I have tried to use msi only, but failed again. Is there and documentation
details this?
From: Qemu-devel on behalf
of Douglas Su
Sent: Thursday, October 22, 2020 20:32
To: QEMU Developers
Subject: Enable MSI-X support in PCIe device.
To use MSI-X interrupt in my PCIe device, In realize() function I make a MSIX
initialization like this:
#define MYDEV_MSIX_VEC_NUM 5
void realize() {
memory_region_init(>msix, OBJECT(edu), "mydev-msix",
MYDEV_MSIX_SIZE);
pci_register_bar(pdev, MYDEV_MSIX_IDX,
PCI_BASE_ADDRESS_SPACE_MEMORY, >msix);
rv = msix_init(pdev, MYDEV_MSIX_VEC_NUM,
>msix, MYDEV_MSIX_IDX, MYDEV_MSIX_TABLE,
>msix, MYDEV_MSIX_IDX, MYDEV_MSIX_PBA,
0, errp);
}
After this, a simple logic is added to trigger interrupt by writing command to
a specific BAR0 address.
void trigger() {
msix_notify(pdev, 1); // send vector 1 to msix
}
In the OS driver, MSIX is enabled via `pci_alloc_irq_vectors()`, which is
detailed in Linux Kernel's documentation `Documentation/PCI/msi-howto.rst` (I
use kernel 5.7).
It is correct to obtain the number of vector from that function but failed to
receive interrupt from device. The IRQ, which is returned from
`pci_irq_vector`, is registered via `request_irq()` in the deriver.
Can anyone give a clue?
