Hi Tom.
A few MSI issues below. Thanks,
Alex
On Tue, 2010-06-08 at 14:21 -0700, Tom Lyon wrote:
> diff -uprN linux-2.6.34/drivers/vfio/vfio_pci_config.c
> vfio-linux-2.6.34/drivers/vfio/vfio_pci_config.c
> --- linux-2.6.34/drivers/vfio/vfio_pci_config.c 1969-12-31
> 16:00:00.000000000 -0800
> +++ vfio-linux-2.6.34/drivers/vfio/vfio_pci_config.c 2010-05-28
> 14:26:47.000000000 -0700
> +/*
> + * Lengths of PCI Config Capabilities
> + * 0 means unknown (but at least 4)
> + * FF means special/variable
> + */
> +static u8 pci_capability_length[] = {
> + [PCI_CAP_ID_BASIC] = 64, /* pci config header */
> + [PCI_CAP_ID_PM] = PCI_PM_SIZEOF,
> + [PCI_CAP_ID_AGP] = PCI_AGP_SIZEOF,
> + [PCI_CAP_ID_VPD] = 8,
> + [PCI_CAP_ID_SLOTID] = 4,
> + [PCI_CAP_ID_MSI] = 0xFF, /* 10, 14, or 24 */
I think this is actually 10, 14, 20, or 24.
> +static struct perm_bits pci_cap_msi_perm[] = {
> + { 0, 0, }, /* 0x00 MSI message control */
> + { 0xFFFFFFFF, 0xFFFFFFFF, }, /* 0x04 MSI message address */
> + { 0xFFFFFFFF, 0xFFFFFFFF, }, /* 0x08 MSI message addr/data */
> + { 0x0000FFFF, 0x0000FFFF, }, /* 0x0c MSI message data */
> + { 0, 0xFFFFFFFF, }, /* 0x10 MSI mask bits */
> + { 0, 0xFFFFFFFF, }, /* 0x14 MSI pending bits */
> +};
Is there any reason for mask bits to have virtualized writes? I don't
think we can support all 4 MSI capability sizes with this one table. We
probably need a 32bit and 64bit version, then we can drop the mask,
pending, and reserved fields via the length.
> + if (len == 0xFF) {
> + switch (cap) {
> + case PCI_CAP_ID_MSI:
> + ret = pci_read_config_word(pdev,
> + pos + PCI_MSI_FLAGS, &flags);
> + if (ret < 0)
> + return ret;
> + if (flags & PCI_MSI_FLAGS_MASKBIT)
> + /* per vec masking */
> + len = 24;
> + else if (flags & PCI_MSI_FLAGS_64BIT)
These aren't mutually exclusive features aiui.
> + /* 64 bit */
> + len = 14;
> + else
> + len = 10;
> + break;
This should probably be something like
len = 10;
if (flags & PCI_MSI_FLAGS_MASKBIT)
len += 10;
if (flags & PCI_MSI_FLAGS_64BIT) {
/* set 64bit permission table */
len += 4;
} else
/* set 32bit permission table */
> diff -uprN linux-2.6.34/include/linux/vfio.h
> vfio-linux-2.6.34/include/linux/vfio.h
> --- linux-2.6.34/include/linux/vfio.h 1969-12-31 16:00:00.000000000 -0800
> +++ vfio-linux-2.6.34/include/linux/vfio.h 2010-06-07 12:20:06.000000000
> -0700
> +/* request MSI interrupts; use given eventfd */
> +#define VFIO_EVENTFD_MSI _IOW(';', 105, int)
Any intention of supporting MSI multiple message capability? If so,
this might turn into the same interface as MSIX.
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