On Sun, Dec 04, 2011 at 04:47:17PM -0700, Cam Macdonell wrote: > On Sun, Dec 4, 2011 at 3:20 AM, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Fri, Dec 02, 2011 at 04:34:21PM -0700, Cam Macdonell wrote: > >> Based on a git bisect, this patch breaks msi-x interrupt delivery in > >> the ivshmem device. > > > > I think the following should fix it. Compiled-only - > > could you pls check? If yes let's apply to the stable branch. > > Thanks for the patch Michael. > > It addresses the need for msix_write_config() to be called, but the > addition of the msix_reset() is causing a reset of the vectors after > they've been initialized in pci_ivshmem_init(). So, interrupts still > aren't delivered with this patch applied as it is. > > In particular, a reset occurs after pci_ivshmem_init runs, so the > msix_entry_used array is reset to 0s, which causes the interrupt > delivery to fail. > > If I comment out the msix_reset(), then interrupts are delivered. > Would the reset be caused by a bug in the guest driver? or do I need > to reconfigure the msix after reset? I'm unclear as to the proper > behaviour after a reset. > > Thanks, > Cam >
I didn't anticipate this, virtio only configures vectors when msi-x is enabled. For 1.0 it's safest to do the same and just re-enable after reset. So we'll end up with something like the following - does it help? Side note: exit(1) is not the best way to handle errors in the init function. I think you should add error_report, then goto err on failures to init, cleanup what you have set up meanwhile and return an error code. diff --git a/hw/ivshmem.c b/hw/ivshmem.c index 242fbea..c58f4d3 100644 --- a/hw/ivshmem.c +++ b/hw/ivshmem.c @@ -500,11 +500,29 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags) return; } +/* Select the MSI-X vectors used by device. + * ivshmem maps events to vectors statically, so + * we just enable all vectors on init and after reset. */ +static void ivshmem_use_msix(IVShmemState * s) +{ + int i; + + if (!msix_present(&s->dev)) { + return; + } + + for (i = 0; i < s->vectors; i++) { + msix_vector_use(&s->dev, i); + } +} + static void ivshmem_reset(DeviceState *d) { IVShmemState *s = DO_UPCAST(IVShmemState, dev.qdev, d); s->intrstatus = 0; + msix_reset(&s->dev); + ivshmem_use_msix(s); return; } @@ -535,12 +553,8 @@ static uint64_t ivshmem_get_size(IVShmemState * s) { return value; } -static void ivshmem_setup_msi(IVShmemState * s) { - - int i; - - /* allocate the MSI-X vectors */ - +static void ivshmem_setup_msi(IVShmemState * s) +{ memory_region_init(&s->msix_bar, "ivshmem-msix", 4096); if (!msix_init(&s->dev, s->vectors, &s->msix_bar, 1, 0)) { pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, @@ -551,13 +565,10 @@ static void ivshmem_setup_msi(IVShmemState * s) { exit(1); } - /* 'activate' the vectors */ - for (i = 0; i < s->vectors; i++) { - msix_vector_use(&s->dev, i); - } - /* allocate Qemu char devices for receiving interrupts */ s->eventfd_table = g_malloc0(s->vectors * sizeof(EventfdEntry)); + + ivshmem_use_msix(s); } static void ivshmem_save(QEMUFile* f, void *opaque) @@ -610,6 +621,13 @@ static int ivshmem_load(QEMUFile* f, void *opaque, int version_id) return 0; } +static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address, + uint32_t val, int len) +{ + pci_default_write_config(pci_dev, address, val, len); + msix_write_config(pci_dev, address, val, len); +} + static int pci_ivshmem_init(PCIDevice *dev) { IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev); @@ -734,6 +752,8 @@ static int pci_ivshmem_init(PCIDevice *dev) } + s->dev.config_write = ivshmem_write_config; + return 0; }