[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v3 07/11] igd: revamp host config read
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH v3 07/11] igd: revamp host config read |
Date: |
Wed, 6 Jan 2016 15:02:44 +0000 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Tue, 5 Jan 2016, Gerd Hoffmann wrote:
> Move all work to the host_pci_config_copy helper function,
> which we can easily reuse when adding q35 support.
> Open sysfs file only once for all values. Use pread.
> Proper error handling. Fix bugs:
>
> * Don't throw away results (like old host_pci_config_read
> did because val was passed by value not reference).
> * Update config space directly (writing via
> pci_default_write_config only works for registers
> whitelisted in wmask).
>
> Hmm, this code can hardly ever worked before,
> /me wonders what test coverage it had.
>
> With this patch in place igd-passthru=on actually
> works, although it still requires root priviledges
> because linux refuses to allow non-root users access
> pci config space above offset 0x50.
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
> hw/pci-host/igd.c | 65
> +++++++++++++++++++++++--------------------------------
> 1 file changed, 27 insertions(+), 38 deletions(-)
>
> diff --git a/hw/pci-host/igd.c b/hw/pci-host/igd.c
> index 0784128..ec48875 100644
> --- a/hw/pci-host/igd.c
> +++ b/hw/pci-host/igd.c
> @@ -19,47 +19,39 @@ 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_copy(PCIDevice *guest, const char *host,
> + const IGDHostInfo *list, int len, Error
> **errp)
> {
> - char path[PATH_MAX];
> - int config_fd;
> - ssize_t size = sizeof(path);
> - /* 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;
> + char *path;
> + int config_fd, rc, i;
>
> - if (rc >= size || rc < 0) {
> - return -ENODEV;
> - }
> -
> - config_fd = open(path, O_RDWR);
> + path = g_strdup_printf("/sys/bus/pci/devices/%s/config", host);
> + config_fd = open(path, O_RDONLY);
> if (config_fd < 0) {
> - return -ENODEV;
> + error_setg_file_open(errp, errno, path);
> + goto out_free;
> }
>
> - if (lseek(config_fd, pos, SEEK_SET) != pos) {
> - ret = -errno;
> - goto out;
> + for (i = 0; i < len; i++) {
> + rc = pread(config_fd, guest->config + list[i].offset,
> + list[i].len, list[i].offset);
> + if (rc != list[i].len) {
pread is allowed to return early, returning the number of bytes read.
> + error_setg_errno(errp, errno, "read %s, offset 0x%x",
> + path, list[i].offset);
> + goto out_close;
> + }
> }
> - do {
> - rc = read(config_fd, (uint8_t *)&val, len);
> - } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
> - if (rc != len) {
> - ret = -errno;
> - }
> -out:
> +
> +out_close:
> close(config_fd);
> - return ret;
> +out_free:
> + g_free(path);
> }
>
> static void (*i440fx_realize)(PCIDevice *pci_dev, Error **errp);
> static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
> {
> Error *err = NULL;
> - uint32_t val = 0;
> - int rc, i, num;
> - int pos, len;
>
> i440fx_realize(pci_dev, &err);
> if (err != NULL) {
> @@ -67,16 +59,13 @@ static void igd_pt_i440fx_realize(PCIDevice *pci_dev,
> Error **errp)
> return;
> }
>
> - 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) {
> - error_setg(errp, "failed to read host config");
> - return;
> - }
> - pci_default_write_config(pci_dev, pos, val, len);
> + host_pci_config_copy(pci_dev, "0000:00:00.0",
> + igd_host_bridge_infos,
> + ARRAY_SIZE(igd_host_bridge_infos),
> + &err);
> + if (err != NULL) {
> + error_propagate(errp, err);
> + return;
> }
> }
>
> --
> 1.8.3.1
>
- Re: [Qemu-devel] [PATCH v3 04/11] igd: switch TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE to realize, (continued)
[Qemu-devel] [PATCH v3 08/11] igd: add q35 support, Gerd Hoffmann, 2016/01/05
[Qemu-devel] [PATCH v3 03/11] pc: move igd support code to igd.c, Gerd Hoffmann, 2016/01/05
[Qemu-devel] [PATCH v3 07/11] igd: revamp host config read, Gerd Hoffmann, 2016/01/05
- Re: [Qemu-devel] [PATCH v3 07/11] igd: revamp host config read,
Stefano Stabellini <=
[Qemu-devel] [PATCH v3 10/11] igd: handle igd-passthrough-isa-bridge setup in realize(), Gerd Hoffmann, 2016/01/05
[Qemu-devel] [PATCH v3 09/11] igd: move igd-passthrough-isa-bridge to igd.c too, Gerd Hoffmann, 2016/01/05
[Qemu-devel] [PATCH v3 11/11] igd: move igd-passthrough-isa-bridge creation to machine init, Gerd Hoffmann, 2016/01/05