On 10/04/2013 01:39 AM, Alex Williamson wrote:
> During vfio-pci initfn, the device is not always in a state where the
> option ROM can be read. In the case of graphics cards, there's often
> no per function reset, which means we have host driver state affecting
> whether the option ROM is usable. Ideally we want to move reading the
> option ROM past any co-assigned device resets to the point where the
> guest first tries to read the ROM itself.
>
> To accomplish this, we switch the memory region for the option rom to
> an I/O region rather than a memory mapped region. This has the side
> benefit that we don't waste KVM memory slots for a BAR where we don't
> care about performance. This also allows us to delay loading the ROM
> from the device until the first read by the guest. We then use the
> PCI config space size of the ROM BAR when setting up the BAR through
> QEMU PCI.
>
> Another benefit of this approach is that previously when a user set
> the ROM to a file using the romfile= option, we still probed VFIO for
> the parameters of the ROM, which can result in dmesg errors about an
> invalid ROM. We now only probe VFIO to get the ROM contents if the
> guest actually tries to read the ROM.
>
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
> hw/misc/vfio.c | 184 +++++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 122 insertions(+), 62 deletions(-)
>
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index ede026d..730dec5 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -166,6 +166,7 @@ typedef struct VFIODevice {
> off_t config_offset; /* Offset of config space region within device fd */
> unsigned int rom_size;
> off_t rom_offset; /* Offset of ROM region within device fd */
> + void *rom;
> int msi_cap_size;
> VFIOMSIVector *msi_vectors;
> VFIOMSIXInfo *msix;
> @@ -1058,6 +1059,125 @@ static const MemoryRegionOps vfio_bar_ops = {
> .endianness = DEVICE_LITTLE_ENDIAN,
> };
>
> +static void vfio_pci_load_rom(VFIODevice *vdev)
> +{
> + struct vfio_region_info reg_info = {
> + .argsz = sizeof(reg_info),
> + .index = VFIO_PCI_ROM_REGION_INDEX
> + };
> + uint64_t size;
> + off_t off = 0;
> + size_t bytes;
> +
> + if (ioctl(vdev->fd, VFIO_DEVICE_GET_REGION_INFO, ®_info)) {
> + error_report("vfio: Error getting ROM info: %m");
> + return;
> + }
> +
> + DPRINTF("Device %04x:%02x:%02x.%x ROM:\n", vdev->host.domain,
> + vdev->host.bus, vdev->host.slot, vdev->host.function);
> + DPRINTF(" size: 0x%lx, offset: 0x%lx, flags: 0x%lx\n",
> + (unsigned long)reg_info.size, (unsigned long)reg_info.offset,
> + (unsigned long)reg_info.flags);
> +
> + vdev->rom_size = size = reg_info.size;
> + vdev->rom_offset = reg_info.offset;
> +
> + if (!vdev->rom_size) {
> + return;
> + }
> +
> + vdev->rom = g_malloc(size);
> + memset(vdev->rom, 0xff, size);
> +
> + while (size) {
> + bytes = pread(vdev->fd, vdev->rom + off, size, vdev->rom_offset + off);
> + if (bytes == 0) {
> + break;
> + } else if (bytes > 0) {
> + off += bytes;
> + size -= bytes;
> + } else {
> + if (errno == EINTR || errno == EAGAIN) {
> + continue;
> + }
> + error_report("vfio: Error reading device ROM: %m");
> + break;
> + }
> + }
> +}
> +
> +static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size)
> +{
> + VFIODevice *vdev = opaque;
> + uint64_t val = ((uint64_t)1 << (size * 8)) - 1;
> +
> + /* Load the ROM lazily when the guest tries to read it */
> + if (unlikely(!vdev->rom)) {
> + vfio_pci_load_rom(vdev);
> + }
> +
> + memcpy(&val, vdev->rom + addr,
> + (addr < vdev->rom_size) ? MIN(size, vdev->rom_size - addr) : 0);
> +
> + DPRINTF("%s(%04x:%02x:%02x.%x, 0x%"HWADDR_PRIx", 0x%x) = 0x%"PRIx64"\n",
> + __func__, vdev->host.domain, vdev->host.bus, vdev->host.slot,
> + vdev->host.function, addr, size, val);
> +
> + return val;
> +}
> +
> +static const MemoryRegionOps vfio_rom_ops = {
> + .read = vfio_rom_read,
> + .endianness = DEVICE_LITTLE_ENDIAN,
> +};
> +
> +static void vfio_pci_size_rom(VFIODevice *vdev)
> +{
> + uint32_t orig, size = (uint32_t)PCI_ROM_ADDRESS_MASK;
> + off_t offset = vdev->config_offset + PCI_ROM_ADDRESS;
> + char name[32];
> +
> + if (vdev->pdev.romfile || !vdev->pdev.rom_bar) {
> + return;
> + }
> +
> + /*
> + * Use the same size ROM BAR as the physical device. The contents
> + * will get filled in later when the guest tries to read it.
> + */
> + if (pread(vdev->fd, &orig, 4, offset) != 4 ||
> + pwrite(vdev->fd, &size, 4, offset) != 4 ||
> + pread(vdev->fd, &size, 4, offset) != 4 ||
> + pwrite(vdev->fd, &orig, 4, offset) != 4) {
Do not you want to do byteswapping here?
This chunk fails on powerpc64. The rest works (with the corresponding
kernel changes).
--
Alexey
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