: [PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-27 Thread Cédric Le Goater
On 4/28/22 07:32, Alexey Kardashevskiy wrote: On 4/27/22 17:36, Cédric Le Goater wrote: Hello Alexey, On 4/27/22 06:36, Alexey Kardashevskiy wrote: VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimization for INTx EOI handling when KVM can unmask PCI INTx (level triggered interrupt) without sw

Re: [PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-27 Thread Alexey Kardashevskiy
On 4/27/22 17:36, Cédric Le Goater wrote: Hello Alexey, On 4/27/22 06:36, Alexey Kardashevskiy wrote: VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimization for INTx EOI handling when KVM can unmask PCI INTx (level triggered interrupt) without switching to the userspace (==QEMU). Unfortunat

Re: [PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-27 Thread Cédric Le Goater
Hello Alexey, On 4/27/22 06:36, Alexey Kardashevskiy wrote: VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimization for INTx EOI handling when KVM can unmask PCI INTx (level triggered interrupt) without switching to the userspace (==QEMU). Unfortunately XIVE does not support level interrupts,

[PATCH qemu] spapr_pci: Disable IRQFD resampling on XIVE

2022-04-26 Thread Alexey Kardashevskiy
VFIO-PCI has an "KVM_IRQFD_FLAG_RESAMPLE" optimization for INTx EOI handling when KVM can unmask PCI INTx (level triggered interrupt) without switching to the userspace (==QEMU). Unfortunately XIVE does not support level interrupts, QEMU emulates them and therefore there is no existing code path t