On Tue, Dec 29, 2015 at 04:46:03PM +0800, Cao jin wrote:
> Signed-off-by: Cao jin <caoj.f...@cn.fujitsu.com>
> ---
> changelog v4:
> 1. strip the bugfix code, but I guess this patch should be applied after
> that bugfix patch.
> 2. Other little fix as per previous review
>
> Some explanation to previous review:
> 1. error_setg_errno() I use in this patch will print the strerror(errno), so I
> guess it will be informative enough? example:
>
> error_setg_errno(errp, errno, "open %s fail", path); will print:
> "open bluhbluh fail: string_from_strerrer(errno)"
I'd prefer some mention of why this is attempted too.
E.g. "igd passthrough : open bluhbluh fail"
> 2. snprintf() has tiny tiny chance to fail,
It just formats a string into a buffer. the buffer
is pre-allocated, and we know it's large enough for the data.
How can it fail?
> I don`t assert here, because this
> device is on-board, it init during machine initialization, in case it
> fails,
> the errp we set will results in error_report(err) and exit(1), at least can
> let user know why fail. see the call-chain:
>
> pc_xen_hvm_init_pci->pc_init1->i440fx_init->pci_create_simple->
> pci_create_simple_multifunction->qdev_init_nofail
unlike open failing, there's nothing user can do, this means there's
a coding bug somewhere, and assert is easier to debug.
> About test:
> 1. Compiled
> 2. Did a dirty hack to force create/realize this device in pc_init1(), prove
> that the realizing process is ok, I will reply this mail later to attch the
> screenshot evidence
Good job, thanks!
You should also Cc Tiejun Chen <tiejun.c...@intel.com> who wrote this
code, presumably with access to hardware to test on.
> hw/pci-host/piix.c | 30 +++++++++++++++---------------
> 1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
> index a9cb983..e91570f 100644
> --- a/hw/pci-host/piix.c
> +++ b/hw/pci-host/piix.c
> @@ -761,7 +761,7 @@ static const IGDHostInfo igd_host_bridge_infos[] = {
> {0xa8, 4}, /* SNB: base of GTT stolen memory */
> };
>
> -static int host_pci_config_read(int pos, int len, uint32_t *val)
> +static void host_pci_config_read(int pos, int len, uint32_t *val, Error
> **errp)
> {
> char path[PATH_MAX];
> int config_fd;
> @@ -769,19 +769,19 @@ static int host_pci_config_read(int pos, int len,
> uint32_t *val)
> /* Access real host bridge. */
> int rc = snprintf(path, size,
> "/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
> 0, 0, 0, 0, "config");
> - int ret = 0;
>
> if (rc >= size || rc < 0) {
> - return -ENODEV;
> + error_setg_errno(errp, errno, "snprintf err");
> }
>
> config_fd = open(path, O_RDWR);
> if (config_fd < 0) {
> - return -ENODEV;
> + error_setg_errno(errp, errno, "open %s fail", path);
> + return;
> }
>
> if (lseek(config_fd, pos, SEEK_SET) != pos) {
> - ret = -errno;
> + error_setg_errno(errp, errno, "lseek err");
> goto out;
> }
>
> @@ -789,32 +789,32 @@ static int host_pci_config_read(int pos, int len,
> uint32_t *val)
> rc = read(config_fd, (uint8_t *)val, len);
> } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
> if (rc != len) {
> - ret = -errno;
> + error_setg_errno(errp, errno, "read err");
> }
>
> out:
> close(config_fd);
> - return ret;
> }
>
> -static int igd_pt_i440fx_initfn(struct PCIDevice *pci_dev)
> +static void igd_pt_i440fx_realize(struct PCIDevice *pci_dev, Error **errp)
> {
> uint32_t val = 0;
> - int rc, i, num;
> + int i, num;
> int pos, len;
> + Error *local_err = NULL;
>
> num = ARRAY_SIZE(igd_host_bridge_infos);
> for (i = 0; i < num; i++) {
> pos = igd_host_bridge_infos[i].offset;
> len = igd_host_bridge_infos[i].len;
> - rc = host_pci_config_read(pos, len, &val);
> - if (rc) {
> - return -ENODEV;
> +
> + host_pci_config_read(pos, len, &val, &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + return;
> }
> pci_default_write_config(pci_dev, pos, cpu_to_le32(val), len);
> }
> -
> - return 0;
> }
>
> static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void *data)
> @@ -822,7 +822,7 @@ static void igd_passthrough_i440fx_class_init(ObjectClass
> *klass, void *data)
> DeviceClass *dc = DEVICE_CLASS(klass);
> PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
>
> - k->init = igd_pt_i440fx_initfn;
> + k->realize = igd_pt_i440fx_realize;
> dc->desc = "IGD Passthrough Host bridge";
> }
>
> --
> 2.1.0
>
>
