[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 18/38] ivshmem: Leave INTx alone when using MSI-
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 18/38] ivshmem: Leave INTx alone when using MSI-X |
Date: |
Wed, 2 Mar 2016 15:15:48 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 02/03/2016 12:04, Markus Armbruster wrote:
> For better or worse, fallback to INTx has never been implemented in
> ivshmem. You can either ask for an INTx-only device (msi=off), or for
> an MSI-X-only device (msi=on). The latter *cannot* do interrupts until
> you enable MSI-X.
Aha, now I see what you mean:
if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
msix_notify(pdev, vector);
} else {
ivshmem_IntrStatus_write(s, 1);
}
So I believe your patch is okay. Perhaps you could also change the
interrupt pin for new machine types (even without changing the
revision), but it's not necessary to do it.
> Similarly, the ivshmem-doorbell device introduced later in this series
> can only do MSI-X, and the ivshmem-plain device cannot do interrupts at
> all.
Here:
dev->config[PCI_INTERRUPT_PIN] = 0x01; /* interrupt pin 1 */
Paolo