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Re: [Qemu-devel] [PATCH for v1.0 1/3] msix: track function masked in pci
Re: [Qemu-devel] [PATCH for v1.0 1/3] msix: track function masked in pci device state
Sun, 4 Dec 2011 16:47:17 -0700
On Sun, Dec 4, 2011 at 3:20 AM, Michael S. Tsirkin <address@hidden> 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.
> ivshmem: add missing msix calls
> ivshmem used msix but didn't call it on either reset or
> config write paths. This used to partically work since
> guests don't use all of msi-x configuration fields,
> and reset is rarely used, but the patch 'msix: track function masked
> in pci device state' broke that. Fix by adding appropriate calls.
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index 242fbea..3680c0f 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -505,6 +505,7 @@ static void ivshmem_reset(DeviceState *d)
> IVShmemState *s = DO_UPCAST(IVShmemState, dev.qdev, d);
> s->intrstatus = 0;
> + msix_reset(&s->dev);
> @@ -610,6 +611,13 @@ static int ivshmem_load(QEMUFile* f, void *opaque, int
> 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 +742,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
> + s->dev.config_write = ivshmem_write_config;
> return 0;