Hi Cédric, Thanks for this information. I'll send v2 later. Jing
> On 9/15/2023 3:42 PM, Cédric Le Goater <c...@redhat.com> wrote: > > On 9/15/23 09:40, Liu, Jing2 wrote: > > Friendly ping to have your valuable inputs and comments. > > Thanks very much. > > I think that was done. We are waiting for the v2. > > Thanks, > > C. > > > > > > BRs, > > Jing > > > >> On 8/22/2023 3:29 PM, Jing Liu wrote: > >> Changes since RFC v1: > >> - RFC v1: https://www.mail-archive.com/qemu- > >> de...@nongnu.org/msg978637.html > >> - Revise the comments. (Alex) > >> - Report error of getting irq info and remove the trace of failure > >> case. (Alex, Cédric) > >> - Only store dynamic allocation flag as a bool type and test > >> accordingly. (Alex) > >> - Move dynamic allocation detection to vfio_msix_early_setup(). > >> (Alex) > >> - Change the condition logic in vfio_msix_vector_do_use() that moving > >> the defer_kvm_irq_routing test out and create a common place to update > >> nr_vectors. (Alex) > >> - Consolidate the way of MSI-X enabling during device initialization and > >> interrupt restoring that uses fd = -1 trick. Create a function doing > >> that. (Alex) > >> > >> Before kernel v6.5, dynamic allocation of MSI-X interrupts was not > >> supported. > >> Qemu therefore when allocating a new interrupt, should first release > >> all previously allocated interrupts (including disable of MSI-X) and > >> re-allocate all interrupts that includes the new one. > >> > >> The kernel series [1] adds the support of dynamic MSI-X allocation to > >> vfio-pci and uses the existing flag VFIO_IRQ_INFO_NORESIZE to guide > >> user space, that when dynamic MSI-X is supported the flag is cleared. > >> > >> This series makes the behavior for VFIO PCI devices when dynamic > >> MSI-X allocation is supported. When guest unmasks an interrupt, Qemu > >> can directly allocate an interrupt on host for this and has nothing > >> to do with the previously allocated ones. Therefore, host only > >> allocates interrupts for those unmasked > >> (enabled) interrupts inside guest when dynamic MSI-X allocation is > >> supported by device. > >> > >> When guests enable MSI-X with all of the vectors masked, Qemu need > >> match the state to enable MSI-X with no vector enabled. During > >> migration restore, Qemu also need enable MSI-X first in dynamic > >> allocation mode, to avoid the guest unused vectors being allocated on > >> host. To consolidate them, we use vector 0 with an invalid fd to get MSI-X > enabled and create a common function for this. > >> This is cleaner than setting userspace triggering and immediately release. > >> > >> Any feedback is appreciated. > >> > >> Jing > >> > >> [1] https://lwn.net/Articles/931679/ > >> > >> Jing Liu (4): > >> vfio/pci: detect the support of dynamic MSI-X allocation > >> vfio/pci: enable vector on dynamic MSI-X allocation > >> vfio/pci: use an invalid fd to enable MSI-X > >> vfio/pci: enable MSI-X in interrupt restoring on dynamic > >> allocation > >> > >> hw/vfio/pci.c | 126 +++++++++++++++++++++++++++++++++---------- > >> hw/vfio/pci.h | 1 + > >> hw/vfio/trace-events | 2 +- > >> 3 files changed, 101 insertions(+), 28 deletions(-) > >> > >> -- > >> 2.27.0 > >
