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Re: [Qemu-devel] [PATCH v3 4/4] ivshmem: Disable irqfd on device reset
From: |
Ladi Prosek |
Subject: |
Re: [Qemu-devel] [PATCH v3 4/4] ivshmem: Disable irqfd on device reset |
Date: |
Fri, 8 Dec 2017 14:44:03 +0100 |
On Fri, Dec 8, 2017 at 2:36 PM, Markus Armbruster <address@hidden> wrote:
> Ladi Prosek <address@hidden> writes:
>
>> The effects of ivshmem_enable_irqfd() was not undone on device reset.
>>
>> This manifested as:
>> ivshmem_add_kvm_msi_virq: Assertion `!s->msi_vectors[vector].pdev' failed.
>>
>> when irqfd was enabled before reset and then enabled again after reset,
>> making
>> ivshmem_enable_irqfd() run for the second time.
>>
>> To reproduce, run:
>>
>> ivshmem-server
>>
>> and QEMU with:
>>
>> -device ivshmem-doorbell,chardev=iv
>> -chardev socket,path=/tmp/ivshmem_socket,id=iv
>>
>> then install the Windows driver, at the time of writing available at:
>>
>> https://github.com/virtio-win/kvm-guest-drivers-windows/tree/master/ivshmem
>>
>> and crash-reboot the guest by inducing a BSOD.
>>
>> Signed-off-by: Ladi Prosek <address@hidden>
>> ---
>> hw/misc/ivshmem.c | 24 +++++++++++++-----------
>> 1 file changed, 13 insertions(+), 11 deletions(-)
>>
>> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
>> index d1bb246d12..4be0d2627b 100644
>> --- a/hw/misc/ivshmem.c
>> +++ b/hw/misc/ivshmem.c
>> @@ -758,17 +758,6 @@ static void ivshmem_msix_vector_use(IVShmemState *s)
>> }
>> }
>>
>> -static void ivshmem_reset(DeviceState *d)
>> -{
>> - IVShmemState *s = IVSHMEM_COMMON(d);
>> -
>> - s->intrstatus = 0;
>> - s->intrmask = 0;
>> - if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
>> - ivshmem_msix_vector_use(s);
>> - }
>> -}
>> -
>> static int ivshmem_setup_interrupts(IVShmemState *s, Error **errp)
>> {
>> /* allocate QEMU callback data for receiving interrupts */
>> @@ -855,6 +844,19 @@ static void ivshmem_disable_irqfd(IVShmemState *s)
>>
>> }
>>
>> +static void ivshmem_reset(DeviceState *d)
>> +{
>> + IVShmemState *s = IVSHMEM_COMMON(d);
>> +
>> + ivshmem_disable_irqfd(s);
>> +
>> + s->intrstatus = 0;
>> + s->intrmask = 0;
>> + if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
>> + ivshmem_msix_vector_use(s);
>> + }
>> +}
>> +
>> static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
>> uint32_t val, int len)
>> {
>
> Why are you moving ivshmem_reset()? Makes the actual change harder to
> see than necessary.
ivshmem_disable_irqfd() is declared after ivshmem_reset() in the
source file. I generally prefer to order static functions
topologically if possible. If you'd prefer adding a forward decl
instead (fewer lines touched, easier to bisect?) I can certainly do
that. Thanks!